Astronomija

Asteroseizmologija; posnetki trajanja zvezdnih vibracij in razpoložljivosti podatkov?

Asteroseizmologija; posnetki trajanja zvezdnih vibracij in razpoložljivosti podatkov?


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Kratek video z naslovom "Zakaj Tess snema" zvoke zvezd "na dnu strani članka BBC News Planet-hunter lansira s Floride daje kratek opis asteroseizmologije astronoma Billa Chaplina z Univerze v Birminghamu.

Menda so tukaj predvajani zvoki nekakšne fotometrične meritve zvezd, ki so bile predvajane nekaj zaporedjev hitreje, da so bile slišne.

Rad bi jih poslušal več ali celo prenesel datoteko .wav ali podobno in si spet ogledal spekter iz zabave.

Z iskanjem mi je uspelo najti to spletno stran Univerze v Birminghamu in predvaja zvočne posnetke štirih zvezdic, ko je kurzor postavljen nad vsako od njih (predpostavljam, da zaradi nalaganja traja nekaj časa, da postane odziven).

http://bison.ph.bham.ac.uk/~miglioa/M4PR/M4_beta0.html

  1. Približno koliko časa je potreben čas opazovanja zvezde, da so ti avdio posnetki dolgi nekaj sekund?

  2. Kje lahko najdem prenosljive podatke; bodisi te zvočne posnetke .wav bodisi bolj tradicionalne datoteke s surovimi podatki, ki bi jih lahko analiziral?


Razkrito: "neverjetno" preživetje eksoplaneta

Skupina, v kateri je bil astronom z Univerze v Warwicku, je z uporabo asteroseizmologije pregledala parametre dveh zvezd rdečih velikanov, za katere je znano, da gostijo eksoplanete, in ena izmed njih je na podlagi trenutnih teorij ugotovila, da planet ne bi smel obstajati na sedanji lokaciji.

Uporaba asteroseizmičnega 1 podatki NASA-jeve mednarodne ekipe Transiting Exoplanet Survey Satellite (TESS) 2 vključno z raziskovalcem Univerze v Warwicku in pod vodstvom Inštituta za astrofiziko e Ciências do Espaço 3 preučeval zvezde rdečih velikan HD 212771 in HD 203949. To so prva zaznavanja nihanj v prej znanih zvezdah gostiteljicah eksoplanetov s strani TESS. Rezultat je bil danes objavljen v članku 4 v Astrofizični časopis.

Vodilni avtor Tiago Campante (IA & amp; Faculdade de Ciências da Universidade do Porto - FCUP) pojasnjuje, da je bilo odkrivanje teh nihanj mogoče le zato, ker: „Opazovanja TESS so dovolj natančna, da omogočajo merjenje nežnih pulzacij na površinah zvezd. Ti dve dokaj razviti zvezdi gostita tudi planeta, ki sta idealno preizkuševalno mesto za preučevanje razvoja planetarnih sistemov. "

Po določitvi fizikalnih lastnosti obeh zvezd, kot so njihova masa, velikost in starost, so z asteroseizmologijo osredotočili svojo pozornost na evolucijsko stanje HD 203949. Njihov cilj je bil razumeti, kako bi se njen planet lahko izognil zajetju, saj ovoj zvezde bi se v fazi rdeče velikanske evolucije razširil precej dlje od trenutne planetarne orbite.

Na podlagi obsežnih numeričnih simulacij, ki jih je izvedel dr. Dimitri Veras z oddelka za fiziko Univerze v Warwicku, ekipa meni, da bi plimovanje zvezdnih planetov morda prineslo planet iz prvotne, širše orbite in ga postavilo tam, kjer ga vidimo danes.

Dr. Veras je dejal: "Ugotovili smo, kako bi lahko ta planet dosegel svojo trenutno lokacijo, in to ne glede na to, ali bi moral planet preživeti zajetje v zvezdnem ovoju rdeče orjaške zvezde. Delo osvetli preživetje planetov, ko njihove starševske zvezde začnejo umirati, in morda celo razkrije nove vidike fizike plime in oseke. & Quot

Soavtor Vardan Adibekyan (IA & amp Universidade do Porto) komentira: »Ta študija je popoln prikaz povezovanja zvezdne in eksplanetarne astrofizike. Zdi se, da zvezdna analiza kaže na to, da je zvezda preveč razvita, da bi še vedno gostila planet na tako "kratki" orbitalni razdalji, medtem ko iz analize eksplanete vemo, da je planet tam!

Adibekyan dodaja: "Rešitev te znanstvene dileme se skriva v" preprostem dejstvu ", da zvezde in njihovi planeti ne samo, da se tvorijo, temveč tudi razvijajo skupaj. V tem konkretnem primeru se je planetu uspelo izogniti zajetju. "

V zadnjem desetletju je asteroseizmologija pomembno vplivala na preučevanje zvezd sončnega tipa in rdečih velikanov, ki kažejo na konvekcijo usmerjena sončna nihanja. Te študije so precej napredovale pri vesoljskih observatorijih, kot sta CoRoT (CNES / ESA) in Kepler (NASA), v naslednjem desetletju pa naj bi se nadaljevale s TESS in PLATO (ESA).

Tiago Campante pojasnjuje, da: "Vključitev IA v TESS je na ravni znanstvenega usklajevanja v Asteroseizmičnem znanstvenem konzorciju TESS (TASC). TASC je obsežno in edinstveno znanstveno sodelovanje, ki združuje vse ustrezne raziskovalne skupine in posameznike z vsega sveta, ki se aktivno ukvarjajo z raziskavami na področju asteroseizmologije. Po stopinjah svojega uspešnega predhodnika, Kepler Asteroseismic Science Consortium (KASC), TASC temelji na sodelovalni in pregledni strukturi delovne skupine, katere namen je olajšati odprto sodelovanje med znanstveniki.

  1. Asteroseizmologija je preučevanje zvezdnih notranjosti z merjenjem potresnih nihanj na površini zvezde. V seizmologiji lahko različne načine vibracij potresa uporabimo za preučevanje notranjosti Zemlje, da dobimo podatke o sestavi in ​​globini različnih plasti. Na podoben način lahko nihanja na površini zvezde uporabimo za sklepanje o notranji strukturi in sestavi zvezde.
  2. Ekipa je: Tiago L. Campante (Instituto de Astrofísica e Ciências do Espaço, Dep. Física e Astronomia Faculdade de Ciências da Universidade do Porto & amp; Kavli Institute for Theoretical Physics, U. California), Enrico Corsaro (INAF | Osservatorio Astrosico di Catania), Mikkel N. Lund (Zvezdni astrofizični center (SAC), Oddelek za fiziko in Astronomija, Inštitut za teoretično fiziko Aarhus U. in amp. Kavli, U. Kalifornija) Benoît Mosser (LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, U. Paris), Aldo Serenelli (Inštitut za vesoljske znanosti (ICE, CSIC) Campus UAB, Institut d'Estudis Espacials de Catalunya (IEEC) in Inštitut za teoretično fiziko amp Kavli, U. Kalifornija), Dimitri Veras (Center za eksplanete in bivalne prostore, Oddelek za fiziko, U. Warwick & amp Kavli Inštitut za teoretično fiziko, U Kalifornija), Vardan Adibekyan (Instituto de Astrofísica e Ciências do Espaço), HM Antia (Tata Institute of Fundamental Research), Warrick Ball (School of Physics and Astronomy, U. Birmingham & amp Stellar Astrophysics Center (SAC), Departman za fiziko in astronomijo, Aarhus U.), Sarbani Basu (Dep. Of Astronomy, Yale U.), Timothy R. Bedding (Sydney Institute for Astronomy (SIfA), School of Physics, U. Sydney, Stellar Astrophysics Center (SAC), Departman za fiziko in astronomijo, Aarhus U. in amp Kavli Institute for Theoretical Fizika, U. Kalifornija) Diego Bossini (Instituto de Astrofísica e Ciências do Espaço), Guy R. Davies (Šola za fiziko in astronomijo, U. Birmingham, Zvezdni astrofizični center (SAC), Oddelek za fiziko in astronomijo, Aarhus U.), Elisa Delgado Mena (Instituto de Astrofísica e Ciências do Espaço), Rafael A. García (IRFU, CEA & amp AIM, CEA, CNRS, U. Paris-Saclay), Rasmus Handberg (Šola za fiziko in astronomijo, U. Birmingham, Zvezdni astrofizični center (SAC), Oddelek za fiziko in astronomijo, Aarhus Marc Hon (School of Physics, U. New South Wales), Stephen R. Kane (Department of Earth and Planetary Sciences, U. California) Steven D. Kawaler (Departman za fiziko in astronomijo, Iowa State U. & amp) Kavli Institute for Theoretical Physics, U. California), James S. Kuszlewicz (Max-Planck-Institut für Sonnensystemforschung & amp Stellar Astrophysics Center (SAC), Oddelek za fiziko in astronomijo, Aarhus U.), Miles Lucas (Oddelek za fiziko in astronomija, zvezna država Iowa) Savita Mathur (Instituto de Astrofsica de Canarias (IAC) in amp U. La Laguna (ULL), oddelek za Astrofsico), Nicolas Nardetto (Azurna obala, Observatoire de la Côte d ' Azur, CNRS, Laboratoire Lagrange) Martin B. Nielsen (Šola za fiziko in astronomijo, U. Birmingham), Zvezdni astrofizični center (SAC), Dep. fizike in astronomije, Aarhus U. & amp. Center za vesoljske znanosti, Inštitut NYUAD, New York U. Abu Dhabi), Marc H. Pinsonneault, Dep. astronomije, Ohio State U., & amp Kavli Institute for Theoretical Physics, U. California), Sabine Reffert & amp Landessternwarte, Zentrum für Astronomie der U. Heidelberg), Víctor Silva Aguirre (Center za astrofiziko zvezd (SAC), Oddelek za fiziko in Astronomy, Aarhus U.) Keivan G. Stassun (Vanderbilt U., odsek za fiziko in astronomijo, Vanderbiltova pobuda za podatkovno intenzivno astrofiziko (VIDA)), Dennis Stello (School of Physics, U. New South Wales, Sydney Institute for Astronomija (SIfA), Fizična šola, U. Sydney, Zvezdni astrofizični center (SAC), Oddelek za fiziko in astronomijo, Aarhus U. in amp Kavli Inštitut za teoretično fiziko, U. Kalifornija), Stephan Stock (Landessternwarte, Zentrum für Astronomie der U. Heidelberg), Mathieu Vrard (Instituto de Astrofísica e Ciências do Espaço) Mutlu Yildiz (Oddelek za astronomijo in vesolje, Prirodoslovna fakulteta, Ege U.), William J. Chaplin (Šola za fiziko in astronomijo, U. Birmingham, Zvezdni astrofizični center (SAC), Oddelek za fiziko in astronomijo, Aarhus Inštitut za teoretično fiziko U. & amp. Kavli, U. Kalifornija), Daniel Huber (Inštitut za astronomijo U. Hawai'i & amp. Kavli Inštitut za teoretično fiziko, U. Kalifornija), Jacob L. Bean (odsek za astronomijo in astrofiziko, U. Chicago), Zeynep Çelik Orhan (oddelek za astronomijo in vesolje, Fakulteta za znanost, Ege U.), Margarida S. Cunha (Instituto de Astrofísica e Ciências do Espaço, Dep. Física e Astronomia Faculdade de Ciências da Universidade do Porto) Jørgen Christensen-Dalsgaard (Zvezdni astrofizični center (SAC), Oddelek za fiziko in astronomijo, Aarhus U. in amp Kavli Inštitut za teoretično fiziko, U. Kalifornija), Hans Ajeldstro (Stellar Center (SAC), Oddelek za fiziko in astronomijo, Aarhus U. & amp; Inštitut za teoretično fiziko in astronomijo, Vilnius U.), Travis S. Metcalfe (Inštitut za vesoljske znanosti, Max-Planck-Institut für Sonnensystemforschung), Andrea Miglio (šola fizike in astronomije, U. Birmingham & amp Stellar Astrophysics Center (SAC), Oddelek za fiziko in astronomijo, Aarhus U.), Mário J. P. F. G. Monteiro (Instituto de Astrofísica e Ciências do Espaço, Dep. Física e Astronomia Faculdade de Ciências da Universidade do Porto), Benard Nsamba (Instituto de Astrofísica e Ciências do Espaço), Sibel Ortel (Oddelek za astronomijo in vesolje, Fakulteta za znanost, Ege U.), Filipe Pereira (Instituto de Astrofísica e Ciências do Espaço), Sérgio G. Sousa (Instituto de Astrofísica e Ciências do Espaço, Dep. Física e Astronomia Faculdade de Ciências da Universidade do Porto), Maria Tsantaki (Instituto de Astrofísica e Ciências do Espaço) in Margaret C. Turnbull (Inštitut SETI, Carl Sagan Center za preučevanje življenja v vesolju)
  3. The Instituto de Astrofísica e Ciências do Espaço (Inštitut za astrofiziko in vesoljske znanosti & ndash IA) je referenčna portugalska raziskovalna enota na tem področju, ki vključuje raziskovalce z Univerze v Lizboni in Univerze v Portu in zajema večino nacionalnih znanstvenih dosežkov na tem področju. V zadnjem vrednotenju raziskovalnih in razvojnih enot, ki ga je opravil Fundação para a Ciência e a Tecnologia (FCT), je bil ocenjen kot & quotExcellent & quot. Dejavnost IA se financira iz nacionalnih in mednarodnih skladov, vključno s FCT / MCES (UID / FIS / 04434/2019).
  4. Članek "TESS Asteroseizmologija znanega gostitelja rdečih velikanov HD 212771 in 203949«Je bil objavljen v Astrofizični časopis (DOI: 10.3847 / 1538-4357 / ab44a8)

30. oktober 2019

Za razgovore kontaktirajte:

Peter Thorley
Vodja odnosov z mediji (Medicinska šola Warwick in Oddelek za fiziko)


Naslov: Kaj lahko asteroseizmologija naredi za eksplanete: Kepler-410A b je majhen Neptun okoli svetle zvezde v ekscentrični orbiti, ki ustreza nizki poševnosti

Kandidata za Keplerjev planet Kepler-410A b (KOI-42b) potrjujemo kot eksoplanet v velikosti Neptuna na 17,8-dnevno ekscentrično orbito okoli svetlega (K = 9,4) zvezda Kepler-410A (KOI-42A). To je tretja najsvetlejša potrjena zvezda gostitelja planeta na Keplerjevem polju in ena najsvetlejših gostiteljev vseh trenutno znanih tranzitnih eksoplanetov. Kepler-410 je sestavljena iz mešanice med hitro vrtljivo zvezdo gostitelja planeta (Kepler-410A) in slabšo zvezdo (Kepler-410B), kar je zapletlo potrditev planetarnega kandidata. Z uporabo asteroseizmologije z uporabo omejitev s krivulje tranzitne svetlobe, prilagodljivo optiko in slikami pik ter opazovanji Spitzerjevega tranzita dokazujemo, da je kandidat lahko le eksoplanet, ki kroži okoli Kepler-410A. Z asteroseizmologijo z visoko natančnostjo določimo naslednje zvezdne in planetarne parametre = 1,221 ± 0,033 M , R = 1,352 ± 0,010 R. , starost = 2,76 ± 0,54 Gyr, planetarni polmer (2,838 ± 0,054 R ) in orbitalna ekscentričnost (0,17). Poleg tega rotacijsko ločevanje načinov pulziranja omogoča merjenje naklona in hitrosti vrtenja Kepler-410A. Naše merjenje naklona 82,5 [°] pomeni nizko poševnost v tem sistemu. Spremembe časa Transitmore in raquo kažejo na prisotnost vsaj enega dodatnega (neprehodnega) planeta (Kepler-410A c) v sistemu. & laquo manj


Kaj se dogaja znotraj te nove spremenljive zvezde?

V eni zvezdasti kopici je bila najdena nova vrsta spremenljive zvezde te vrste, v resnici & # 8212. Astronomi še nimajo imena za tip zvezde, vendar v komentarjih pustite nekaj predlogov!

Za zdaj pa se astronomi sprašujejo, kakšne so posledice za naše razumevanje zvezdne notranjosti.

& # 8220 Že obstoj tega novega razreda spremenljivih zvezd je izziv za astrofizike, & # 8221 je izjavila Sophie Saesen, astronomka iz observatorija v Ženevi, ki je sodelovala v raziskavi.

& # 8220Trenutni teoretični modeli napovedujejo, da se njihova svetloba ne bi smela občasno spreminjati, zato so naša trenutna prizadevanja osredotočena na več informacij o vedenju te čudne nove vrste zvezd. & # 8221

Praskanje po glavi se je začelo, ko so astronomi s teleskopom Evropskega južnega observatorija pogledali v & # 8220Pearl Cluster & # 8221 (NGC 3766), odprto zvezdno kopico, približno 5800 svetlobnih let od Zemlje.

V sedmih letih opazovanja s teleskopom Leonhard Euler (ob rednih meritvah svetlosti) so astronomi opazili 36 zvezd z različnimi obdobji med 2 in 20 urami.

1,2-metrski teleskop Leonhard Euler v Evropskem južnem observatoriju. Zasluge: M. Tewes / ESO

Spremenljive zvezde so znane že stoletja in mnogim od njih sledijo amaterske organizacije, kot je Ameriško združenje spremenljivih opazovalcev. Kolikor najbolje znajo astronomi, zvezde postanejo svetlejše in svetlejše zaradi sprememb v notranjosti & # 8212 zvezdnih vibracij ali & # 8220potresov & # 8221, ki so jih preučevali na področju, imenovanem asteroseizmologija.

Poseben tip spremenljivih zvezd, imenovani spremenljivke Cefeid, lahko zagotovi natančne meritve razdalje, saj imajo vzpostavljeno razmerje med svetilnostjo in obdobjem njihove spremenljivosti.

Preučevanje različnih vrst spremenljivih zvezd je prineslo nekaj spoznanj.

& # 8220Asteroizizmologija zvezd ß Cep [hei] je na primer v zadnjem desetletju odprla vrata za preučevanje njihove notranje rotacije in konvektivnega jedra, & # 8221, so astronomi navedli v prispevku o raziskavi.

Spremembe v svetlosti lahko razlagamo kot vibracije ali nihanja znotraj zvezd s pomočjo tehnike, imenovane asteroseizmologija. Nihanja razkrivajo informacije o notranji zgradbi zvezd, podobno kot seizmologi uporabljajo zemeljske potrese za sondiranje notranjosti Zemlje. Zasluge: Keplerjeva astrozeizmološka ekipa.

Kljub dobro znani naravi spremenljivih zvezd so le malo njih preučevali v odprtih kopicah, kot je NGC 3766.

Razlog je v tem, da potrebujemo veliko časa teleskopa, da si včasih ogledamo zvezdo & # 8212, leta. In čas s teleskopi je drag in dragocen, zato je težko razporediti potreben čas.

& # 8220Zvezdniške kopice so idealno okolje za preučevanje zvezdne spremenljivosti, ker lahko nekatere osnovne lastnosti in evolucijski status posameznih zvezdnih zvezd pridobimo iz lastnosti kopice, & # 8221 so navedli astronomi.

& # 8220Toda zahteva obsežno spremljanje v čim daljšem časovnem obdobju. Ta zahteva lahko pojasni, zakaj doslej ni bilo preučenih veliko grozdov glede na njihovo vsebnost variabilnosti v primerjavi s številom znanih in označenih grozdov. & # 8221

Te posebne zvezde v NGC 3766 pa so bile zmedene.

& # 8220Zvezde so nekoliko bolj vroče in svetlejše od Sonca, sicer pa na videz neopazne, & # 8221 je izjavil ESO, kljub temu pa so imele razlike približno 0,1% običajne svetlosti vsake zvezde.

Cefijska spremenljiva zvezda. Zasluge: vesoljski teleskop Hubble

Možno je, vendar še ni dokazano, da imajo morda zvezde & # 8217 spin nekaj opravka s svetlostjo.

Nekateri opazovani predmeti bivajo s hitrostjo tako hitro, da lahko nekaj materiala odbijejo stran od zvezde in v vesolje, so zapisali astronomi v sporočilu za javnost.

& # 8220 V teh pogojih bo hitro vrtenje pomembno vplivalo na njihove notranje lastnosti, vendar njihovih svetlobnih variacij še ne moremo ustrezno modelirati, & # 8221 je dejala Nami Mowlavi, druga astronomka Ženevskega observatorija, ki je vodila prispevek.

Tudi astronomi tega razreda zvezd še niso poimenovali. Imate kakšno idejo? Za več informacij in oblikovanje predlogov si lahko preberete članek tukaj v Astronomy & amp Astrophysics. Nato lahko svoje misli pustite v komentarjih.


2. Predzgodovina asteroseizmologije

V zadnjih stoletjih so bile najprej odkrite največje svetlobne različice najsvetlejših zvezd. Mira (o Ceti) je bila prva odkrita z opazovanji iz leta 1600 & # x00027s 1. Podroben zgodovinski povzetek opazovanja Mire je podal Hoffleit (1997) za 400-letnico odkritja. Svetlobna spremenljivost & # x003B4 Cep je bil odkrit v osemnajstem stoletju (Goodricke, 1786). Spremenljivost RR Lyrae, skupaj s 64 novimi novoodkritimi spremenljivkami zvezd, je bila objavljena 40 let kasneje (Pickering et al., 1901). Spreminjanje radialne hitrosti & # x003B2 Cephei je opazil Frost (1906). Datum prvega odkritja a & # x003B4 Različice tipa Scuti je težje določiti. Sprememba & # x003B4 Scuti je objavil Fath (1935), v tem letu pa so bile objavljene tudi meritve radialne hitrosti (Colacevich, 1935). Vendar & # x003B4 Zvezde tipa Scuti so kot novo skupino prepoznali šele po nadaljnjih 20 letih (Eggen, 1956). Postopek je jasen, govorimo o novi skupini, če smo našli več zvezd s podobno različico. Merila vključujejo stopnjo variacije in lokacijo zvezde na diagramu Hertzsprung-Russell. V naslednjih letih in desetletjih je bilo odkritih in identificiranih več novih skupin spremenljivih zvezd. Sledil bom, kako se je znanje skupin iz desetletja v desetletje izboljševalo najprej pri zgodnje prepoznanih skupinah in kasneje tudi pri novo opredeljenih skupinah.

Seveda je spremenljivost svetlobe zvezd vzbudila zanimanje teoretičnih fizikov. Številna Eddingtonova dela so se ukvarjala s teorijo pulzacije, ki jo je povzel v knjigi (Eddington, 1926). Napovedal je, da bo spremenljivost svetlobe, ki jo povzroča utripanje zvezd, zagotovila informacije o notranji strukturi, ki jih sicer ne moremo pridobiti. Asteroseizmologija je natančno metoda, pri kateri inverzija spremenljivosti svetlobe zvezde, ki najprej dobi njihovo frekvenčno vsebnost, vodi do fizičnih parametrov znotraj zvezd, tj. Temperature, tlaka, gostote, hitrosti zvoka in kemične sestave vzdolž polmera. . Metoda, imenovana helioseizmology, je v primeru Sonca uspešno delovala. Po drugi strani pa oddaljene zvezde ne delijo zlahka svojih skrivnosti z nami. Določili smo frekvenčno vsebnost številnih zvezd in njihove globalne fizikalne parametre, za zdaj pa za večino vrst pulzirajočih zvezd inverzija še ni bila dosežena, zato odvisnost fizikalnih parametrov od polmera zvezde še ni bila določena, razen za Sonce in kompaktne zvezde.

V nadaljevanju pokažem, kako smo se iz desetletja v desetletje približevali svojemu cilju in koliko sta tehnični razvoj dane starosti in s tem povezana natančnost meritev vplivala na to, kakšne težave so raziskovali prejšnji raziskovalci. Prepričan sem, da lahko poznavanje dela predhodnikov donosno vpliva na današnje raziskave. Ta članek ni popoln pregled vsakega polja utripajočih zvezd, ki bi zahtevalo bolj pravilno strukturo članka. Odločil sem se, da bom svoje življenje uporabil kot vodilo, ko sem bil povabljen, da predstavim svoj pogled na prihodnost asteroseizmologije (še en osebni pregled). Odločil sem se, da bom povzetek začel v obdobju, ko sem se rodil, in znanstveno področje je začelo pritegniti več pozornosti.


Spremenljive zvezde delta Scuti razkrivajo nekatere svoje skrivnosti

Z opazovanji iz satelita NASA TESS je mednarodna skupina raziskovalcev z močno zastopanostjo iz Zvezdnega astrofizičnega centra na univerzi Aarhus preučevala 60 zvezd spremenljivega razreda, poimenovanega po zvezdni delti Scuti v ozvezdju Scutum - Shield. Doslej se je ta razred zvezd izogibal natančnim določitvam njihovih parametrov, ker vibrirajo na zelo zapleten način, kar otežuje njihove raziskave.

Astronomi preučujejo redna nihanja teh vibrirajočih zvezd. Zvezda bo vibrirala kot zvon in tako kot seizmologi preučujejo notranjost Zemlje z opazovanjem valov, ki jih povzročajo detonacije in zemeljski potresi, lahko astronomi prav tako & quot; gledajo & quot; v zvezde s preučevanjem vibracij, opaženih na površini zvezd. Tehnika je bila imenovana & quotasteroseismology & quot.

Čeprav se zvezde delta Scuti v mnogih pogledih obnašajo kot Sonce, članek Nature objavi prvo analizo asteroseizmologov, ki določajo pravilne vzorce frekvenc nihanja pri tej vrsti zvezd. Ti običajni vzorci nihanj zdaj omogočajo primerjavo opazovanih frekvenc s teoretičnimi napovedmi, kar astronomom omogoča, da izvejo več o lastnostih teh zvezd. To bo vplivalo na naše razumevanje, kako zvezde delujejo in kako se sčasoma razvijajo.

Na Soncu imajo frekvence nihanja obdobja, ki trajajo minute. V tipični delta Scuti Star so obdobja dolga ure, toda satelit TESS je odkril druga precej krajša soncu nihanja. Višina oranžne & quotpins & quot kaže, koliko energije vsebuje posamezno nihanje. Ilustracija: HK / SAC / AU.

Sateliti, kot je na primer NASA-in TESS, preučujejo zvezde tako, da v nekaj tednih istočasno izmerijo majhne spremembe svetlosti za deset tisoče zvezd. Če pogledamo vzorce nihanj za navadno & quotwell obnašano & quot; zvezdo, kot je naše Sonce ali ena od rdeče velikanskih zvezd, bo videti lepo in pravilno kot kardiogram iz zdravega srca. Vzorce, ki jih prikazuje večina zvezd Delta del Scuti, bi srčni kirurg začel takoj! V prispevku Nature so raziskovalci ugotovili, da ima 60 od tisoč zvezd delta Scuti, ki jih je opazil TESS, nekaj skupnih lastnosti. Pokažejo redne podobnosti nihanj in ne samo to, ampak so ta nihanja podobna tistim, ki so dobro znana s Sonca. To postavlja astronome na trdna tla:

Profesor Jørgen Christensen-Dalsgaard z univerze v Aarhusu, ki ni soavtor prispevka, je navdušen: & quotZdaj lahko začnemo gledati notranje odnose teh spremenljivih zvezd in tako v teh posebnih okoliščinah izvemo še več podrobnosti v zvezdah. Vsi postajamo modrejši, tudi v vedenju o tem, kako deluje naše bolj vzgojeno Sonce in zakaj je tako razmeroma tiho in stabilno - naučimo nas tudi več o svojem mestu v vesolju. & Quot

Soavtor profesor Hans Kjeldsen z univerze v Aarhusu dodaja: "Nove rezultate lahko med drugim uporabimo za določanje starosti skupin zvezd, ki prihajajo v kopicah in v zvezdnih potokih - zvezde, ki se združujejo, vendar še niso spoznale pravil družbenega oddaljevanja! & Quot

Vodilni avtor novega prispevka v Nature je profesor Tim Bedding, vodja vozlišča SAC v Sydneyju, in pogost gost na univerzi Aarhus. Komentar profesorja Beddinga: »Prej smo našli preveč zmešanih zapiskov, da bi pravilno razumeli te utripajoče zvezde. Bil je nered, kot bi poslušal mačko, ki je hodila po klavirju. " Nadaljuje: »Neverjetno natančni podatki NASA-jeve misije TESS so nam omogočili, da smo presekali hrup. Zdaj lahko zaznamo strukturo, bolj kot poslušanje lepih akordov, ki se igrajo na klavirju. "

Soavtorica dr. Victoria Antoci, ki je zdaj višja raziskovalka v DTU Space, a je bila 8 let raziskovalka na SAC v Aarhusu: "Ti rezultati so fantastični in zelo pomembni in nam bodo omogočili, da bomo bolje razumeli mehanizem, ki poganja te pulzacije, kar se nam je izogibalo 120 let (od zaznavanja prve zvezde delta Scuti)."

Center zvezdne astrofizike (SAC) je ustanovila Danska nacionalna raziskovalna fundacija, pri SAC v Aarhusu pa več astronomov dela na področju asteroseizmologije. Skupina Aarhus je središče večje mreže nacionalnih in mednarodnih sodelavcev & quotnodes & quot. Direktor centra je profesor Jørgen Christensen-Dalsgaard, eden od začetnikov helio- in asteroseizmologije. V prispevku Nature je med 35 avtorji iz 24 raziskovalnih ustanov iz 10 držav več soavtorjev iz Aarhusa in drugih raziskav, povezanih z danskim centrom.

Opažanja, zbrana s sateliti, kot je TESS, se pošljejo Zvezdnemu astrofizičnemu centru na univerzi Aarhus. Tu so surovi podatki pripravljeni za nadaljnje delo in so dostopni številnim astronomom po vsem svetu, ki jih zanima notranja zgradba zvezd. Na ta način ima SAC zadnjih osem let osrednjo mednarodno vlogo na tem raziskovalnem področju.

Kaj je delta Scuti-zvezda?

Zelo veliko zvezd na nebu se zaradi različnih razlogov razlikuje po svetlosti. V določeni prehodni fazi svojega življenja in razvoja se bo večina zvezd začela spreminjati. V ozračjih delta Scuti zvezd je element helij razmeroma bogat in helij je prevladujoči dejavnik spremenljivosti teh zvezd. Ogrevan z energijo iz zvezdne notranjosti, se bo helij ioniziral - torej bo izgubil nekaj svojih elektronov. Hladen helij je neprozoren in ne pušča zvezdne svetlobe skozi vesolje. Ta ujeta svetlobna energija bo ogrevala helij in preostalo zvezdno atmosfero, zaradi česar se ta razširi, ionizira in postane bolj pregledna. Nato bo energija odšla stran, zaradi česar bo zvezda videti svetlejša. Toda s to izgubo energije se zunanje plasti zvezde ohladijo, zaradi česar helij spet postane neprozoren - in postopek se lahko začne znova: zvezda utripa.

Delta Scuti je bil prvi odkrit in je dal ime celotni skupini zvezd. Zvezdo lahko najdete v ozvezdju Scutum - The Shield blizu ozvezdja Aquila na poletnem nebu. Kmalu bo viden v temni in jasni noči s prostim očesom. Če pa gre za spremenljivko, pa so potrebni instrumenti. Njegova velikost se bo v obdobju nekaj več kot 4 1/2 ure spreminjala manj kot 20%. V bližini veliko svetlejša zvezda Altair v Aquili in tudi Denebola v Levu sta veliko bolj znani zvezdi delte Scuti.

Naše Sonce in vse druge zvezde nihajo kot orjaški zvonovi in ​​nihanja povzročajo majhne razlike v celotni svetlosti zvezde. Te variacije je izredno težko izmeriti s površine Zemlje, saj so tako majhne, ​​zato bo treba meritve opraviti s satelitov, kot je npr. CoRot, Kepler in TESS zunaj ozračja. Spreminjajočo se svetlobno krivuljo zvezde lahko pretvorimo v niz nihajnih frekvenc, kot so prizvoki v glasbilu. Te frekvence so značilne za fizične odnose zvezde, vse do njenih osrednjih delov. Tako lahko asterozeizmologi vidijo procese, ki se odvijajo globoko v nedostopnih delih zvezde, in pridobijo znanje o številnih osnovnih parametrih zvezd. Nihanja pa ne povedo celotne zgodbe. Celotno znanje zahteva tudi informacije o površinski temperaturi zvezd in kovinskem vplivu zvezde. Njena opazovanja na Zemlji lahko pomagajo. Vse skupaj nam daje znanje o starosti in velikostih ter številnih drugih fizičnih lastnostih določene zvezde.

PRENESI animacija prikazuje utripajočo delto Scuti-star HD 31901 z zvočno datoteko na tej povezavi.

Ozadje gradiva NASA:

YouTube-vido na satelitu TESS na tej povezavi.

(Univerza v Aarhusu je trenutno zaprta, vendar delamo doma in nas je mogoče kontaktirati)


POVEZANI ČLANKI

"Ker je na gibanje v Indi vplival trk Gaia-Enceladus, se je trk moral zgoditi, ko je zvezda nastala," je povedal Bill Chaplin, profesor astrofizike na univerzi v Birminghamu in vodilni avtor študije.

"Tako smo lahko z asteroseizmično določeno starostjo postavili nove omejitve, kdaj se je zgodil dogodek Gaia-Enceladus."

v Indi ni prišel iz druge galaksije, ampak se je rodil v naši Mlečni poti.

Toda trk Gaia-Enceladus je spremenil svoje gibanje skozi našo Galaksijo.

V Indi nosi značilnosti, da se je zaradi trka ogrel, kar je raziskovalni skupini reklo, da je moralo že obstajati pred združitvijo.

Po novih raziskavah je Rimska pot (na sliki z Zemlje) kanibalizirala galaksijo pred četrtino njene trenutne mase pred približno 11,6 do 13,2 milijardami let.

V Indi je oddaljeno slabih 100 svetlobnih let v ozvezdju Inda, ki so ga Evropejci v 16. stoletju prvič strokovno pregledali.

To je ozvezdje na južni polobli, tako vidno južno od ekvatorja, v državah, kot so Avstralija, Afrika in Južna Amerika.

Znanstveniki verjamejo, da so zvezde, kot je v Indi, "fosilizirani zapisi", ki zaradi dolgotrajnih vibracij prenašajo informacije o okoljih, iz katerih prihajajo.

Astronomi verjamejo, da je naša galaksija Rimske ceste stara približno 13,6 milijarde let.

V svoji življenjski dobi je zaužil veliko manjših galaksij, vendar se je prej izkazalo, da je težko najti natančen čas, v katerem se je katera od teh združitev zgodila.

Researchers now conclude that the galactic merger of Gaia-Enceladus and the Milky Way most likely began as long ago as 13.2 billion years, which in relative terms makes the pre-merger Milky Way short-lived.

‘Because we see so many stars from Gaia-Enceladus, we think it must have had a large impact on the evolution of our galaxy,’ said co-author Dr Ted Mackereth at the University of Birmingham.

‘Understanding that is now a very hot topic in astronomy, and this study is an important step in understanding when this collision occurred.’

Previous studies have revealed a population of stars that were engulfed through the collision of Gaia-Enceladus, which led to pollution of the chemical properties and formation of the Milky Way, including its inner stellar halo and thick disk.

'This study demonstrates the potential of asteroseismology with TESS, and what is possible when one has a variety of cutting-edge data available on a single, bright star,' said Professor Chaplin.

A previous study from last year estimated the collision as about 10 billion years ago, with the Gaia-Enceladus about 25 per cent the size of the current Milky Way before it was swallowed.

This new study, led by the University of Birmingham, used data from NASA’s planet-hunting satellite called Transiting Exoplanet Survey Satellite (TESS), which was launched in 2018 specifically to survey stars outside our solar system.

This was then combined with information from the European Space Agency's (ESA) Gaia mission, which was launched in 2013 to create a three-dimensional map of the Milky Way.

WHAT IS THE EUROPEAN SPACE AGENCY'S GAIA PROBE AND WHAT IS DESIGNED TO DO?

Gaia is an ambitious mission to chart a three-dimensional map of our galaxy, the Milky Way, and in the process reveal its composition, formation and evolution.

Gaia has been circling the sun nearly a million miles beyond Earth's orbit since its launch by the European Space Agency (ESA) in December 2013.

On its journey, the probe has been discreetly snapping pictures of the Milky Way, identifying stars from smaller galaxies long ago swallowed up by our own.

Tens of thousands of previously undetected objects are expected to be discovered by Gaia, including asteroids that may one day threaten Earth, planets circling nearby stars, and exploding supernovas.

Artist's impression of Gaia mapping the stars of the Milky Way. Gaia maps the position of the Milky Way's stars in a couple of ways. It pinpoints the location of the stars but the probe can also plot their movement, by scanning each star about 70 times

Astrophysicists also hope to learn more about the distribution of dark matter, the invisible substance thought to hold the observable universe together.

They also plan to test Albert Einstein's general theory of relativity by watching how light is deflected by the sun and its planets.

The satellite's billion-pixel camera, the largest ever in space, is so powerful it would be able to gauge the diameter of a human hair at a distance of 621 miles (1,000 km).

This means nearby stars have been located with unprecedented accuracy.

Gaia maps the position of the Milky Way's stars in a couple of ways.

Gaia’s all-sky view of our Milky Way Galaxy and neighbouring galaxies, based on measurements of nearly 1.7 billion stars. The map shows the total brightness and colour of stars observed by the ESA satellite in each portion of the sky between July 2014 and May 2016. Brighter regions indicate denser concentrations of especially bright stars, while darker regions correspond to patches of the sky where fewer bright stars are observed. The colour representation is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky.

It pinpoints the location of the stars but the probe can also plot their movement, by scanning each star about 70 times.

This is what allows scientists to calculate the distance between Earth and each star, which is a crucial measure.

In September 2016, ESA released the first batch of data collected by Gaia, which included information on the brightness and position of over a billion stars.

In April 2018, this was expanded to high-precision measurements of almost 1.7 billion stars.


Secret of Ancient Galaxy Merger Revealed by Studies of a Lone Star

Astronomers believe that our Milky Way galaxy, approximately 13.6 billion years old, has ingested many smaller galaxies over its lifetime, however, it has previously proved difficult to determine the precise time at which these mergers occurred.

A star visible from Earth with the naked eye has revealed a fascinating story dating at least that our Milky Way swallowed up a smaller galaxy at least 11.6 billion years ago, according to a study recently published in Nature.

Main author of the paper "Age dating of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi" is Bill Chaplin of Birmingham University. He and a list of co-authors, affiliated with the Stellar Astrophysics Centre (SAC) at Aarhus University, Resorted to a novel approach by applying the forensic characterisation of a single ancient, bright star called ν Indi to probe the history of the Milky Way.

The new study used data from NASA’s planet-hunting satellite called Transiting Exoplanet Survey Satellite (TESS), which was launched in 2018 to survey stars outside our solar system, and augmented it with data from the European Space Agency's (ESA) Gaia mission, which was launched in 2013, to create a three-dimensional map of the Milky Way.

The research revealed a population of stars accreted after the collision of a dwarf galaxy, called Gaia–Enceladus1. The impact had resulted in “pollution” of the chemical and dynamical properties of the Milky Way.

The team measured oscillations of ν Indi, which is viewable from the Southern Hemisphere and used the results to date the collision between the Milky Way and another dwarf galaxy.

ν Indi, according to research, was born early in the life of the Milky Way, but after its impact with the galaxy – named Gaia-Enceladus – it was pushed from its original orbit in the Halo of the Milky Way into a dramatically altered trajectory.

He added: “That is how we have been able to use the asteroseismically-determined age to place new limits on when the Gaia-Enceladus event occurred.”

Astronomers believe our Milky Way swallowed Gaia-Enceladus somewhere between 11.6 billion and 13.2 billion years ago - after ν Indi was formed, since the star carries traces of having been heated by the collision.

A previous study, in 2019, had estimated the impact as about 10 billion years ago.

V Indi is estimated to be just under 100 light years away, in the constellation of Indus, and as a southern hemisphere constellation is visible south of the equator, in countries such as Australia, Africa and South America.

Research typically regards stars like v Indi as “fossilised records” of information about their past due to their long-lasting vibrations.
Astronomers claim that our own Milky Way galaxy, estimated to be 13.6 billion years old, has swallowed up many smaller galaxies. However the dating of these collisions proved to be challenging.

Researchers now conclude that the galactic merger of Gaia-Enceladus and the Milky Way most likely began as long ago as 13.2 billion years, which in relative terms makes the pre-merger Milky Way short-lived.

“Understanding that is now a very hot topic in astronomy, and this study is an important step in understanding when this collision occurred.”

Professor Chaplin also pointed to the potential of asteroseismology with TESS, and hailed today’s variety of cutting-edge data available on “a single, bright star”.

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NASA Kepler Reaching into the Stars
04.12.11

An artist’s rendering that compares the approximate size and color of the stars in the triple-eclipsing system HD 181068. Click image for full-resolution.
An artist’s rendering that compares the approximate size and color of the stars in the triple-eclipsing system HD 181068.
Image credit: NASA/KASC

We are entering a golden era for “stellar physics” – a term coined to describe research about the formation, evolution, interior and the atmospheres of stars. Thanks to a partnership forged among stellar astrophysics, scientists and NASA’s Kepler Mission, a goldmine of data is now available to support the world’s efforts to detect planets in the habitable zone around other stars.

The Kepler photometric data is a measurement of light’s “brightness,” and provides an unprecedented opportunity for the emerging field of asteroseismology, the study of the internal structure of stars by observing minuscule pulsations in the star brightness. Asteroseismic research is giving insights into the fundamental properties of stars, including their mass, size, age and internal structure. Kepler enables studies of a large number of stars representing a broad range of types. This asteroseismic research will substantially improve our understanding of stellar evolution. It also will help determine the properties of stars that have planetary systems studied in the Kepler exoplanet program.

The Kepler Asteroseismic Science Consortium (KASC) pushes the envelope in this field of study. Using the unparalleled precision and quality of Kepler data, the KASC research is contributing to stellar astrophysics in profound ways. The consortium is comprised of more than 400 scientists and is led by the Danish Asteroseismology Centre in the Department of Physics and Astronomy at the University of Aarhus, Denmark.

The KASC recently presented new findings published in three papers in the journal Science. In combination, these latest results illustrate the power of the Kepler Space Telescope to probe the internal structure of distant stars.

Kepler Listens to an Orchestra of Sun-like Stars to Tune the Galactic Models

The scientific investigation of sun-like stars has taken a major step forward thanks to the Kepler Mission. In addition to searching for exoplanets, it is providing exquisite data on stellar oscillations.

“The sound inside the stars makes them ring or vibrate like musical instruments,” said Bill Chaplin from the University of Birmingham’s School of Physics and Astronomy, the lead author of this paper. “If you measure the pitch of the notes produced by an instrument it can tell you how big the instrument is. The bigger the instrument is, the lower the pitch and deeper the sound. This is how we can tell how big a star is – from its stellar music.”

Oscillation measurements are used to accurately determine fundamental stellar properties like mass, size, and age. This is where theory meets observation. Scientists can synthesize a snapshot of our galaxy and all the stars it contains using models based on everything we know about how much raw material there is in our galaxy for building stars, what types of stars are made, how they evolve with time, and how long they live. They can then compare the properties of stars in this synthetic snapshot with the properties of the sun-like stars in the asteroseismic survey. In essence, the team has taken a census and compared it to predictions, and found that the sizes of the stars are consistent with the predictions, but the masses are not. The asteroseismic survey suggests that the number of low mass stars is slightly larger than expected. This work sends theoreticians back to refine their models and will ultimately lead to a better understanding of the structure and evolution of stars in our galaxy.

“Before Kepler we had asteroseismic data on only about 20 such stars – We now have an orchestra of stars to play with,” said Hans Kjeldsen from Aarhus from the Danish Asteroseismology Centre in Aarhus, who coordinates KASC. “This opens up huge possibilities for probing stellar evolution and obtaining a clearer picture of the past and future of our own sun and how our galaxy, and others like it, has evolved over time. We can, for example, pick out stars that have the same mass of the sun but have different ages, to, in effect, follow the sun in time.”

To read the full paper in Science, visit: Ensemble Asteroseismology of Solar-type Stars with the NASA Kepler Mission, by W. J. Chaplin et al, Science 8 April 2011: 213-216. [DOI:10.1126/science.1201827]

Astronomers Detect Echoes from the Depth of a Red Giant Star

An international team of astronomers reports the unexpected discovery of waves inside a star that travel so deep that they reach the core. Waves traversing stars, similar to sound waves here on Earth, were already known to exist, but until now only waves traveling the outer part of the star, or as deep as hundreds of thousands of kilometers, were detected. At a certain depth, the stellar material is too dense for waves to penetrate so they bounce back to the surface. The detection of waves that reach the star’s core reveal conditions that open a window to an inferno that otherwise would remain unreachable and hidden. The discovery was made in a red giant star, an elderly star, similar to what our sun will become in about 5 billion years.

“Having a view into the core of these red giants will teach us exactly what will happen to our sun when it grows older,” said Paul Beck, a PhD student at Leuven University in Belgium.

To read the full paper in Science, visit: Kepler-Detected Gravity-Mode Period Spacings in a Red Giant Star, by P.G. Beck et al, Science 8 April 2011: 180-181. [DOI: 10.1126/science.1203887]

Kepler Discovery of a Unique Triply Eclipsing Triple Star

Aliz Derekas of Eotvos University and Konkoly Observatoryin Budapest, Hungary, used Kepler data to learn more about a unique three-star system known as HD 181068, which the authors named ‘Trinity.’ The triple system is comprised of two red dwarfs orbiting each other and simultaneously orbiting a more distant red giant star that is 12.4 times larger than our sun (figure 1). These systems are important for testing theories of star formation and evolution. While triple systems are not uncommon, this particular triple system is oriented perfectly to make the red dwarfs and the red giant regularly eclipse each other. The surface brightness of the three stars are very similar, so just as a white rabbit is camouflaged in snow, when the red dwarfs are in front of the red giant, their eclipses are nearly undetectable. Careful analyses of red giant stars observed by Kepler have shown that they exhibit oscillations similar to those in the sun. Trinity’s red giant star does not. This would indicate a mysterious mechanism that suppresses the pulsation.

“Surprisingly, we do detect some variability but with periods that are closely linked to the orbital period of the close pair in the system,” said Derekas. “This may indicate that tidal forces of the close pair induce vibrations in the red giant. The intriguing nature of this unique system remained unnoticed until now despite the fact that it is nearly bright enough to be visible to the naked eye. We really needed Kepler with its unprecedentedly precise and uninterrupted photometric monitoring to uncover such a rare gem,” she added.

To read the full paper in Science, visit: A Red Giant in a Triply-Eclipsing Compact Hierarchical Triple System, by Derekas et al, Science 8 April 2011: 216-218. [DOI:10.1126/science.1201762]

To listen to an interview with Michael Montgomery, University of Texas at Austin, as he discusses Kepler’s observations and what they reveal about the internal structure of distant stars, visit: Science Podcast.

Michele Johnson, Public Affairs Officer, Kepler Mission
Ames Research Center, Moffett Field, Cali


Backgrounder: MOST Scientists Unpack A Suitcase Full of Space Science

The MOST Canadian space telescope was launched from northern
Russia in June 2003 aboard a former Soviet ICBM (Intercontinental
Ballistic Missile) converted to peaceful use. Weighing only
54 kg, this suitcase-sized microsatellite is packed with a
small telescope and electronic camera to study stellar variability.

One of its early targets was the star eta Bootis, a slightly
more massive and younger version of the Sun. Astronomers had
picked out this star as one of the best candidates for the
new technique of “asteroseismology” — using surface
vibrations to probe the inside of a star, similar to how geophysicists
use earthquake vibrations to probe the Earth’s core.

MOST monitored eta Bootis for 28 days without interruption,
placing the star under a 24-hour scientific ‘stake-out’
that revealed behaviour that was hidden from the limited view
possible for Earth-bound telescopes. Accumulating almost a
quarter of a million individual measurements of this star,
MOST reached a level of light-measuring precision at least
10 times better than the best ever achieved before from Earth
or space.

The data reveal the star is vibrating, but at a pitch well
below the range of human hearing. The stellar melody should
allow the MOST team of scientists, including Dr. David Guenther
of the Canadian Institute for Computational Astrophysics at
St. Mary’s University, Halifax, to determine the age
and structure of eta Bootis. “We’re now in a position
to explore new physics in stars, with observations like these,”
said Dr. Guenther.

Before observing eta Bootis, while still in the shakedown
phase of its mission, MOST was aimed for testing purposes
at a fainter star called kappa 1 Ceti. Astronomers already
suspected this was a younger version of our Sun, with an age
of about 750 million years. The Sun’s age is about 4.5
billion years, and it’s just entering middle age. V
terms of a human life, the Sun would be about 45 years old
while kappa 1 Ceti would be eight years old – barely
a pre-teen.

Like many human kids, Kappa 1 Ceti is hyperactive, flaring
up from time to time, and spinning with much more kinetic
energy than sedate older stars like the Sun. It also has a
severe case of acne — dark spots on its face which are much
larger than those visible on the Sun’s surface. The MOST data,
following Kappa 1 Ceti for 29 days, show in exquisite detail
how the spots move across the visible side of the star as
it spins once every nine days or so. And because a star is
not solid, different parts of its gaseous surface spin at
different rates. MOST has been able to measure this effect
directly in a star other than the Sun for the first time.
These results are being prepared for submission to The Astrophysical
Journal.

Future targets for MOST include other stars representing
the Sun at various stages in its life, and stars known to
have giant planets. MOST is designed to be able to register
the tiny changes in brightness that will occur as a planet
orbits its parent star. The way in which the light changes
will tell astronomers about the atmospheric composition of
these mysterious worlds, and even if they have clouds.

“It’s like doing a weather report for a planet
outside our Solar System,” says Dr. Jaymie Matthews,
MOST Mission Scientist, of the University of British Columbia.


Deaf Students Feel the Universe's Vibrations in New Workshop

Students experienced the vibrations of Earth's auroras, the Sun's flares, Jupiter's bow shock and Saturn's rings in an outreach activity designed specifically for their community.

The workshop activity took the students on a journey from Earth outward to the edges of the Solar System and beyond with 19 different vibrations, included of the aurorae. Credit: Johannes Groll/Unsplash

A new workshop brought the vibrations of the universe to deaf students, a group that is often overlooked in informal outreach activities. Astronomers and teachers at a school for deaf children partnered to design an activity that transforms cosmic phenomena into vibrations that students can feel and can connect with visuals and a scientific narrative.

“It’s the beginning of trying to think of scientific outreach with a much broader appeal, where everyone is capable and must have access to public outreach of science,” Mario De Leo-Winkler, an astronomer and director of the National System of Researchers of Mexico, told Eos.

When he began looking into astronomy outreach activities for people with physical disabilities, De Leo-Winkler found that there were many activities designed for blind people who could not see the stars but none designed specifically for the deaf community.

“We all like the stars,” he said. “If that was enough – if looking through a telescope or interacting with things related to science or to astronomy in general was enough – then we would all be scientists or we would all be astronomers. You need an extra push as a citizen to be enticed or enamoured with science.”

Making astronomy data vibrate

According to recent surveys, over 5% of the world’s population are deaf or hard of hearing, but this community represents only about 1% of recently awarded science and engineering doctorate degrees. This is partly due to the scarcity of deaf-accessible science, technology, engineering, and mathematics (STEM) courses in higher education, De Leo-Winkler explained. “If you add to that that there is no specific push toward scientific vocations in the Deaf community, then we have a problem,” he said.

De Leo-Winkler and other astronomers at the University of California, Riverside, decided to create their own outreach activity in partnership with the California School for the Deaf, Riverside (CSDR). The team decided to focus on developing an activity that uses the sense of touch to convey information. Research into brain development has shown that in people who are born deaf or who lose hearing later in life, the brain rewires itself to process vibrations in the absence of sound through a phenomenon known as neuroplasticity.

The team gathered recordings of Earth and astronomical phenomena that produce distinct sounds or that vary with time. For data that were outside the range of human hearing – about 20-20,000 hertz – the team used an algorithm to shift the sounds into that range.

For nonauditory data sets, the researchers used a technique called sonification to transform the data into sounds and vibrations the students could experience.

CSDR teachers gave their expertise and guidance to the astronomers when selecting sounds that would produce detectable and distinguishable vibrations. They also developed American Sign Language (ASL) interpretations for unfamiliar astronomy terms in the accompanying narrative.

The team held the workshop in a multisensory sound lab at CSDR. The lab converts sound into other mediums, such as vibrations and light, that can be experienced by deaf individuals.

“We’re giving the explanation, we’re showing the imagery, and we’re producing the vibrations at the same time,” De Leo-Winkler said.

Vibrations of the universe

The researchers held two workshops in the multisensory sound lab for CSDR students in grades 3-8. They collected feedback from participants after the first workshop and altered their set of vibrations, visual materials, and verbal and ASL narratives in the second workshop in response to that feedback.

The students first learned some introductory astronomy in their classrooms before participating in the workshop. The workshop presenter then introduced students to the idea that sounds and vibrations are connected and gave examples that students might be familiar with, like thunderstorms or bubbling pots of water.

The presenters explained that everything in the universe produces energy and that energy can be converted into sounds or vibrations that they could feel.

The workshop activity took the students on a journey from Earth outward to the edges of the Solar System and beyond with 19 different vibrations. Some of the vibrations they experienced include Earth’s auroras, the vibrations of the Sun and radio emissions from Saturn recorded by the Cassini spacecraft. Eighty-three students participated in the two workshop stages and provided overall positive feedback about the experience. The team analysed the survey responses and published the results earlier this month in the Journal of Science Education and Technology.

Opening the door

This workshop focused on astronomy phenomena, but the techniques could easily be adapted to other STEM disciplines, such as physics, stem cell research, or genome mapping, De Leo-Winkler said.

“I think the possibilities are limitless,” he said, “as long as you have a clear interpretation of the information that you want to transfer to the students and as long as it’s fun.”

The team has made all of its sound files and presentation materials freely available online.

“We’re opening the door for others to be able to explore for themselves what has been done and to think out of the box,” De Leo-Winkler said. “We invite people to take it in, to use it, to reimagine it, and to follow some of the steps and create new and innovative things.”

This article was first published on Eos and has been republished under a Creative Commons license. Read the original here.