Close Look at Young Star Finds a Chemical Surprise

first_imgThe basics of star formation are easy. Find an unusually dense region within a molecular cloud filled with dust and gas in interstellar space and let gravity do the rest. The gas and dust will eventually coalesce into a doughnut-shaped envelope that encircles an inner rotating disk. As material accumulates over hundreds of thousands of years, the central region collapses into a star while the disk solidifies into planets.Astronomers have understood this overall scenario for decades, but the details are fuzzy because telescopes haven’t been good enough to check theorists’ computer models. That changed in 2011 with the partial completion of the Atacama Large Millimeter/submillimeter Array (ALMA). The collection of radio antennas is being erected on the Chajnantor Plain, 5000 meters above sea level in the Chilean Andes, where the dry, sparse air causes minimal distortion of the faint waves from the far reaches of the universe. Using 24 of the antennas—the final array will have 66—an international group led by astrophysicists at the University of Tokyo, has taken the most detailed look yet at the heart of a star-forming region and found a chemical surprise.The researchers trained ALMA on a very young star still forming in the constellation Taurus, about 450 light-years from Earth. As is typical at such an early stage, the star is encircled by an envelope and disk of gas and dust. The new scope’s power enabled the team to identify the chemical composition of the gases at different locations throughout this star- and planet-forming system. Previously, astronomers thought that the envelope and disk must be made up of the same gaseous molecules of hydrogen found throughout interstellar space plus dust particles made up of other elements. To the surprise of the University of Tokyo group, ALMA detected something different—sulfur monoxide gas—in a narrow band where the envelope meets the disk. Collisions between particles in the envelope and those in the rapidly spinning disk generate heat that thaws frozen sulfur monoxide molecules stuck to dust grains, explains Nami Sakai, an astrophysicist at the University of Tokyo. Sulfur monoxide can’t be detected when it is frozen to dust grains. But ALMA can spot it in its gaseous state. Knowing just what gases are swirling around young stars should lead to a better understanding of where and how elements found in planets, comets, and asteroids are formed. Sakai and colleagues report their findings online today at Nature.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)”These are beautiful data and very interesting results,” says Ewine van Dishoeck, an astrophysicist at the Leiden Observatory in the Netherlands. “This work shows that ALMA will provide ample observational evidence” that will challenge theoretical models, adds astrophysicist Stéphane Guilloteau of University of Bordeaux in France. “This paper is a beautiful example of the new discovery [capabilities] offered by ALMA.”last_img read more

Continue reading

Sanjay Manjrekar backs Sourav Ganguly in rift against Ravi Shastri

first_imgFormer India cricketer Sanjay Manjrekar has picked his side in the duel between former India Team Director Ravi Shastri and BCCI’s Cricket Advisory Committee member Sourav Ganguly. Shastri, in an exclusive interview with India Today’s Rajdeep Sardesai on Tuesday, lashed out at Ganguly by calling him ‘disrespectful’ for not being present when Shastri was presenting his case for the coaching job of the Indian cricket team. (Shastri shouldn’t have been holidaying in Bangkok, Ganguly hits back)Shastri’s former India and Mumbai teammate Manjrekar has now come out in support of Ganguly and said that it was probably the coaching snub which Shastri could not handle. (Shastri-Ganguly rift horrible news for Indian cricket)More than Sourav, I think Ravi is miffed with the rejection. It’s a new experience for him. BCCI have made the better choice as coach. Sanjay Manjrekar (@sanjaymanjrekar) June 29, 2016Manjrekar also said that the CAC, which also consisted of cricket legends Sachin Tendulkar and VVS Laxman, had taken the correct decision by choosing Anil Kumble as the head coach of the Indian team. (Ganguly’s absence was disrespectful: Shastri to India Today)The Indian cricket team now has a coach who will put his heart & soul in the job. Anil Kumble knows no other way of working. Sanjay Manjrekar (@sanjaymanjrekar) June 23, 2016Ganguly himself broke his silence on the issue and gave Shastri a piece of his mind in a scathing interview to India Today on Wednesday.last_img read more

Continue reading