J/MNRAS/500/889ivo://CDS.VizieR/J/MNRAS/500/889CDSAguado D.S.Myeong G.C.Belokurov V.Evans N.W.Koposov S.E.,Allende Prieto C.Lanfranchi G.A.Matteucci F.Shetrone M.Sbordone L.,Navarrete C.Gonzalez Hernandez J.I.Chaname J.Peralta de Arriba L.,Yuan Z.2024-03-04T13:11:11Z2023-11-09T08:53:18ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frhalo-starsdwarf-galaxiesmilky-way-galaxymetallicitychemically-peculiar-starseffective-temperaturevisible-astronomyspectroscopyThe S2 stream is a kinematically cold stream that is plunging downwards through the Galactic disc. It may be part of a hotter and more diffuse structure called the Helmi stream. We present a multi-instrument chemical analysis of the stars in the metal-poor S2 stream using both high- and low-resolution spectroscopy, complemented with a re-analysis of the archival data to give a total sample of 62 S2 members. Our high-resolution program provides {alpha}-elements (C, Mg, Si, Ca, and Ti), iron-peak elements (V, Cr, Mn, Fe, Ni), n-capture process elements (Sr, Ba), and other elements such as Li, Na, Al, and Sc for a subsample of S2 objects. We report coherent abundance patterns over a large metallicity spread (~1dex) confirming that the S2 stream was produced by a disrupted dwarf galaxy. The combination of S2's {alpha}-elements displays a mildly decreasing trend with increasing metallicity, which can be tentatively interpreted as a 'knee' at [Fe/H]<-2. At the low-metallicity end, the n-capture elements in S2 may be dominated by r-process production; however, several stars are Ba-enhanced but unusually poor in Sr. Moreover, some of the low-[Fe/H] stars appear to be carbon-enhanced. We interpret the observed abundance patterns with the help of chemical evolution models that demonstrate the need for modest star formation efficiency and low wind efficiency confirming that the progenitor of S2 was a primitive dwarf galaxy.2021MNRAS.500..889Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/500/889CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)V/146 : LAMOST DR1 catalogs (Luo+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/500/889https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/500/889http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/500/889https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/500/889https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/500/889http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/500/889GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/500/889/tableb1 (Coordinates and stellar parameters from low-resolution analysis)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/500/889/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/500/889/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/500/889/tableb1?GETtext/xml+votable180.050000true1.1547917-4.70911110.005555555555555556Cone search capability for table J/MNRAS/500/889/tableb2 (APOGEE abundances for S2 members from ASPCAP)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/500/889/tableb2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/500/889/tableb2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/500/889/tableb2?GETtext/xml+votable180.050000true41.3708589-1.01501080.0055555555555555566/897 4279 4542 4836 4903 4947 5037 5356 5579 5784 5880 5917 5972 6450 9162 9164 9924 10252 10312 10409 10522 12578 16115 17241 17244 17316 17362 17369-17370 17518 17746 17769 17829 17894 18020 18067 18075 18169 18775 18777 18801 19536 19727 19738 19761 22951 23193 26172 26253 27071 27077 27814 27904 27983 28073 28420 28464 28580 32482https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/500/889?format=asciiOpticaldefaultJ/MNRAS/500/889/tableb1Coordinates and stellar parameters from low-resolution analysisNameSource name (JHHMM-DDMM)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSurveySurvey name (SDSS or LAMOST)meta.idcharVmagV-band magnitudemagphot.mag;em.opt.VfloatRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainTeffEffective temperatureKphys.temperature.effectiveinte_TeffError on TeffKstat.error;phys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggError on logglog(cm.s**-2)stat.errorfloat[Fe/H]Fe/H abundance ratiophys.abund.Fe;arith.ratiofloate_[Fe/H]Error on [Fe/H]stat.error;phys.abund.Fefloat[C/Fe]C/Fe abundance ratiophys.abund;arith.ratiofloate_[C/Fe]Error on [C/Fe]stat.error;phys.abundfloatS/NSignal to noise ratiostat.snrintFlagFlag (1)meta.codecharSimbadNameSimbad column added by the CDSmeta.idcharnullableJ/MNRAS/500/889/tableb2APOGEE abundances for S2 members from ASPCAPrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameAPOGEE name (2MHHMMSSss+DDMMSSs)meta.id;meta.maincharTeffEffective temperatureKphys.temperature.effectiveinte_TeffError on TeffKstat.error;phys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloatSimbadSimbad column added by the CDSmeta.ref.urlcharFlag? Flag (1)meta.codeintnullablee_loggError on logglog(cm.s**-2)stat.errorfloat[Fe/H]Fe/H abundance ratiophys.abund.Fe;arith.ratiofloate_[Fe/H]Error on [Fe/H]stat.error;phys.abund.Fefloat[C/Fe]C/Fe abundance ratiophys.abundfloate_[C/Fe]Error on [C/Fe]stat.error;phys.abundfloat[Mg/Fe]Mg/Fe abundance ratiophys.abundfloate_[Mg/Fe]Error on [Mg/Fe]stat.error;phys.abundfloat[Al/Fe]Al/Fe abundance ratiophys.abundfloate_[Al/Fe]Error on [Al/Fe]stat.error;phys.abundfloat[Si/Fe]Si/Fe abundance ratiophys.abundfloate_[Si/Fe]Error on [Si/Fe]stat.error;phys.abundfloat[Ca/Fe]Ca/Fe abundance ratiophys.abundfloate_[Ca/Fe]Error on [Ca/Fe]stat.error;phys.abundfloat[Mn/Fe]? Mn/Fe abundance ratiophys.abundfloatnullablee_[Mn/Fe]? Error on [Mn/Fe]stat.error;phys.abundfloatnullable[Ni/Fe]? Ni/Fe abundance ratiophys.abundfloatnullablee_[Ni/Fe]? Error on [Ni/Fe]stat.error;phys.abundfloatnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main