J/MNRAS/440/2665 SDSS J021933.13+200830.2 spectroscopy (Roederer+, 2014)
Detailed abundance analysis of the brightest star in Segue 2,
the least massive galaxy.
Roederer I.U., Kirby E.N.
<Mon. Not. R. Astron. Soc., 440, 2665-2675 (2014)>
=2014MNRAS.440.2665R 2014MNRAS.440.2665R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Spectroscopy
Keywords: nuclear reactions, nucleosynthesis, abundances - stars: abundances -
stars: individual: SDSS J021933.13+200830.2 -
galaxies: individual: Segue 2
Abstract:
We present the first high-resolution spectroscopic observations of one
red giant star in the ultra-faint dwarf galaxy Segue 2, which has the
lowest total mass (including dark matter) estimated for any known
galaxy. These observations were made using the Magellan Inamori
Kyocera Echelle (MIKE) spectrograph on the Magellan II Telescope at
Las Campanas Observatory. We perform a standard abundance analysis of
this star, SDSS J021933.13+200830.2, and present abundances of 21
species of 18 elements as well as upper limits for 25 additional
species. We derive [Fe/H]=-2.9, in excellent agreement with previous
estimates from medium-resolution spectroscopy. Our main result is that
this star bears the chemical signatures commonly found in field stars
of similar metallicity. The heavy elements produced by neutron-capture
reactions are present, but they are deficient at levels characteristic
of stars in other ultra-faint dwarf galaxies and a few luminous dwarf
galaxies. The otherwise normal abundance patterns suggest that the gas
from which this star formed was enriched by metals from multiple Type
II supernovae reflecting a relatively well-sampled IMF. This adds to
the growing body of evidence indicating that Segue 2 may have been
substantially more massive in the past.
Description:
Observations were made with the Magellan Inamori Kyocera Echelle
(MIKE) spectrograph on the 6.5 m Landon Clay Telescope (Magellan II)
at Las Campanas Observatory.
Objects:
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RA (ICRS) DE Designation(s)
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02 19 33.14 +20 08 30.3 SDSS J021933.13+200830.2 = 2MASS J02193313+2008303
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 46 257 Atomic data, equivalent widths, and derived
abundances
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- ID Species (1)
7- 13 F7.2 0.1nm Wave Wavelength
15- 18 F4.2 eV ExPot Excitation potential
20- 24 F5.2 --- loggf Log of degeneracy times oscillator strength
26- 27 I2 --- Ref Literature reference for loggf (2)
29- 33 F5.1 10-13m EW ? Equivalent width
35 A1 --- l_logeps ? Upper limit flag on logeps
37- 41 F5.2 [-] logeps Log epsilon abundance
43- 46 F4.2 [-] e_logeps ? Error on log epsilon abundance
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Note (1): Entries for CH and CN molecules have been omitted from this
machine-readable table and are hereafter (from printed version):
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Species Band Ref logeps
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C (CH) A2Δ-X2Π G band 2 4.85±0.20
N (CN) B2Σ-X2Σ violet band 3 <6.85
N (CN) A2Σ-X2Σ red band 3 <9.00
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Note (2): References as follows:
1 = Smith, Lambert, & Nissen (1998ApJ...506..405S 1998ApJ...506..405S) for both log gf value
and 7Li hfs
2 = B. Plez 2007, private communication
3 = Kurucz & Bell (1995, Kurucz CD-ROM. Smithsonian Astrophysical
Observatory. Cambridge, MA)
4 = Fuhr & Wiese (2009, Atomic Transition Probabilities. Handbook of
Chemistry and Physics. 90th edn. Lide D. R., editor. Boca Raton, FL:
CRC Press, Inc., p. 10)
5 = Chang & Tang (1990, J. Quant. Spectrosc. Rad. Trans., 43, 207)
6 = Aldenius et al. (2007A&A...461..767A 2007A&A...461..767A)
7 = Aldenius, Lundberg, & Blackwell-Whitehead (2009A&A...502..989A 2009A&A...502..989A)
8 = Lawler & Dakin (1989, J., Opt., Soc., Am., B Optical Phys., 6, 1457),
using hfs from Kurucz & Bell (1995, Kurucz CD-ROM. Smithsonian
Astrophysical Observatory. Cambridge, MA)
9 = Lawler et al. (2013ApJS..205...11L 2013ApJS..205...11L)
10 = Pickering, Thorne, & Perez (2001ApJS..132..403P 2001ApJS..132..403P), with corrections given
in Pickering, Thorne, & Perez (2002, ApJS, 138, 247)
11 = Wood et al. (2013, Cat. J/ApJS/208/27)
12 = Doerr et al. (1985, J. Quant. Spectrosc. Rad. Trans., 33,55), using hfs
from Kurucz & Bell (1995, Kurucz CD-ROM. Smithsonian Astrophysical
Observatory. Cambridge, MA)
13 = Biemont et al. (1989A&A...209..391B 1989A&A...209..391B)
14 = Sobeck, Lawler, & Sneden (2007, Cat. J/ApJ/667/1267)
15 = Nilsson et al. (2006A&A...445.1165N 2006A&A...445.1165N)
16 = Den Hartog et al. (2011. Cat. J/ApJS/194/35) for both log gf value
and hfs
17 = O'Brian et al. (1991, J., Opt., Soc., Am., B Optical Phys, 8, 1185)
18 = Nitz et al. (1999ApJS..122..557N 1999ApJS..122..557N), using hfs from Kurucz & Bell (1995,
Kurucz CD-ROM. Smithsonian Astrophysical Observatory. Cambridge, MA)
19 = Fuhr & Wiese (2009, Atomic Transition Probabilities. Handbook of
Chemistry and Physics. 90th edn. Lide D. R., editor. Boca Raton, FL:
CRC Press, Inc., p. 10), using hfs from Kurucz & Bell (1995,
Kurucz CD-ROM. Smithsonian Astrophysical Observatory. Cambridge, MA)
20 = Roederer & Lawler (2012, Cat. J/ApJ/750/76)
21 = Biemont et al. (2011MNRAS.414.3350B 2011MNRAS.414.3350B)
22 = Ljung et al. (2006A&A...456.1181L 2006A&A...456.1181L)
23 = Palmeri et al. (2005MNRAS.363..452P 2005MNRAS.363..452P)
24 = Fuhr & Wiese (2009, Atomic Transition Probabilities. Handbook of
Chemistry and Physics. 90th edn. Lide D. R., editor. Boca Raton, FL:
CRC Press, Inc., p. 10), using hfs/IS from
McWilliam (1998AJ....115.1640M 1998AJ....115.1640M) when available
25 = Lawler, Bonvallet, & Sneden (2001ApJ...556..452L 2001ApJ...556..452L), using hfs from
Ivans et al. (2006, Cat. J/ApJ/645/613)
26 = Lawler et al. (2009, Cat. J/ApJS/182/51)
27 = Li et al. (2007, J. Phys. Scr., 76, 577) using hfs from
Sneden et al. (2009, Cat. J/ApJS/182/80)
28 = Den Hartog et al. (2003ApJS..148..543D 2003ApJS..148..543D), using hfs/IS from
Roederer et al. (2008ApJ...675..723R 2008ApJ...675..723R) when available
29 = Lawler et al. (2006, Cat. J/ApJS/162/227) using hfs/IS from
Roederer et al. (2008ApJ...675..723R 2008ApJ...675..723R) when available
30 = Lawler et al. (2001ApJ...556..452L 2001ApJ...556..452L), using hfs/IS from
Ivans et al. (2006, Cat. J/ApJ/645/613)
31 = Den Hartog et al. (2006 , Cat. J/ApJS/167/292)
32 = Roederer et al. (2012ApJS..203...27R 2012ApJS..203...27R)
33 = Lawler et al. (2001ApJS..137..351L 2001ApJS..137..351L), using hfs from Lawler, Wyart, &
Blaise (2001ApJS..137..351L 2001ApJS..137..351L) when available
34 = Wickliffe, Lawler, & Nave (2000, J. Quant. Spectrosc. Rad. Trans.,
66, 363)
35 = Lawler, Sneden, & Cowan (2004ApJ...604..850L 2004ApJ...604..850L) for both log gf value
and hfs
36 = Lawler et al. (2008ApJS..178...71L 2008ApJS..178...71L)
37 = Wickliffe & Lawler (1997, J., Opt., Soc., Am., B Optical Phys., 14, 737)
38 = Sneden et al. (2009, Cat. J/ApJS/182/80) for both log gf value
and hfs/IS
39 = Lawler et al. (2007, Cat. J/ApJS/169/120)
40 = Ivarsson et al. (2003A&A...409.1141I 2003A&A...409.1141I), using hfs/IS from Cowan et al.
(2005ApJ...627..238C 2005ApJ...627..238C), see note on log gf values there
41 = Biemont et al. (2000MNRAS.312..116B 2000MNRAS.312..116B), using hfs/IS from
Roederer et al. (2012, Cat. J/ApJ/750/76)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 31-Jul-2015