J/ApJ/612/447 Draco 119 and HD 88609 equivalent widths (Fulbright+, 2004)
Draco 119: a remarkable heavy-element-deficient giant.
Fulbright J.P., Rich R.M., Castro S.
<Astrophys. J., 612, 447-453 (2004)>
=2004ApJ...612..447F 2004ApJ...612..447F
ADC_Keywords: Equivalent widths ; Stars, metal-deficient
Keywords: galaxies: individual (Draco) -
nuclear reactions, nucleosynthesis, abundances - stars: abundances
Abstract:
We report the abundance analysis of new high signal-to-noise ratio
(S/N) spectra of the most metal-poor ([Fe/H]=-2.95) star currently
known to be a member of a dwarf galaxy, the Draco dSph red giant D119.
No absorption lines for elements heavier than Ni are detected in two
Keck HIRES spectra covering the 3850-6655Å wavelength range, a
phenomenon not previously noted in any other metal-poor star. We
present upper limits for several heavy-element abundances. The most
stringent limits, based on the nondetection of SrII and BaII lines,
indicate that the total s- and r-process enrichment of D119 is at
least 100times smaller than Galactic stars of similar metallicity. The
light-element abundances are consistent with the star having formed
out of material enriched primarily by massive Type II supernovae
(M>20-25M☉). If this is the case, we are forced to conclude that
massive, metal-poor Type II supernovae did not contribute to the
r-process in the proto-Draco environment. We compare the abundance
pattern observed in D119 to current predictions of prompt enrichment
and pair-instability supernovae and find that the model predictions
fail by an order of magnitude or more for many elements.
Description:
The data are obtained using two settings of the HIRES spectrograph
on the Keck I telescope, on 2000 July 6 and 2001 June 29.
Objects:
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RA (2000) DE Designation(s)
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17 20 16.1 +57 52 56 Draco 119 = [BS61] 119
10 14 29.0 +53 33 39 HD 88609
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 180 Line list
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Wavelength
9- 13 A5 --- Ion Ion (1)
17- 20 F4.2 eV EP Excitation potential
25- 30 F6.3 --- log(gf) ? Log of oscillator strength
32 A1 --- f_log(gf) [b] Flag on log(gf) (2)
34 A1 --- l_EW1 Limit on EW1
35- 37 I3 0.1pm EW1 ? Equivalent width for Draco 119
39 A1 --- n_EW1 [abc] Note on EW1 (3)
43- 45 I3 0.1pm EW2 ? Equivalent width for HD88609
47 A1 --- n_EW2 [abc] Note on EW2 (3)
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Note (1): CH line analysis assumed a dissociation energy of 3.47eV.
Note (2): 'b' indicates lines treated as blends of many hyperfine components.
Hyperfine data were taken from Johnson (2002ApJS..139..219J 2002ApJS..139..219J),
McWilliam (1998AJ....115.1640M 1998AJ....115.1640M), and McWilliam et al. (1995AJ....109.2757M 1995AJ....109.2757M).
Note (3): Values for EW1 and EW2 followed by the same note letter
should be taken as blended together.
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History:
From electronic version of the journal
(End) Marianne Brouty [CDS] 21-Mar-2005