J/A+A/626/A15 Sculptor Red Giant Branch stars abundances (Hill+, 2019)
VLT/FLAMES high-resolution chemical abundances in Sculptor:
a textbook dwarf spheroidal galaxy.
Hill V., Skuladottir A., Tolstoy E., Venn K.A., Shetrone M.D., Jablonka P.,
Primas F., Battaglia G., de Boer T.J.L, Francois P., Helmi A., Kaufer A.,
Letarte B., Starkenburg E., Spite M.
<Astron. Astrophys. 626, A15 (2019)>
=2019A&A...626A..15H 2019A&A...626A..15H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, giant ; Abundances
Keywords: stars: abundances - galaxies: abundances - galaxies: evolution -
galaxies: dwarf - galaxies: individual: Sculptor - Local Group
Abstract:
We present detailed chemical abundances for 99 Red Giant Branch stars
in the centre of the Sculptor dwarf spheroidal galaxy, which have been
obtained from high-resolution VLT/FLAMES spectroscopy. The abundances
of Li, Na, alpha-elements (O, Mg, Si, Ca Ti), iron-peak elements (Sc,
Cr, Fe, Co, Ni, Zn), r- and s-process elements (Ba, La, Nd, Eu) were
all derived using stellar atmosphere models and semi-automated
analysis techniques. The iron abundances, covering the range
-2.3<[Fe/H]←0.9, populate the whole metallicity distribution of the
galaxy with the exception of the very low metallicity tail. There is a
marked decrease in [α/Fe] over our sample, from the Galactic
halo plateau value at low [Fe/H] and then, after a 'knee', a decrease
to sub-solar [alpha/Fe] at high [Fe/H]. This is consistent with
products of core-collapse supernovae dominating at early times,
followed by the onset of supernovae type Ia as early as ∼12Gyr ago.
The products from low-mass AGB stars, as traced by the s-process, also
participate in the chemical evolution of Sculptor with a timescale
comparable to that of supernovae type Ia. However, the r-process is
consistent with having no time delay relative to core-collapse
supernovae, at least at the later stages of the chemical evolution in
Sculptor. Using the simple and well-behaved chemical evolution of
Sculptor, we further derive empirical constraints on the relative
importance of massive stars and supernovae type Ia to the
nucleosynthesis of individual iron-peak and alpha-elements. The most
important contribution of supernovae typeIa is to the iron-peak
elements: Fe, Cr and Mn; but there is also a modest but non-negligible
contribution to both the heavier alpha-elements: S, Ca and Ti, and
some of the iron-peak elements: Sc and Co. We see only very small or
no contribution to O, Mg, Ni and Zn from supernovae type Ia in
Sculptor. The observed chemical abundances in Sculptor show no
evidence of a significantly different initial mass function, compared
to that of the Milky Way. With the exception of neutron-capture
elements at low [Fe/H], the scatter around mean trends in Sculptor for
[Fe/H]>-2.3 is extremely low, and compatible with observational
errors. Combined with the small scatter in the age-elemental
abundances relation, this calls for an efficient mixing of metals in
the gas in the centre of Sculptor since ∼12Gyr ago.
Description:
List of the 99 target stars and their magnitudes, atmospheric
parameters, ages, chemical abundances and measured Equivalent widths,
along with the line list.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablec1.dat 149 129 Target stars, astrometry, magnitudes, velocities
tablec2.dat 38 186 Line list
tablec3.dat 81 99 Stellar atmospheric parameters and ages
tablec4.dat 36 10163 Equivalent widths for 99 stars
tablec5.dat 204 99 Chemical abundances
--------------------------------------------------------------------------------
See also:
J/A+A/574/A129 : The First CEMP star in the Sculptor dSph (Skuladottir+, 2015)
J/A+A/580/A129 : Sulphur in the Sculptor dSph (Skuladottir+, 2015)
J/A+A/606/A71 : dSph RGB abundance and velocities (Skuladottir+, 2017)
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Star Star ID
9 I1 h RAh Right Ascension (J2000, Epoch 1989.0)
11- 12 I2 min RAm Right Ascension (J2000, Epoch 1989.0)
14- 18 F5.2 s RAs Right Ascension (J2000, Epoch 1989.0)
20 A1 --- DE- Declination sign (J2000, Epoch 1989.0)
21- 22 I2 deg DEd Declination (J2000, Epoch 1989.0)
24- 25 I2 arcmin DEm Declination (J2000, Epoch 1989.0)
27- 31 F5.2 arcsec DEs Declination (J2000, Epoch 1989.0)
33- 38 F6.3 mag Vmag V magnitude
40- 45 F6.3 mag Imag I magnitude
47- 52 F6.3 mag Jmag ?=- J magnitude
54- 59 F6.3 mag Kmag ?=- K magnitude
61- 66 F6.2 km/s RV ?=- Radial velocity
68- 71 F4.2 km/s e_RV ?=- Error on radial velocity
73- 74 I2 1/pix S/N ?=- Signal-to-noise ratio
76- 94 I19 --- GaiaID Gaia ID
96-101 F6.3 mas/yr pmRA Proper motion along RA
103-107 F5.3 mas/yr e_pmRA Error on proper motion along RA
109-115 F7.3 mas/yr pmDE Proper motion along DE
117-121 F5.3 mas/yr e_pmDE Error on proper motion along DE
123-149 A27 --- Com Comment (NM = not a Sculptor member)
------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- X Ion
9- 15 F7.2 0.1nm lambda Wavelength
17- 20 F4.2 eV chi Excitation potential
25- 31 F7.3 --- loggf Oscillator strength
36- 38 A3 --- Ref Reference (1)
--------------------------------------------------------------------------------
Note (1): Reference as follows:
S03 = Shetrone et al., 2003AJ....125..684S 2003AJ....125..684S
P08 = Pompeia et al., 2008, Cat. J/A+A/480/379
L10 = Letarte et al., 2010, Cat. J/A+A/523/A17
------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Star Star ID
9- 12 I4 K T(V-I) Effective temperature, from color (V-I)
14- 17 I4 K T(V-K) ?=- Effective temperature, from color (V-K)
19- 22 I4 K T(V-J) ?=- Effective temperature, from color (V-J)
24- 28 F5.2 mag BC(V) Bolometric correction (V)
30- 34 F5.2 mag Mbol Bolometric magnitude
36- 39 F4.2 --- loggp Gravity from photometry
41- 44 I4 K Teff Adopted effective temperature
46- 48 F3.1 --- logg Adopted gravity, log(g), from spectroscopy
50- 52 F3.1 km/s vt Microturbulence velocity
54- 58 F5.2 --- [FeI/H] Iron abundance (FeI)
60- 64 F5.2 --- [FeII/H] Iron abundance (FeII)
66- 70 F5.2 Gyr Agemin Minimum age
72- 76 F5.2 Gyr Agemean ?=- Mean age
78- 81 F4.2 Gyr e_Agemean ?=- Error on age
------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Star Star ID
9- 13 A5 --- X Ion
17- 23 F7.2 0.1nm lambda Wavelength
25- 29 F5.1 0.1pm EW ?=- Equivalent width
31- 34 F4.1 0.1pm e_EW ?=- Error on equivalent width
36 A1 --- Flag [*] Lines not used for abundance determination
------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Star Star ID
9- 13 F5.2 --- [Fe/H] Fe abundance
15- 18 F4.2 --- e_[Fe/H] Error on [Fe/H]
20- 24 F5.2 --- [O/Fe] ?=- O abundance
26- 29 F4.2 --- e_[O/Fe] ?=- Error on [O/Fe]
31- 35 F5.2 --- [Na/Fe] ?=- Na abundance
37- 40 F4.2 --- e_[Na/Fe] ?=- Error on [Na/Fe]
42- 46 F5.2 --- [Mg/Fe] ?=- Mg abundance
48- 51 F4.2 --- e_[Mg/Fe] ?=- Error on [Mg/Fe]
53- 57 F5.2 --- [Si/Fe] ?=- Si abundance
59- 62 F4.2 --- e_[Si/Fe] ?=- Error on [Si/Fe]
64- 68 F5.2 --- [Ca/Fe] Ca abundance
70- 73 F4.2 --- e_[Ca/Fe] Error on [Ca/Fe]
75- 79 F5.2 --- [Sc/Fe] ?=- Sc abundance
81- 84 F4.2 --- e_[Sc/Fe] ?=- Error on [Sc/Fe]
86- 90 F5.2 --- [TiI/Fe] ?=- TiI abundance
92- 95 F4.2 --- e_[TiI/Fe] ?=- Error on [TiI/Fe]
97-101 F5.2 --- [TiII/Fe] TiII abundance
103-106 F4.2 --- e_[TiII/Fe] Error on [TiII/Fe]
108-112 F5.2 --- [Cr/Fe] ?=- Cr abundance
114-117 F4.2 --- e_[Cr/Fe] ?=- Error on [Cr/Fe]
119-122 F4.2 --- [FeII/Fe] FeII abundance
124-127 F4.2 --- e_[FeII/Fe] Error on [FeII/Fe]
129-133 F5.2 --- [Co/Fe] ?=- Co abundance
135-138 F4.2 --- e_[Co/Fe] ?=- Error on [Co/Fe]
140-144 F5.2 --- [Ni/Fe] ?=- Ni abundance
146-149 F4.2 --- e_[Ni/Fe] ?=- Error on [Ni/Fe]
151-155 F5.2 --- [Zn/Fe] ?=- Zn abundance
157-160 F4.2 --- e_[Zn/Fe] ?=- Error on [Zn/Fe]
162-166 F5.2 --- [Ba/Fe] ?=- Ba abundance
168-171 F4.2 --- e_[Ba/Fe] ?=- Error on [Ba/Fe]
173-177 F5.2 --- [La/Fe] ?=- La abundance
179-182 F4.2 --- e_[La/Fe] ?=- Error on [La/Fe]
184-188 F5.2 --- [Nd/Fe] ?=- Nd abundance
190-193 F4.2 --- e_[Nd/Fe] ?=- Error on [Nd/Fe]
195-199 F5.2 --- [Eu/Fe] ?=- Eu abundance
201-204 F4.2 --- e_[Eu/Fe] ?=- Error on [Eu/Fe]
------------------------------------------------------------------------------
Acknowledgements:
Asa Skuladottir, skuladottir(at)mpia.de
Vanessa Hill, Vanessa.Hill(at)oca.eu
(End) Asa Skuladottir [MPIA, Heidelberg], Patricia Vannier [CDS] 23-Apr-2019