2018A&A...620A.187F

Query : 2018A&A...620A.187F

2018A&A...620A.187F - Astronomy and Astrophysics, volume 620A187-187 (2018/12-1)

TOPoS. V. Abundance ratios in a sample of very metal-poor turn-off stars.

FRANCOIS P., CAFFAU E., BONIFACIO P., SPITE M., SPITE F., CAYREL R., CHRISTLIEB N., GALLAGHER A.J., KLESSEN R., KOCH A., LUDWIG H.-G., MONACO L., PLEZ B., STEFFEN M. and ZAGGIA S.

Abstract (from CDS):


Context. Extremely metal-poor stars are keys to understand the early evolution of our Galaxy. The ESO large programme TOPoS has been tailored to analyse a new set of metal-poor turn-off stars, whereas most of the previously known extremely metal-poor stars are giant stars.
Aims. Sixty five turn-off stars (preselected from SDSS spectra) have been observed with the X-shooter spectrograph at the ESO VLT Unit Telescope 2, to derive accurate and detailed abundances of magnesium, silicon, calcium, iron, strontium and barium.
Methods. We analysed medium-resolution spectra (R~=10000) obtained with the ESO X-shooter spectrograph and computed the abundances of several α and neutron-capture elements using standard one-dimensional local thermodynamic equilibrium (1D LTE) model atmospheres.
Results. Our results confirms the super-solar [Mg/Fe] and [Ca/Fe] ratios in metal-poor turn-off stars as observed in metal-poor giant stars. We found a significant spread of the [α/Fe] ratios with several stars showing subsolar [Ca/Fe] ratios. We could measure the abundance of strontium in 12 stars of the sample, leading to abundance ratios [Sr/Fe] around the Solar value. We detected barium in two stars of the sample. One of the stars (SDSS J114424-004658) shows both very high [Ba/Fe] and [Sr/Fe] abundance ratios (>1dex).

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: abundances - Galaxy: abundances

VizieR on-line data: <Available at CDS (J/A+A/620/A187): tablea1.dat tablea2.dat tablea3.dat>

Simbad objects: 65

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Number of rows : 65
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 SDSS J000411.61-055027.7 Pe* 00 04 11.6079946656 -05 50 27.668758560           A0 2 0
2 2MASS J00255862-1015097 Pe* 00 25 58.6036644960 -10 15 09.469945152           A0 3 0
3 SDSS J003507.69-005037.8 Pe* 00 35 07.6939456584 -00 50 37.847330808           F2III 3 0
4 SDSS J003954.65-001856.5 Pe* 00 39 54.6513719640 -00 18 56.549181996           A0 2 0
5 2MASS J01203263-1001064 Pe* 01 20 32.6321129400 -10 01 06.539188908           F5 7 0
6 SDSS J012125.10-030943.6 Pe* 01 21 25.1014808208 -03 09 43.598479176           A2II 2 0
7 SDSS J012442.10-002806.7 Pe* 01 24 42.1069973904 -00 28 06.831359688           sdA 3 0
8 SDSS J014036.21+234458.1 Pe* 01 40 36.2207485632 +23 44 58.206182748   15.6       CEMP-no 40 0
9 SDSS J014721.85+021819.8 Pe* 01 47 21.8529189072 +02 18 19.958930568           A5III 3 0
10 SDSS J014828.99+150221.5 Pe* 01 48 28.9922454240 +15 02 21.528867048           A0 3 0
11 2MASS J02123845+0137580 Pe* 02 12 38.4778861392 +01 37 58.171033344           CEMP-no 12 0
12 SDSS J021554.33+063901.4 Pe* 02 15 54.3263413368 +06 39 01.381184424           ~ 2 0
13 SDSS J030549.63+050826.8 Pe* 03 05 49.6319549640 +05 08 26.818507320           A0 1 0
14 SDSS J031348.14+011456.4 Pe* 03 13 48.1467528456 +01 14 56.458496688           A0 2 0
15 SDSS J035925.55-063416.0 Pe* 03 59 25.5581909688 -06 34 16.091101380           A0III 3 0
16 SDSS J040114.71-051259.0 Pe* 04 01 14.7138704808 -05 12 59.009119560           G0III 5 0
17 2MASS J07474861+2645434 Pe* 07 47 48.6192148272 +26 45 43.559209548           A0 6 0
18 SDSS J075338.62+190855.6 Pe* 07 53 38.6219516016 +19 08 55.600415376           A0 2 0
19 SDSS J080336.58+053430.6 Pe* 08 03 36.5786900784 +05 34 30.691797132           A0 3 0
20 SDSS J082506.65+192753.4 Pe* 08 25 06.6510066336 +19 27 53.593913304           A0 1 0
21 Cl* NGC 2682 FBC 5324 Pe* 08 52 32.9071999392 +11 23 31.170338304           ~ 3 0
22 SDSS J090533.37-020843.8 Pe* 09 05 33.3770944560 -02 08 43.792649952           A0II 3 0
23 SDSS J091913.14+232738.4 Pe* 09 19 13.1450233848 +23 27 38.467753740           F5 3 0
24 SDSS J103402.71+070116.6 Pe* 10 34 02.7117793776 +07 01 16.671733572           A0IV 8 0
25 SDSS J104531.22-010741.8 Pe* 10 45 31.2203029200 -01 07 41.864352744           A0 1 0
26 2MASS J10500235+2421098 Pe* 10 50 02.3409816312 +24 21 09.767950740           F5 5 0
27 SDSS J105231.68-004008.5 Pe* 10 52 31.6917029376 -00 40 08.520210120           A0 1 0
28 SDSS J112031.80-124638.9 Pe* 11 20 31.8170338824 -12 46 38.900959248           A0 2 0
29 SDSS J112211.81-114809.2 Pe* 11 22 11.8154362584 -11 48 09.158991444           A0 2 0
30 SDSS J112750.90-072711.5 Pe* 11 27 50.9079377952 -07 27 11.473191900           A0 2 0
31 SDSS J114424.63-004658.6 Pe* 11 44 24.6384864336 -00 46 58.628202744           sdA 3 0
32 SDSS J120441.38+120111.5 Pe* 12 04 41.3884587048 +12 01 11.514049212           A0 17 0
33 2MASS J12305523+0005467 Pe* 12 30 55.2495483528 +00 05 46.893806376           sdA 9 0
34 SDSS J123404.57+134411.4 Pe* 12 34 04.5775389960 +13 44 11.402652012           A0 3 0
35 SDSS J124121.48-021228.6 Pe* 12 41 21.4841755680 -02 12 28.542619620           A0 2 0
36 SDSS J124304.19-081230.6 Pe* 12 43 04.2110094888 -08 12 30.585348432           ~ 4 0
37 SDSS J124719.46-034152.4 Pe* 12 47 19.4672289864 -03 41 52.504507176           A0 8 0
38 SDSS J131249.61+001315.6 Pe* 13 12 49.6121317872 +00 13 15.624828876           A0 2 0
39 SDSS J131456.86+113753.4 Pe* 13 14 56.8548613728 +11 37 53.393573748           A0 2 0
40 SDSS J131948.62+233436.5 Pe* 13 19 48.6244997208 +23 34 36.546797928           A0 1 0
41 SDSS J132112.17+010256.0 Pe* 13 21 12.1834773936 +01 02 56.149394712           A0 1 0
42 SDSS J132508.60+222424.7 Pe* 13 25 08.6021450856 +22 24 24.631246800           sdA 3 0
43 SDSS J135046.74+134651.1 Pe* 13 50 46.7504473944 +13 46 51.165697152           A0 3 0
44 SDSS J135331.01-032930.2 Pe* 13 53 31.0183504440 -03 29 30.125467248           O9IV 4 0
45 SDSS J140007.59+191236.3 Pe* 14 00 07.5959352624 +19 12 36.360525168           A0 1 0
46 SDSS J141249.08+013206.7 Pe* 14 12 49.0795398960 +01 32 06.680523624           A0III 4 0
47 SDSS J150702.02+005152.6 Pe* 15 07 02.0210528784 +00 51 52.610505084           A0 5 0
48 SDSS J153747.78+281404.6 Pe* 15 37 47.7799320288 +28 14 04.509118932           F0V 3 0
49 SDSS J154746.50+242953.1 Pe* 15 47 46.5007207704 +24 29 53.088597708           F0III 4 0
50 SDSS J155159.34+253900.6 Pe* 15 51 59.3421474624 +25 39 00.612628164           A0 2 0
51 SDSS J155751.76+190306.2 Pe* 15 57 51.7671938952 +19 03 06.291516312           A2II 2 0
52 SDSS J172552.20+274116.6 Pe* 17 25 52.2077804376 +27 41 16.666002276           A0 2 0
53 SDSS J173358.01+274952.3 Pe* 17 33 58.0161876504 +27 49 52.359944376           ~ 1 0
54 2MASS J20051348-1045030 Pe* 20 05 13.4796995904 -10 45 03.235342644           sdA 9 0
55 SDSS J214633.18-003910.2 Pe* 21 46 33.1836792360 -00 39 10.237184856           A2II 4 0
56 SDSS J215023.51+031928.2 Pe* 21 50 23.5131030000 +03 19 28.234655904           A2II 2 0
57 SDSS J215805.91+091417.0 Pe* 21 58 05.9148694128 +09 14 17.242913688           sdA 4 0
58 SDSS J220121.77+010055.6 Pe* 22 01 21.7671388848 +01 00 55.567894788           A0 3 0
59 SDSS J220728.08+055658.7 Pe* 22 07 28.0907389800 +05 56 58.735325472           A0 2 0
60 SDSS J222130.22+000617.0 Pe* 22 21 30.2319992016 +00 06 17.124960420           A0 3 0
61 SDSS J225429.61+062728.2 Pe* 22 54 29.6149645896 +06 27 28.336276080           F0V 2 0
62 SDSS J230243.33-094346.0 Pe* 23 02 43.3364055840 -09 43 46.041358656           B6 2 0
63 SDSS J231031.86+031847.6 Pe* 23 10 31.8458791320 +03 18 47.719183968           A2II 4 0
64 SDSS J231755.56+004537.7 Pe* 23 17 55.5657379800 +00 45 37.824222132           ~ 2 0
65 SDSS J235210.23+140140.2 Pe* 23 52 10.2362091576 +14 01 40.254491100           A0 2 0

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