2020A&A...642A.176T

Query : 2020A&A...642A.176T

2020A&A...642A.176T - Astronomy and Astrophysics, volume 642A, 176-176 (2020/10-1)

The chemical evolution of the dwarf spheroidal galaxy Sextans.

THELER R., JABLONKA P., LUCCHESI R., LARDO C., NORTH P., IRWIN M., BATTAGLIA G., HILL V., TOLSTOY E., VENN K., HELMI A., KAUFER A., PRIMAS F. and SHETRONE M.

Abstract (from CDS):

We present our analysis of the FLAMES dataset targeting the central 25' region of the Sextans dwarf spheroidal galaxy (dSph). This dataset is the third major part of the high-resolution spectroscopic section of the ESO large program 171.B-0588(A) obtained by the Dwarf galaxy Abundances and Radial-velocities Team. Our sample is composed of red giant branch stars down to V∼20.5mag, the level of the horizontal branch in Sextans, and allows users to address questions related to both stellar nucleosynthesis and galaxy evolution. We provide metallicities for 81 stars, which cover the wide [Fe/H]=-3.2 to -1.5dex range. The abundances of ten other elements are derived: Mg, Ca, Ti, Sc, Cr, Mn, Co, Ni, Ba, and Eu. Despite its small mass, Sextans is a chemically evolved system, showing evidence of a contribution from core-collapse and Type Ia supernovae as well as low-metallicity asymptotic giant branch stars (AGBs). This new FLAMES sample offers a sufficiently large number of stars with chemical abundances derived with high accuracy to firmly establish the existence of a plateau in [α/Fe] at ∼0.4dex followed by a decrease above [Fe/H]~-2dex. These features reveal a close similarity with the Fornax and Sculptor dSphs despite their very different masses and star formation histories, suggesting that these three galaxies had very similar star formation efficiencies in their early formation phases, probably driven by the early accretion of smaller galactic fragments, until the UV-background heating impacted them in different ways. The parallel between the Sculptor and Sextans dSph is also striking when considering Ba and Eu. The same chemical trends can be seen in the metallicity region common to both galaxies, implying similar fractions of SNeIa and low-metallicity AGBs. Finally, as to the iron-peak elements, the decline of [Co/Fe] and [Ni/Fe] above [Fe/H]~-2 implies that the production yields of Ni and Co in SNeIa are lower than that of Fe. The decrease in [Ni/Fe] favours models of SNeIa based on the explosion of double-degenerate sub-Chandrasekhar mass white dwarfs.

Abstract Copyright: © ESO 2020

Journal keyword(s): stars: abundances - galaxies: dwarf - galaxies: evolution

VizieR on-line data: <Available at CDS (J/A+A/642/A176): table2.dat=table6.dat table9.dat-table13.dat>

Nomenclature: Table 2: [TJL2020] SNN-NNN N=112 among (Nos S05-5 to S05-168, S07-16 to S07-115, S08-3 to S08-341, S11-97 to S11-141).

Simbad objects: 118

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Number of rows : 118
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1359 4
2 NAME Fornax Dwarf Spheroidal G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1743 1
3 NAME Carina dSph G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1125 0
4 [LPP2003] 850 * 10 12 08.90 -01 35 46.7   20.92 19.99   19.10 ~ 2 0
5 [LPP2003] 494 * 10 12 12.00 -01 36 02.4   20.06 19.07   18.07 ~ 2 0
6 [LPP2003] 828 * 10 12 14.1041950488 -01 33 38.084484780   20.87 19.95   18.99 ~ 4 0
7 [LPP2003] 687 * 10 12 18.4034113080 -01 40 22.397942280   20.56 19.68   18.7 ~ 4 0
8 [LPP2003] 635 * 10 12 20.70 -01 37 39.3   20.41 19.55   18.66 ~ 2 0
9 [LPP2003] 805 * 10 12 21.2260389408 -01 44 53.017692828   20.86 19.91   18.99 ~ 4 0
10 [TJL2020] S08-337 * 10 12 22.8269397888 -01 39 22.133773728     20.17   19.11 ~ 3 0
11 [TJL2020] S08-327 * 10 12 23.0953303056 -01 37 46.830062172     20.05   18.98 ~ 3 0
12 2MASS J10122420-0144599 * 10 12 24.1969146408 -01 45 00.161750700   18.90 18.07   17.22 ~ 3 0
13 [LPP2003] 565 * 10 12 25.20 -01 33 52.9   20.30 19.39   18.38 ~ 2 0
14 [LPP2003] 540 * 10 12 25.9401653880 -01 32 38.993266212   20.22 19.25   18.23 ~ 4 0
15 [KGS2010] Sex 1023 RG* 10 12 25.9806309504 -01 47 33.160702740     20.228   19.340 ~ 3 0
16 [LPP2003] 683 * 10 12 26.7904240392 -01 45 05.191108164   20.74 19.68   18.58 ~ 4 0
17 [BTH2011] 31 * 10 12 26.9388737760 -01 44 31.822765836   20.03 19.198   18.240 ~ 7 0
18 2MASS J10122701-0130214 RG* 10 12 27.0291708192 -01 30 21.283373304     18.37   17.38 ~ 7 0
19 2MASS J10122791-0148052 RG* 10 12 27.9099612768 -01 48 05.216492628   19.18 18.18   17.12 ~ 8 0
20 [LPP2003] 596 * 10 12 29.9415234768 -01 34 31.891508688   20.31 19.41   18.42 ~ 4 0
21 [LPP2003] 742 * 10 12 30.7088418192 -01 42 07.564784868   20.72 19.8   18.83 ~ 4 0
22 [LPP2003] 768 * 10 12 31.1405820600 -01 32 53.820884688   20.75 19.84   18.87 ~ 4 0
23 [TJL2020] S08-332 * 10 12 31.8125901600 -01 32 49.708323060     20.18   19.23 ~ 3 0
24 [TJL2020] S08-111 * 10 12 32.10 -01 46 00.0     20.22   19.36 ~ 1 0
25 [LPP2003] 757 * 10 12 32.6780827296 -01 32 08.939365692   20.72 19.82   18.92 ~ 4 0
26 [TJL2020] S08-331 * 10 12 33.8784174768 -01 31 59.128433112     20.14   19.2 ~ 3 0
27 [LPP2003] 496 * 10 12 35.1282944928 -01 39 40.385806092   19.95 19.11   18.18 ~ 4 0
28 2MASS J10123587-0141152 RG* 10 12 35.9049904392 -01 41 15.263617920   19.82 18.628   17.500 ~ 9 0
29 2MASS J10123736-0149044 RG* 10 12 37.3711252416 -01 49 04.444424364   18.85 17.478   16.200 ~ 9 0
30 [TJL2020] S08-225 * 10 12 37.3833426792 -01 26 43.436260320     20.15   19.22 ~ 3 0
31 [LPP2003] 744 * 10 12 37.7105517024 -01 44 15.017151840   20.62 19.81   18.83 ~ 4 0
32 [LPP2003] 632 * 10 12 37.9072705584 -01 28 23.202158844   20.41 19.53   18.56 ~ 4 0
33 [BTH2011] 30 RG* 10 12 38.8558768200 -01 41 45.030346800   20.08 19.168   18.180 ~ 8 0
34 2MASS J10123902-0129589 RG* 10 12 39.0350141784 -01 29 59.016235236   19.12 17.87   16.64 ~ 6 0
35 [BTH2011] 1 RG* 10 12 40.2711164448 -01 29 07.720174932   20.20 19.22   18.2 ~ 6 0
36 [LPP2003] 793 * 10 12 40.6490731056 -01 35 47.715545544   21.13 19.89   18.87 ~ 4 0
37 [KGS2010] Sex 545 RG* 10 12 40.9087264752 -01 32 01.288983372   20.18 19.248   18.290 ~ 7 0
38 2MASS J10124160-0132514 RG* 10 12 41.6038368672 -01 32 51.623897424   18.95 17.59   16.32 ~ 7 0
39 2MASS J10124182-0145273 RG* 10 12 41.8331466864 -01 45 27.354716244   18.80 17.298   15.920 ~ 12 0
40 [LPP2003] 474 * 10 12 42.8298774288 -01 30 08.399197044   19.84 18.99   18.01 ~ 4 0
41 [KGS2010] Sex 1125 RG* 10 12 43.0293502536 -01 33 10.995045624     20.308   19.390 ~ 3 0
42 [KGS2010] Sex 740 RG* 10 12 43.1143227192 -01 40 15.012433020   20.68 19.768   18.790 ~ 7 0
43 [KGS2010] Sex 539 * 10 12 44.3116882656 -01 33 48.392655552   20.08 19.218   18.290 ~ 4 0
44 2MASS J10124468-0142488 * 10 12 44.7027672216 -01 42 48.988263708   20.56 18.93   17.76 ~ 5 0
45 [BTH2011] 28 RG* 10 12 45.4734935352 -01 47 56.051424420   19.63 18.858   17.980 ~ 8 0
46 [BTH2011] 2 RG* 10 12 47.9875454376 -01 29 38.806257228   19.84 18.98   18.04 ~ 6 0
47 2MASS J10124929-0142183 RG* 10 12 49.3219217592 -01 42 18.043125516   19.82 18.7   17.65 ~ 7 0
48 [LPP2003] 836 * 10 12 50.5451496264 -01 33 33.059581164   20.86 19.96   18.99 ~ 4 0
49 [LPP2003] 799 * 10 12 50.6036901168 -01 34 56.887239324   20.81 19.9   18.91 ~ 4 0
50 [BTH2011] 81 * 10 12 51.9451108752 -01 30 00.914208336   20.55 19.66   18.7 ~ 5 0
51 [LPP2003] 721 * 10 12 53.7242862744 -01 45 03.094462872   20.64 19.76   18.81 ~ 4 0
52 2MASS J10125392-0145273 RG* 10 12 53.8910544432 -01 45 27.219585420   19.95 18.96   17.94 ~ 6 0
53 [TJL2020] S08-336 * 10 12 54.5597631144 -01 35 49.231848084     20.23   19.3 ~ 3 0
54 [BTH2011] 25 RG* 10 12 56.3141783832 -01 39 21.178640664   20.09 19.148   18.160 ~ 7 0
55 [LPP2003] 756 * 10 12 58.8342853896 -01 28 25.833074412   20.83 19.82   18.82 ~ 4 0
56 [KGS2010] Sex 885 RG* 10 12 59.1701000256 -01 34 42.696466140     20.008   19.060 ~ 6 0
57 [BTH2011] 80 RG* 10 12 59.4861809688 -01 28 03.489387384   20.43 19.55   18.62 ~ 6 0
58 [LPP2003] 697 * 10 12 59.50 -01 33 45.2   20.50 19.71   18.81 ~ 2 0
59 [TJL2020] S08-222 * 10 13 00.6552984384 -01 30 35.655272424     20.15   19.17 ~ 3 0
60 [KGS2010] Sex 990 RG* 10 13 00.7850311200 -01 41 05.947811268     20.198   19.290 ~ 3 0
61 [KGS2010] Sex 760 * 10 13 01.4263934520 -01 36 24.266914812   20.60 19.788   18.840 ~ 4 0
62 [KGS2010] Sex 741 * 10 13 01.8709024248 -01 35 24.355515120   20.68 19.768   18.800 ~ 6 0
63 [LPP2003] 660 * 10 13 02.0838790152 -01 36 58.786087212   20.18 19.61   18.7 ~ 4 0
64 [LPP2003] 761 * 10 13 02.10 -01 46 08.9   20.80 19.88   18.85 ~ 2 0
65 NAME Sextans dSph G 10 13 02.9 -01 36 53   12 10.4     ~ 854 0
66 2MASS J10130307-0142141 * 10 13 03.0940052904 -01 42 14.144012748   19.79 18.45   17.39 ~ 5 0
67 [TJL2020] S08-323 * 10 13 03.3253622448 -01 37 22.733843556     20.04   19.05 ~ 3 0
68 [LPP2003] 794 * 10 13 04.5151416744 -01 26 10.790752020   20.72 19.89   19.03 ~ 4 0
69 [BTH2011] 22 * 10 13 04.8913380552 -01 45 10.969846488   20.50 19.15   18.08 ~ 5 0
70 [KHI2013] II-11 * 10 13 05.6532272856 -01 31 28.033629096     19.49   18.45 ~ 4 0
71 2MASS J10130589-0144517 RG* 10 13 05.8993253136 -01 44 51.654911712   19.51 18.45   17.31 ~ 7 0
72 [TJL2020] S08-317 * 10 13 06.2866768176 -01 33 10.545234948     20   19.07 ~ 3 0
73 [KGS2010] Sex 772 * 10 13 06.6729627384 -01 34 19.610213268   20.65 19.808   18.860 ~ 6 0
74 [BTH2011] 18 RG* 10 13 07.5695635872 -01 41 13.081583616   20.15 19.308   18.370 ~ 8 0
75 [KGS2010] Sex 825 RG* 10 13 08.2258418376 -01 35 53.688346476   20.84 19.918   19.020 ~ 7 0
76 [KGS2010] Sex 564 * 10 13 08.9100144312 -01 36 04.784974992   20.09 19.298   18.360 ~ 4 0
77 [LPP2003] 796 * 10 13 09.6756612960 -01 37 33.178359684   20.70 19.9   18.94 ~ 4 0
78 [BTH2011] 4 RG* 10 13 09.9373912872 -01 29 35.032368228   20.24 19.288   18.290 ~ 8 0
79 2MASS J10131018-0142074 RG* 10 13 10.2008015520 -01 42 07.239440700   19.81 18.768   17.690 ~ 8 0
80 2MASS J10131023-0140509 RG* 10 13 10.2265448592 -01 40 51.137192640   19.46 18.318   17.170 ~ 8 0
81 [TJL2020] S08-322 * 10 13 11.20 -01 42 36.2     20.02   19.13 ~ 1 0
82 [KGS2010] Sex 690 RG* 10 13 11.2328127288 -01 35 01.975623936   20.53 19.658   18.690 ~ 7 0
83 [LPP2003] 736 * 10 13 11.9546393016 -01 29 46.761938484   20.65 19.8   18.82 ~ 4 0
84 [BTH2011] 82 RG* 10 13 12.4697020536 -01 29 17.275232112   20.63 19.71   18.68 ~ 6 0
85 [KGS2010] Sex 1063 RG* 10 13 14.1043644624 -01 33 48.685603212     20.268   19.350 ~ 3 0
86 [BTH2011] 11 RG* 10 13 16.7277362880 -01 39 56.768810004   20.07 19.14   18.08 ~ 6 0
87 [BTH2011] 6 RG* 10 13 17.1445836240 -01 26 38.110918668   20.01 18.94   17.92 ~ 7 0
88 [BTH2011] 8 RG* 10 13 18.2774296920 -01 35 15.873530532   20.07 19.208   18.210 ~ 8 0
89 [BTH2011] 5 * 10 13 18.9637984584 -01 26 58.373723796   20.30 19.38   18.38 ~ 5 0
90 [LPP2003] 848 * 10 13 19.7150360232 -01 33 26.083433412   20.85 19.98   19.04 ~ 4 0
91 [LPP2003] 575 * 10 13 20.80 -01 35 57.5   20.29 19.30   18.31 ~ 2 0
92 [TJL2020] S05-123 * 10 13 21.1370250888 -01 33 27.833062212     20.13   19.21 ~ 3 0
93 [LPP2003] 738 * 10 13 21.70 -01 47 44.3   20.65 19.79   18.93 ~ 2 0
94 [LPP2003] 851 * 10 13 22.70 -01 33 41.6   20.80 19.95   19.09 ~ 2 0
95 [BTH2011] 7 RG* 10 13 25.9861216344 -01 36 11.101439412   19.92 18.938   17.900 ~ 9 0
96 [BTH2011] 21 * 10 13 26.0682913992 -01 45 25.122850596   20.58 19.30   18.39 ~ 4 0
97 [BTH2011] 76 RG* 10 13 26.2745991096 -01 31 50.316249144   20.63 19.82   18.90 ~ 5 0
98 [KGS2010] Sex 792 RG* 10 13 26.4196694520 -01 36 36.299520648   20.73 19.848   18.900 ~ 7 0
99 [LPP2003] 614 * 10 13 27.10 -01 47 27.4   20.34 19.44   18.56 ~ 2 0
100 [KGS2010] Sex 1084 RG* 10 13 27.3178116696 -01 30 56.789194464     20.288   19.390 ~ 6 0
101 2MASS J10132736-0134051 RG* 10 13 27.3738415080 -01 34 04.955737368   19.13 17.94   16.86 ~ 7 0
102 [BTH2011] 20 * 10 13 28.5714125616 -01 45 10.648216440     19.37   18.44 ~ 4 0
103 [BTH2011] 77 * 10 13 33.0637075440 -01 30 53.909848008   20.80 19.93   19.07 ~ 4 0
104 [LPP2003] 758 * 10 13 34.9923891960 -01 29 50.014323132   20.67 19.82   18.84 ~ 4 0
105 [KGS2010] Sex 642 RG* 10 13 37.2636369264 -01 32 04.555173732   20.35 19.518   18.600 ~ 7 0
106 [BTH2011] 24 RG* 10 13 37.4143069872 -01 44 32.209123560   19.70 18.78   17.78 ~ 7 0
107 [LPP2003] 537 * 10 13 37.6509318528 -01 42 57.726597492   20.10 19.24   18.29 ~ 4 0
108 [KGS2010] Sex 858 RG* 10 13 37.8478833648 -01 38 15.677887560     19.968   19.080 ~ 6 0
109 2MASS J10133878-0140463 RG* 10 13 38.6684554656 -01 40 45.923989296   19.77 18.83   17.77 ~ 7 0
110 [LPP2003] 521 * 10 13 38.6965352904 -01 39 13.176493848   20.02 19.2   18.23 ~ 4 0
111 [BTH2011] 13 RG* 10 13 40.2044617752 -01 38 48.604671024   19.86 18.95   17.91 ~ 6 0
112 2MASS J10134025-0133399 * 10 13 40.2700900512 -01 33 39.807433584   19.10 18.008   16.810 ~ 9 0
113 [LPP2003] 813 * 10 13 40.9175970720 -01 43 53.027258016   20.62 19.92   19.04 ~ 4 0
114 [BTH2011] 17 RG* 10 13 41.4478935048 -01 35 38.999328900   20.09 19.198   18.200 ~ 8 0
115 [TJL2020] S07-115 * 10 13 43.0219928328 -01 37 13.706431500     20.16   19.28 ~ 3 0
116 [BTH2011] 16 RG* 10 13 44.9939343480 -01 36 30.920569056   19.91 19.108   18.170 ~ 8 0
117 NAME UMi Galaxy G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1360 0
118 NAME Dra dSph G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1331 1

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