2019A&A...625A.104R


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.03CET02:07:32

2019A&A...625A.104R - Astronomy and Astrophysics, volume 625A, 104-104 (2019/5-1)

Testing massive star evolution, star formation history, and feedback at low metallicity. Spectroscopic analysis of OB stars in the SMC Wing.

RAMACHANDRAN V., HAMANN W.-R., OSKINOVA L.M., GALLAGHER J.S., HAINICH R., SHENAR T., SANDER A.A.C., TODT H. and FULMER L.

Abstract (from CDS):

Stars that start their lives with spectral types O and early B are the progenitors of core-collapse supernovae, long gamma-ray bursts, neutron stars, and black holes. These massive stars are the primary sources of stellar feedback in star-forming galaxies. At low metallicities, the properties of massive stars and their evolution are not yet fully explored. Here we report a spectroscopic study of 320 massive stars of spectral types O (23 stars) and B (297 stars) in the Wing of the Small Magellanic Cloud (SMC). The spectra, which we obtained with the ESO Very Large Telescope, were analyzed using state-of-the-art stellar atmosphere models, and the stellar parameters were determined. We find that the stellar winds of our sample stars are generally much weaker than theoretically expected. The stellar rotation rates show broad, tentatively bimodal distributions. The upper Hertzsprung-Russell diagram (HRD) is well populated by the stars of our sample from a specific field in the SMC Wing. A few very luminous O stars are found close to the main sequence, while all other, slightly evolved stars obey a strict luminosity limit. Considering additional massive stars in evolved stages, with published parameters and located all over the SMC, essentially confirms this picture. The comparison with single-star evolutionary tracks suggests a dichotomy in the fate of massive stars in the SMC. Only stars with an initial mass below ∼30M seem to evolve from the main sequence to the cool side of the HRD to become a red supergiant and to explode as type II-P supernova. In contrast, stars with initially more than ∼30M appear to stay always hot and might evolve quasi chemically homogeneously, finally collapsing to relatively massive black holes. However, we find no indication that chemical mixing is correlated with rapid rotation. We measured the key parameters of stellar feedback and established the links between the rates of star formation and supernovae. Our study demonstrates that in metal-poor environments stellar feedback is dominated by core-collapse supernovae in combination with winds and ionizing radiation supplied by a few of the most massive stars. We found indications of the stochastic mode of massive star formation, where the resulting stellar population is fully capable of producing large-scale structures such as the supergiant shell SMC-SGS 1 in the Wing. The low level of feedback in metal-poor stellar populations allows star formation episodes to persist over long timescales.

Abstract Copyright: © ESO 2019

Journal keyword(s): stars: evolution - stars: massive - stars: mass-loss - Magellanic Clouds - Hertzsprung-Russell and C-M diagrams - techniques: spectroscopic

VizieR on-line data: <Available at CDS (J/A+A/625/A104): tableb1.dat tableb2.dat tableb4.dat>

Nomenclature: Table B.1: SMCSGS-FS NNN (Nos 1-320).

Status at CDS : Acronym for new objects described in the dictionary of nomenclature and being created in SIMBAD. // All or part of tables of objects will be ingested in SIMBAD with priority 1.

Simbad objects: 30

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Number of rows : 30

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11211 1
2 LHA 115-N 11 EmO 00 45 02.90 -73 16 40.0   14.36       ~ 19 0
3 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9702 1
4 NGC 330 Cl* 00 56 20.59 -72 27 12.5 9.37 9.76 9.55   8.89 ~ 371 0
5 IC 1613 GiC 01 04 54.2 +02 08 00   10.42 10.01 9.77   ~ 1121 2
6 HD 6884 s*b 01 07 18.2183812921 -72 28 03.658768522   10.32 10.2     B9Ia0ek 114 0
7 DEM S 160 HII 01 23 22.4 -73 21 59           ~ 5 0
8 LHA 115-N 88 HII 01 24 08.1 -73 09 04           ~ 68 1
9 DEM S 161 HII 01 24 45.4 -73 09 34           ~ 16 0
10 DEM S 162 HII 01 24 48.9 -73 27 34           ~ 5 0
11 DEM S 163 HII 01 25 04.0 -73 16 41           ~ 9 0
12 LHA 115-N 89 HII 01 25 53.9 -73 22 41           ~ 22 0
13 DEM S 165 HII 01 27 03.3 -73 08 32           ~ 7 0
14 SXP 1062 HXB 01 27 45.95 -73 32 56.3   14.32 14.36     B0.5(III)e 61 1
15 NAME SMC 1 Supergiant Shell HII 01 29 -73.3           ~ 14 0
16 DEM S 167 HII 01 29 09.9 -73 24 50           ~ 14 0
17 SK 183 * 01 29 24.5483246004 -73 33 16.344654688   13.57 13.80     O3V((f*))z+OB 13 0
18 DEM S 166 HII 01 29 26.8 -73 32 38           ~ 14 0
19 Bruck 164 Cl* 01 29 30 -73 32.0           ~ 13 0
20 LHA 115-N 90 HII 01 29 30.15 -73 33 10.5           ~ 57 1
21 NGC 602 Cl* 01 29 32.133 -73 33 38.13     13.018     ~ 81 1
22 Cl Lindsay 105 Cl* 01 29 34.82 -73 33 29.4           ~ 11 0
23 LIN 547 WR* 01 31 04.1366633984 -73 25 03.786377386   12.75 12.90     WO4+O4V 92 0
24 Cl Lindsay 107 As* 01 31 08.83 -73 24 51.1           ~ 22 0
25 SK 190 * 01 31 27.9846877393 -73 22 14.220864835   13.37 13.59     O7.5(f)np 15 0
26 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5249 1
27 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5863 1
28 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15205 1
29 LHA 120-N 206A HII 05 31 15.2 -71 03 58           ~ 99 2
30 RMC 136 Cl* 05 38 42.396 -69 06 03.36           ~ 1777 1

    Equat.    Gal    SGal    Ecl

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2021.03.03-02:07:32

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