J/A+A/648/A65 The sHRD of OB stars in NGC 2070 (Castro+, 2021)
Mapping the core of the Tarantula Nebula with VLT-MUSE.
II. The spectroscopic Hertzsprung-Russell diagram of OB stars in NGC 2070.
Castro N., Crowther P.A., Evans C.J., Vink J.S., Puls J., Herrero A.,
Garcia M., Selman F.J., Roth M.M., Simon-Diaz S.
<Astron. Astrophys. 648, A65 (2021)>
=2021A&A...648A..65C 2021A&A...648A..65C (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Clusters, open ; Stars, early-type ;
Stars, OB ; Stars, masses ; Effective temperatures
Keywords: stars: early-types - stars: fundamental parameters -
galaxies: star clusters: individual: NGC 2070 - Magellanic Clouds
Abstract:
We present the spectroscopic analysis of 333 OB-type stars
extracted from VLT-MUSE observations of the central 30x30pc of
NGC 2070 in the Tarantula Nebula on the Large Magellanic Cloud, the
majority of which are analysed for the first time. The distribution of
stars in the spectroscopic Hertzsprung-Russell diagram (sHRD) shows
281 stars in the main sequence. We find two groups in the main
sequence, with estimated ages of 2.1±0.8 and 6.2±2Myr. A subgroup
of 52 stars is apparently beyond the main sequence phase, which we
consider to be due to emission-type objects and/or significant nebular
contamination affecting the analysis. As in previous studies, stellar
masses derived from the sHRD are systematically larger than those
obtained from the conventional HRD, with the differences being largest
for the most massive stars. Additionally, we do not find any trend
between the estimated projected rotational velocity and evolution in
the sHRD. The projected rotational velocity distribution presents a
tail of fast rotators that resembles findings in the wider population
of 30 Doradus. We use published spectral types to calibrate the
HeIλ4921/HeIIλ5411 equivalent-width ratio as a
classification diagnostic for early-type main sequence stars when the
classical blue-visible region is not observed. Our model-atmosphere
analyses demonstrate that the resulting calibration is well correlated
with effective temperature.
Description:
Estimated physical parameters of the 281 early-type stars with
logTeff[K]>4.3 in NGC 2070 from the MUSE observations sorted by
effective temperature. See section 3 in the publication for a
description of the analysis and limitations in the listed parameters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 91 281 OB sample in NGC2070 analysed in this work
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See also:
J/A+A/614/A147 : NGC 2070 point sources radial velocities (Castro+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- MUSE Identification and coordinates from
Castro et al. (2018A&A...614A.147C 2018A&A...614A.147C, Cat.
J/A+A/614/A147), [CCE2018] NNNN in Simbad
6 I1 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 16 F6.3 s RAs Right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Declination (J2000)
22- 23 I2 arcmin DEm Declination (J2000)
25- 30 F6.3 arcsec DEs Declination (J2000)
32- 35 F4.2 [K] logTeff log effective temperature
37- 40 F4.2 [K] e_logTeff rms uncertainty in logTeff
42- 45 F4.2 [Lsun] logLs log spectroscopic luminosity (1)
47- 50 F4.2 [Lsun] e_logLs rms uncertainty in logLs
52- 55 F4.2 [Lsun] logL log luminosity
57- 60 F4.2 [Lsun] e_logL rms uncertainty in logL
62- 64 F3.1 mag Av Extinction
66- 70 F5.2 mag Vmag Visual magnitude
(Castro et al., 2018A&A...614A.147C 2018A&A...614A.147C)
71 A1 --- Note [*] Note (2)
73- 75 I3 [Msun] logMassLs ?=- log estimated mass in the
spectroscopic Hertzsprung-Russell
diagram (sHRD)(1) (3)
77- 78 I2 [Msun] logMassL ?=- log estimated mass in the
Hertzsprung-Russell diagram (HRD) (3)
80- 84 F5.2 Myr AgeLs ?=- Age estimated from positions in the
sHRD (1) (3)
86- 88 I3 km/s vsini Projected rotational velocity
90- 91 A2 --- SpType Spectral types derived according to the
HeI 4921 to HeII 5411 ratio
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Note (1): The spectroscopic luminosity and the spectroscopic Hertzsprung-Russell
diagram (sHRD) are defined in Langer & Kudritzki (2014A&A...564...52L 2014A&A...564...52L)
See also Castro et al. (2014A&A...570...13C 2014A&A...570...13C)
Note (2): * for the thirteen stars included in this work not listed in
Castro et al., 2018A&A...614A.147C 2018A&A...614A.147C).
Note (3): Masses and ages are estimated from comparisons with evolutionary
models from Koehler et al. (2015A&A...573A..71K 2015A&A...573A..71K, Cat. J/A+A/573/A71).
Stars outside of the evolutionary track boundaries are not considered in
the analysis ('---').
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Acknowledgements:
NC gratefully acknowledge funding from the
Deutsche Forschungsgemeinschaft (DFG) - CA 2551/1-1. SS-D and AHD
acknowledge support from the Spanish Government Ministerio de Ciencia
e Innovacion through grants PGC-2018-091 3741-B-C22 and
CEX2019-000920-S, and from the Canarian Agency for Research,
Innovation and Information Society (ACIISI), of the Canary Islands
Government, and the European Regional Development Fund (ERDF), under
grant with reference ProID2020010016.
From Norberto Castro Rodriguez, ncastro(at)aip.de,
[Leibniz-Institut fuer Astrophysik Potsdam (AIP)
References:
Castro et al., Paper I 2018A&A...614A.147C 2018A&A...614A.147C, Cat. J/A+A/614/A147
(End) Norberto Castro [AIP], Patricia Vannier [CDS] 18-Feb-2021