J/A+A/680/A32 NGC 330 seen by MUSE III. (Bodensteiner+, 2023)
The young massive SMC cluster NGC 330 seen by MUSE.
III. Stellar parameters and rotational velocities.
Bodensteiner J., Sana H., Dufton P.L., Wang C., Langer N., Banyard G.,
Mahy L., de Koter A., de Mink S.E., Evans C.J., Goetberg Y.,
Henault-Brunet V., Patrick L.R., Schneider F.R.N.
<Astron. Astrophys. 680, A32 (2023)>
=2023A&A...680A..32B 2023A&A...680A..32B (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Clusters, open ; Rotational velocities ;
Optical ; Infrared
Keywords: stars: early-type - emission-line, Be -
stars: fundamental parameters - Hertzsprung-Russell and C-M diagrams -
Magellanic Clouds
Abstract:
The origin of initial rotation rates of stars, and how a star's
surface rotational velocity changes during the evolution, either by
internal angular momentum transport or due to interactions with a
binary companion, remain open questions in stellar astrophysics.
Here, we aim to derive the physical parameters and study the
distribution of (projected) rotational velocities of B-type stars in
the 35 Myr-old, massive cluster NGC 330 in the Small Magellanic Cloud.
NGC 330 is in an age range where the number of post-interaction
binaries is predicted to be high near the cluster turnoff (TO). We
develop a simultaneous photometric and spectroscopic grid-fitting
method adjusting atmosphere models on multi-band Hubble Space
Telescope photometry and Multi Unit Spectroscopic Explorer
spectroscopy. This allows us to homogeneously constrain the physical
parameters of over 250 B and Be stars, brighter than mF814W=18.8mag.
The rotational velocities of Be stars in NGC 330 are significantly
higher than the ones of B stars. The rotational velocities vary as a
function of the star's position in the color-magnitude diagram,
qualitatively following predictions of binary population synthesis. A
comparison to younger clusters shows that stars in NGC 330 rotate more
rapidly on average.
The rotational velocities of the 35Myr old population in NGC 330
quantitatively agree with predictions for a stellar population that
underwent significant binary interactions: the bulk of the B stars
could be single stars or primaries in pre-interaction binaries. The
rapidly spinning Be stars could be mass and angular momentum gainers
in previous interactions, while those Be stars close to the TO may be
spun-up single stars. The slowly rotating, apparently single stars
above the TO could be merger products. The different
vsini-characteristics of NGC 330 compared to younger populations can
be understood in this framework.
Description:
We have measured the stellar parameters of the presumably single stars
and SB1s in NGC 330. For this purpose we used the available HST
photometry as well as spectra that were combined from the six observed
MUSE epochs. We determined stellar parameters with a two-component
grid-search approach using the BSTAR2006 tlusty grid of model
atmospheres.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 108 282 Compilation of all parameters derived for the
sample stars
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See also:
J/A+A/634/A51 : NGC 330 seen by MUSE I. (Bodensteiner+, 2020)
J/A+A/652/A70 : NGC 330 seen by MUSE II. (Bodensteiner+, 2021)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [10/732] Identification number
5- 13 F9.6 deg RAdeg Right ascension (J2000)
15- 24 F10.6 deg DEdeg Declination (J2000)
26- 29 F4.1 mag F336W F336W magnitude from (Milone et al.,
2018MNRAS.477.2640M 2018MNRAS.477.2640M)
31- 34 F4.1 mag F814W F814W magnitude from (Milone et al.,
2018MNRAS.477.2640M 2018MNRAS.477.2640M)
36- 39 A4 --- SpType Spectral type
41- 45 I5 K Teff Effective temperature Teff
47- 50 I4 K E_Teff ?=- Effective temperature, upper error
52- 55 I4 K e_Teff ?=- Effective temperature, lower error
57- 59 F3.1 [cm/s2] logg Surface gravity logg
61- 63 F3.1 [cm/s2] E_logg ?=- Surface gravity, upper error
65- 67 F3.1 [cm/s2] e_logg ?=- Surface gravity, lower error
69- 71 I3 km/s vsini Projected rotational velocity vsini
73- 75 I3 km/s E_vsini ?=- Projected rotational velocity, upper error
77- 79 I3 km/s e_vsini ?=- Projected rotational velocity, lower error
81- 84 F4.1 Rsun Rad Radius
86- 88 F3.1 Rsun E_Rad ?=- Radius, upper error
90- 92 F3.1 Rsun e_Rad ?=- Radius, lower error
94- 96 F3.1 Lsun Lum Luminosity
98-100 F3.1 Lsun E_Lum ?=- Luminosity, upper error
102-104 F3.1 Lsun e_Lum ?=- Luminosity, lower error
106-108 A3 --- Flag Binary flag (1)
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Note (1): Binary flag as follows:
SB1 = flagged as binary based on RV variability
SB2 = composite SB2 spectrum
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Acknowledgements:
Julia Bodensteiner, julia.bodensteiner(at)eso.org
References:
Bodensteiner et al., Paper I 2020A&A...634A..51B 2020A&A...634A..51B, Cat. J/A+A/634/A51
Bodensteiner et al., Paper II 2021A&A...652A..70B 2021A&A...652A..70B, Cat. J/A+A/652/A70
(End) Patricia Vannier [CDS] 12-Oct-2023