scholarly journals A WC9 Star in the LMC

1991 ◽  
Vol 143 ◽  
pp. 647-648
Author(s):  
M. Heydari-Malayeri ◽  
J. Melnick
Keyword(s):  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Late Type

We have discovered the only WC9 star in the Large Magellanic Cloud on the basis of observations made at several ESO telescopes, especially NTT. The latest Wolf-Rayet stars of the carbon sequence so far observed in the LMC are WC5-6. The lack of late type WC stars is understood in terms of an abundance effect, according to the models of Maeder. Our observations therefore pose a new observational challenge to the theory of the evolution of massive stars.

scholarly journals The VLT–FLAMES Tarantula Survey

2009 ◽  
Vol 5 (S266) ◽  
pp. 35-40 ◽  
Author(s):  
C. J. Evans ◽  
N. Bastian ◽  
Y. Beletsky ◽  
I. Brott ◽  
M. Cantiello ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Cluster Evolution ◽  
30 Doradus

AbstractThe Tarantula Survey is an ambitious ESO Large Programme that has obtained multi-epoch spectroscopy of over 1000 massive stars in the 30 Doradus region in the Large Magellanic Cloud. Here, we introduce the scientific motivations of the survey and give an overview of the observational sample. Ultimately, quantitative analysis of every star, paying particular attention to the effects of rotational mixing and binarity, will be used to address fundamental questions in both stellar and cluster evolution.

scholarly journals The Wolf–Rayet binaries of the nitrogen sequence in the Large Magellanic Cloud

2019 ◽  
Vol 627 ◽  
pp. A151 ◽  
Author(s):  
T. Shenar ◽  
D. P. Sablowski ◽  
R. Hainich ◽  
H. Todt ◽  
A. F. J. Moffat ◽  
...  
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Binary Interaction ◽  
Evolutionary Status ◽  
X Ray ◽  
Composite Spectra ◽  
The Impact

Context. Massive Wolf–Rayet (WR) stars dominate the radiative and mechanical energy budget of galaxies and probe a critical phase in the evolution of massive stars prior to core collapse. It is not known whether core He-burning WR stars (classical WR; cWR) form predominantly through wind stripping (w-WR) or binary stripping (b-WR). Whereas spectroscopy of WR binaries has so-far largely been avoided because of its complexity, our study focuses on the 44 WR binaries and binary candidates of the Large Magellanic Cloud (LMC; metallicity Z ≈ 0.5 Z⊙), which were identified on the basis of radial velocity variations, composite spectra, or high X-ray luminosities. Aims. Relying on a diverse spectroscopic database, we aim to derive the physical and orbital parameters of our targets, confronting evolution models of evolved massive stars at subsolar metallicity and constraining the impact of binary interaction in forming these stars. Methods. Spectroscopy was performed using the Potsdam Wolf–Rayet (PoWR) code and cross-correlation techniques. Disentanglement was performed using the code Spectangular or the shift-and-add algorithm. Evolutionary status was interpreted using the Binary Population and Spectral Synthesis (BPASS) code, exploring binary interaction and chemically homogeneous evolution. Results. Among our sample, 28/44 objects show composite spectra and are analyzed as such. An additional five targets show periodically moving WR primaries but no detected companions (SB1); two (BAT99 99 and 112) are potential WR + compact-object candidates owing to their high X-ray luminosities. We cannot confirm the binary nature of the remaining 11 candidates. About two-thirds of the WN components in binaries are identified as cWR, and one-third as hydrogen-burning WR stars. We establish metallicity-dependent mass-loss recipes, which broadly agree with those recently derived for single WN stars, and in which so-called WN3/O3 stars are clear outliers. We estimate that 45  ±  30% of the cWR stars in our sample have interacted with a companion via mass transfer. However, only ≈12  ±  7% of the cWR stars in our sample naively appear to have formed purely owing to stripping via a companion (12% b-WR). Assuming that apparently single WR stars truly formed as single stars, this comprises ≈4% of the whole LMC WN population, which is about ten times less than expected. No obvious differences in the properties of single and binary WN stars, whose luminosities extend down to log L ≈ 5.2 [L⊙], are apparent. With the exception of a few systems (BAT99 19, 49, and 103), the equatorial rotational velocities of the OB-type companions are moderate (veq ≲ 250 km s−1) and challenge standard formalisms of angular-momentum accretion. For most objects, chemically homogeneous evolution can be rejected for the secondary, but not for the WR progenitor. Conclusions. No obvious dichotomy in the locations of apparently single and binary WN stars on the Hertzsprung-Russell diagram is apparent. According to commonly used stellar evolution models (BPASS, Geneva), most apparently single WN stars could not have formed as single stars, implying that they were stripped by an undetected companion. Otherwise, it must follow that pre-WR mass-loss/mixing (e.g., during the red supergiant phase) are strongly underestimated in standard stellar evolution models.

scholarly journals Massive Stars in the Tarantula Nebula: A Rosetta Stone for Extragalactic Supergiant HII Regions

Galaxies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 88 ◽  
Author(s):  
Paul A. Crowther
Keyword(s):  
Massive Stars ◽  
Hii Regions ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
High Mass ◽  
Stellar Content ◽  
X Ray ◽  
Star Forming ◽  
Rosetta Stone ◽  
The Individual

A review of the properties of the Tarantula Nebula (30 Doradus) in the Large Magellanic Cloud is presented, primarily from the perspective of its massive star content. The proximity of the Tarantula and its accessibility to X-ray through radio observations permit it to serve as a Rosetta Stone amongst extragalactic supergiant HII regions since one can consider both its integrated characteristics and the individual properties of individual massive stars. Recent surveys of its high mass stellar content, notably the VLT FLAMES Tarantula Survey (VFTS), are reviewed, together with VLT/MUSE observations of the central ionizing region NGC 2070 and HST/STIS spectroscopy of the young dense cluster R136, provide a near complete Hertzsprung-Russell diagram of the region, and cumulative ionizing output. Several high mass binaries are highlighted, some of which have been identified from a recent X-ray survey. Brief comparisons with the stellar content of giant HII regions in the Milky Way (NGC 3372) and Small Magellanic Cloud (NGC 346) are also made, together with Green Pea galaxies and star forming knots in high-z galaxies. Finally, the prospect of studying massive stars in metal poor galaxies is evaluated.

scholarly journals SPITZERVIEW OF YOUNG MASSIVE STARS IN THE LARGE MAGELLANIC CLOUD H II COMPLEXES. II. N 159

2010 ◽  
Vol 721 (2) ◽  
pp. 1206-1232 ◽  
Author(s):  
C.-H. Rosie Chen ◽  
Remy Indebetouw ◽  
You-Hua Chu ◽  
Robert A. Gruendl ◽  
Gérard Testor ◽  
...  
Keyword(s):  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud

Massive Binaries in the Magellanic Clouds

2005 ◽  
Vol 13 ◽  
pp. 463-463
Author(s):  
Virpi S. Niemela
Keyword(s):  
Binary Stars ◽  
Present Status ◽  
Binary Systems ◽  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Stellar Winds ◽  
Multiple Systems ◽  
Orbital Parameters

We present results of our ongoing observing program on search and studies of massive stars (O and WR type) in binary systems in our neighbor galaxies, the Magellanic Clouds. Radial velocity orbits are presented for two new binaries, one in the Small Magellanic Cloud and another in the Large Magellanic Cloud, and improved orbits for previously known systems. We compare orbital parameters of selected binaries containing O and WR type components. We also discuss the present status of knowledge for massive binary stars in the Magellanic Clouds and the problems encountered in their orbital studies such as stellar winds the ubiquitous tendency to be born in multiple systems.

scholarly journals SPITZERSAGE INFRARED PHOTOMETRY OF MASSIVE STARS IN THE LARGE MAGELLANIC CLOUD

2009 ◽  
Vol 138 (4) ◽  
pp. 1003-1021 ◽  
Author(s):  
A. Z. Bonanos ◽  
D. L. Massa ◽  
M. Sewilo ◽  
D. J. Lennon ◽  
N. Panagia ◽  
...  
Keyword(s):  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Infrared Photometry

scholarly journals A precise and accurate distance to the Large Magellanic Cloud from late-type eclipsing-binary systems

2012 ◽  
Vol 8 (S289) ◽  
pp. 169-172
Author(s):  
G. Pietrzyński ◽  
W. Gieren ◽  
D. Graczyk ◽  
I. Thompson ◽  
B. Pilecki ◽  
...  
Keyword(s):  
Binary Systems ◽  
Zero Point ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Distance Scale ◽  
Late Type ◽  
Eclipsing Binary ◽  
Extragalactic Distance Scale

AbstractWe present a precise and accurate measurement of the distance to the Large Magellanic Cloud based on late-type eclipsing-binary systems. Our results provide curently the most accurate zero point for the extragalactic distance scale.

scholarly journals Feedback from massive stars at low metallicities: MUSE observations of N44 and N180 in the Large Magellanic Cloud

2018 ◽  
Vol 486 (4) ◽  
pp. 5263-5288 ◽  
Author(s):  
A F McLeod ◽  
J E Dale ◽  
C J Evans ◽  
A Ginsburg ◽  
J M D Kruijssen ◽  
...  
Keyword(s):  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud

Ejected Nebulae as Probes of the Evolution of Massive Stars in the Large Magellanic Cloud

1998 ◽  
Vol 503 (1) ◽  
pp. 278-296 ◽  
Author(s):  
Linda J. Smith ◽  
Antonella Nota ◽  
Anna Pasquali ◽  
Claus Leitherer ◽  
Mark Clampin ◽  
...  
Keyword(s):  
Massive Stars ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud

scholarly journals The Stellar Population of R136

1999 ◽  
Vol 190 ◽  
pp. 217-221
Author(s):  
Deidre A. Hunter
Keyword(s):  
Stellar Population ◽  
Massive Stars ◽  
Compact Star ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Star Cluster

The luminous, compact star cluster R136 in the Large Magellanic Cloud is 300 times more spatially concentrated than a typical OB association and contains at least 39 O3 stars, the most massive of which is ~150 M⊙. Yet, the stellar IMF for 2.8–120 M⊙ is normal. The massive stars are 1–2 Myrs old, and Wolf-Rayet stars are not evolved.

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