The H-R diagram of the Large Magellanic Cloud and implications for stellar evolution

1990 ◽  
Vol 363 ◽  
pp. 119 ◽  
Author(s):  
Edward L. Fitzpatrick ◽  
Catharine D. Garmany
Keyword(s):  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud

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.

Testing Intermediate-Age Stellar Evolution Models with VLT Photometry of Large Magellanic Cloud Clusters. II. Analysis with the Yale Models

2003 ◽  
Vol 125 (2) ◽  
pp. 754-769 ◽  
Author(s):  
Jong-Hak Woo ◽  
Carme Gallart ◽  
Pierre Demarque ◽  
Sukyoung Yi ◽  
Manuela Zoccali
Keyword(s):  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Cloud Clusters

scholarly journals The Characteristics of the Field RR Lyrae Stars in the Magellanic Clouds

1974 ◽  
Vol 59 ◽  
pp. 107-108
Author(s):  
J. A. Graham
Keyword(s):  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Light Curves ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
First Results ◽  
Lyrae Stars

The Magellanic Clouds are well known as being very suitable for observing the various stages of stellar evolution. During the last few years, I have been studying the RR Lyrae variable stars in each of the two Clouds. Some first results were reported at IAU Colloquium No. 21 in 1972 (Graham, 1973). Here, I would like to update these results on the basis of more recent data and to comment on some of the characteristics of the field RR Lyrae stars in each system. Periods and light curves are now available for 63 RR Lyrae stars in a 1° x 1.3° field centered on the cluster NGC 1783 in the Large Magellanic Cloud (LMC) and for 62 stars in a 1° x 1.3° field centered on the cluster NGC 121 in the Small Magellanic Cloud (SMC). Both ab and c type variables are represented and, viewed individually, the Cloud RR Lyraes are identical in characteristics to those known in our Galaxy. Studied as groups, however, there are small but significant differences between the RR Lyrae stars in each system. The following four specific features seem to be emerging from the study.

scholarly journals Large Magellanic Cloud Carbon Stars: Reading the Rosetta Stone of Stellar Evolution

2000 ◽  
Vol 177 ◽  
pp. 41-50
Author(s):  
Jay A. Frogel ◽  
Edgardo Costa
Keyword(s):  
Star Formation ◽  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Spatial Gradient ◽  
Carbon Stars ◽  
Rosetta Stone ◽  
Theoretical Predictions ◽  
Effective Temperatures

We discuss new results based on RI and JHK photometry for 888 and 204 carbon stars, respectively, of the 1035 C stars found by Blanco and his collaborators in the Large Magellanic Cloud (LMC). Bolometric magnitudes and effective temperatures for these stars are calculated and compared with theoretical predictions. We find a spatial gradient in the transition luminosity between M and C type stars. This has implications for the age of the most recent major epoch of star formation in the LMC.

scholarly journals Testing Intermediate-Age Stellar Evolution Models with VLT Photometry of Large Magellanic Cloud Clusters. I. The Data

2003 ◽  
Vol 125 (2) ◽  
pp. 742-753 ◽  
Author(s):  
Carme Gallart ◽  
Manuela Zoccali ◽  
Gianpaolo Bertelli ◽  
Cesare Chiosi ◽  
Pierre Demarque ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Cloud Clusters

scholarly journals Testing Intermediate-Age Stellar Evolution Models with VLT Photometry of Large Magellanic Cloud Clusters. III. Padova Results

2003 ◽  
Vol 125 (2) ◽  
pp. 770-784 ◽  
Author(s):  
Gianpaolo Bertelli ◽  
Emma Nasi ◽  
Leo Girardi ◽  
Cesare Chiosi ◽  
Manuela Zoccali ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Cloud Clusters

scholarly journals Methods to Identify Star Clusters in The Large Magellanic Cloud (LMC)

2018 ◽  
Vol 17 (1) ◽  
pp. 57-73
Author(s):  
Prasantha K Nayak ◽  
Annapurni Subramaniam
Keyword(s):  
Stellar Evolution ◽  
Large Fraction ◽  
Cluster Formation ◽  
Star Clusters ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Star Formation History ◽  
Optical Data ◽  
Formation History ◽  
The Galaxy

The Large Magellanic Cloud (LMC) hosts a few thousand star clusters which are ideal tools to study stellar evolution, star formation history, cluster formation and dissolution processes in the galaxy. Although many surveys (like IRSF, OGLE II etc) of the LMC have been carried out, a large fraction of clusters, mainly poor ones are yet to be identified. Also, the parameters of already identified clusters are not well studied. In this context, we have  tried to explore that among the available and upcoming surveys which survey (optical/NIR) can be used to efficiently detect and study the clusters in the LMC. We have found that the available OGLE-III optical data is ideal for this purpose, but only for young clusters, whereas Deeper optical data from DECAM survey, OGLE-IV and skymapper are ideal to study poor and old clusters. We have also found that one can combine  the ongoing VISTA data with upcoming optical data (OGLE IV) and estimate the cluster parameters more accurately.

scholarly journals Revisiting the Hunter diagram with the Geneva Stellar Evolution Code

2014 ◽  
Vol 9 (S307) ◽  
pp. 142-143
Author(s):  
R. Simoniello ◽  
G. Meynet ◽  
S. Ekström ◽  
C. Georgy ◽  
A. Granada
Keyword(s):  
Chemical Composition ◽  
Stellar Evolution ◽  
Initial Velocity ◽  
Main Sequence ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Main Sequence Stars ◽  
Star Evolution ◽  
Initial Chemical Composition ◽  
Stellar Masses

AbstractWe produced a model grid of rotating main and post-main sequence stars with the Geneva Stellar Evolution Code (GENEC). The initial chemical composition is tailored to compare with observations of early OB type stars in the Large Magellanic Cloud (LMC) and the grid covers stellar masses in the range of 7 ≤ M/M⊙ ≤ 15 and initial velocity between 0 km s−1 ≤ v sin(i) ≤ 300 km s−1. The model grid has been used to determine the changes in the surface Nitrogen abundances during the star evolution and the results have been compared with observations.

Supernova neutrinos: a summary

1994 ◽  
Vol 346 (1678) ◽  
pp. 85-91
Keyword(s):  
Elementary Particle ◽  
Stellar Evolution ◽  
Particle Physics ◽  
Supernova Explosion ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Elementary Particle Physics ◽  
Supernova Neutrinos

The detection of neutrinos from the supernova explosion SN1987A, and its significance for models of stellar evolution and for elementary particle physics are reviewed. Consideration is also given to the physics th a t could be learnt from such an explosion occurring closer than th a t of the Large Magellanic Cloud, the site of the 1987 explosion

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