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Related papers: B and Be stars in the Magellanic Clouds: rotation,…

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We report the discovery of 5 new Herbig Ae/Be candidate stars in the Small Magellanic Cloud in addition to the 2 reported in Beaulieu et al. (2001). We discuss these 7 HAeBe candidate stars in terms of (1) their irregular photometric…

Astrophysics · Physics 2009-11-10 W. J. de Wit , J-P. Beaulieu , H. J. G. L. M. Lamers , E. Lesquoy , J-B. Marquette , ;

Motivated by the detection of a recent outburst of the massive luminous blue variable LMC-R71, which reached an absolute magnitude M_V = -9.3 mag, we undertook a systematic study of the optical variability of 1268 massive stars in the Large…

Solar and Stellar Astrophysics · Physics 2015-03-13 D. M. Szczygiel , K. Z. Stanek , A. Z. Bonanos , G. Pojmanski , B. Pilecki , J. L. Prieto

Recent theoretical predictions for low metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and as such should retain most of their angular momentum.…

Astrophysics · Physics 2009-11-10 Laura R. Penny , Amanda J. Sprague , George Seago , Douglas R. Gies

Context: Stellar pulsations in main-sequence B-type stars are driven by the kappa-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B spectral domain at very low…

Astrophysics · Physics 2009-11-13 P. D. Diago , J. Gutierrez-Soto , J. Fabregat , C. Martayan

We show that Be stars belong to a high velocity tail of a single B-type star rotational velocity distribution in the MS. This implies that: 1) the number fraction N(Be)/N(Be+B) is independent of the mass; 2) Bn stars having ZAMS rotational…

Astrophysics · Physics 2016-08-15 J. Zorec , Y. Frémat , C. Martayan , L. Cidale , A. Torres

Be stars are a class of rapidly rotating B stars with circumstellar disks that cause Balmer and other line emission. There are three possible reasons for the rapid rotation of Be stars: they may have been born as rapid rotators, spun up by…

Astrophysics · Physics 2009-11-11 M. Virginia McSwain , Douglas R. Gies

We present new observations of 470 stars using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument in fields centered on the clusters NGC 330 and NGC 346 in the Small Magellanic Cloud (SMC), and NGC 2004 and the N11 region…

Astrophysics · Physics 2007-05-23 C. J. Evans , D. J. Lennon , S. J. Smartt , C. Trundle

[Abridged] We have studied the optical spectra of 28 O- and early B-type stars in the Large Magellanic Cloud, 22 of which are associated with the young star-forming region N11. Stellar parameters are determined using an automated fitting…

We present multiple epochs of H-alpha spectroscopy for 47 members of the open cluster NGC 3766 to investigate the long term variability of its Be stars. Sixteen of the stars in this sample are Be stars, including one new discovery. Of…

Recently the OGLE experiment has provided accurate light curves and colours for about 2 millions stars in the Small Magellanic Cloud. We have examined this database for its content of Be stars, applying some selection criteria, and we have…

Astrophysics · Physics 2009-11-07 R. E. Mennickent , G. Pietrzynski , W. Gieren , O. Szewczyk

Detailed studies of Be stars in environments with different metallicities like the Magellanic Clouds or the Galactic bulge are necessary to understand the formation and evolution mechanisms of the circumstellar disks. However, a detailed…

Astrophysics · Physics 2009-11-13 B. E. Sabogal , R. E. Mennickent , G. Pietrzyński , J. A. García , W. Gieren , Z. Kolaczkowski , .

I present measurements of the projected rotational velocities of a sample of 100 early B-type main-sequence stars in the Large Magellanic Cloud. This is the first extragalactic study of the distribution of stellar rotational velocities. The…

Astrophysics · Physics 2009-11-10 Stefan C. Keller

We present a study of the infrared properties of 4922 spectroscopically confirmed massive stars in the Large and Small Magellanic Clouds, focusing on the active OB star population. Besides OB stars, our sample includes yellow and red…

Spectroscopic monitoring of 141 southern field B type stars, 114 of them known to exhibit the Be phenomenon, allowed the estimation of their projected rotational velocities, effective temperatures and superficial gravities from…

Astrophysics · Physics 2009-11-11 R. S. Levenhagen , N. V. Leister

We present a catalogue of new spectral types for hot, luminous stars in the Small Magellanic Cloud. The catalogue contains 4161 objects, giving an order of magnitude increase in the number of SMC stars with published spectroscopic…

Astrophysics · Physics 2014-10-13 C. J. Evans , I. D. Howarth , M. J. Irwin , A. W. Burnley , T. J. Harries

We show the vsini distribution of main sequence B stars in sites of various metallicities, in the absolute magnitude range -3.34 < Mv < -2.17. These include Galactic stars in the field measured by Abt et al. (2002), members of the h & chi…

Astrophysics · Physics 2015-06-24 F. Royer , P. North , C. Melo , J. -C. Mermilliod , E. K. Grebel , J. R. de Medeiros , A. Maeder

This document presents the results from our spectroscopic survey of Halpha emitters in galactic and SMC open clusters with the ESO Wide Field Imager in its slitless spectroscopic mode. First of all, for the galactic open cluster NGC6611, in…

Astrophysics · Physics 2008-09-26 Christophe Martayan , Dietrich Baade , Juan Fabregat

At low metallicity the B-type stars rotate faster than at higher metallicity, typically in the SMC. As a consequence, it was expected a larger number of fast rotators in the SMC than in the Galaxy, in particular more Be/Oe stars. With the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Christophe Martayan , Dietrich Baade , Jean Zorec , Yves Fremat , Juan Fabregat , Sylvia Ekstrom

We present an analysis of high-resolution FLAMES spectra of approximately 50 early B-type stars in three young clusters at different metallicities, NGC6611 in the Galaxy, N11 in the Large Magellanic Cloud (LMC) and NGC346 in the Small…

The presence of an anomalously large population of Be stars in the young cluster NGC 330 in the SMC has been noted by Feast (1972), Bessell & Wood (1993), Grebel (1996) and most recently Keller et al. (1998). We present results from…

Astrophysics · Physics 2007-05-23 Stefan C. Keller , Michael S. Bessell