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Related papers: Be-star rotation: how close to critical?

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The rotation rate of a star has important implications for the detectability, characterisation and stability of any planets that may be orbiting it. This chapter gives a brief overview of stellar rotation before describing the methods used…

Earth and Planetary Astrophysics · Physics 2018-12-05 P. F. L. Maxted

The interpretation of stellar apparent fundamental parameters must be treated consistently with the characteristics of their surface rotation law. We develop a model to determine the distribution of the effective temperature and gravity,…

Solar and Stellar Astrophysics · Physics 2017-10-04 J. Zorec , M. Rieutord , F. Espinosa Lara , Y. Frémat , A. Domiciano de Souza , F. Royer

Raytracing computations for light emitted from the surface of a rapidly rotating neutron star are carried out in order to construct light curves for accreting millisecond pulsars. These calculations are for realistic models of rapidly…

Astrophysics · Physics 2007-05-23 D. Leahy , S. Morsink , C. Cadeau

We investigate the prospects for characterizing extrasolar giant planets by measuring planetary oblateness from transit photometry and inferring planetary rotational periods. The rotation rates of planets in the solar system vary widely,…

Astrophysics · Physics 2009-11-07 Jason W. Barnes , Jonathan J. Fortney

Among the emission-line stars, the classical Be stars known for their extreme properties are remarkable. The Be stars are B-type main sequence stars that have displayed at least once in their life emission lines in their spectrum. Beyond…

Solar and Stellar Astrophysics · Physics 2015-05-20 Christophe Martayan , Thomas Rivinius , Dietrich Baade , Anne-Marie Hubert , Jean Zorec

Recent photometric analysis of the colour-magnitude diagrams (CMDs) of young massive clusters (YMCs) have found evidence for splitting in the main sequence and extended main sequence turn-offs, both of which have been suggested to be caused…

Astrophysics of Galaxies · Physics 2017-01-11 N. Bastian , I. Cabrera-Ziri , F. Niederhofer , S. de Mink , C. Georgy , D. Baade , M. Correnti , C. Usher , M. Romaniello

We numerically investigate the possibility of planetesimal accretion in circumbinary disks, under the coupled influence of both stars' secular perturbations and friction due to the gaseous component of the protoplanetary disk. We focus on…

Astrophysics · Physics 2009-11-13 Hans Scholl , Francesco Marzari , Philippe Thebault

In this lecture I discuss the bulk surface heterogeneity of rotating stars, namely gravity darkening. I especially detail the derivation of the omega-model of Espinosa Lara & Rieutord (2011), which gives the gravity darkening in early-type…

Solar and Stellar Astrophysics · Physics 2016-09-07 Michel Rieutord

We analyzed the behavior of the rotational velocity in the parent stars of extrasolar planets. Projected rotational velocity v sin i and angular momentum were combined with stellar and planetary parameters, for a unique sample of 147 stars,…

Solar and Stellar Astrophysics · Physics 2010-07-05 Sanzia Alves , Jose Dias do Nascimento , Jose Renan de Medeiros

Studies of beryllium abundance in large samples of solar-type stars show a small fraction of extremely beryllium-deficient stars, which challenges our current understanding of light element depletion in these stars. We suggest two possible…

Solar and Stellar Astrophysics · Physics 2015-06-11 M. Viallet , I. Baraffe

We examine claims of strong gravity-darkening effects in the O-star components of WR+O binaries. We generate synthetic spectra for a wide range of parameters, and show that the line-width results are consistent with extensive measurements…

Solar and Stellar Astrophysics · Physics 2018-05-23 Dominic Reeve , Ian D. Howarth

The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. The unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for…

While galaxy rotation curves provide one of the most powerful methods for measuring dark matter profiles in the inner regions of rotation-supported galaxies, at the dwarf scale there are factors that can complicate this analysis. Given the…

The orbits of binary stars precess as a result of general relativistic effects, forces arising from the asphericity of the stars, and forces from additional stars or planets in the system. For most binaries, the theoretical and observed…

Solar and Stellar Astrophysics · Physics 2015-05-14 Simon Albrecht , Sabine Reffert , Ignas A. G. Snellen , Joshua N. Winn

We present the results of a spectroscopic investigation of 108 nearby field B-stars. We derive their key stellar parameters, $V \sin i$, $T_{\rm eff}$, $\log g$, and $\log g_{\rm polar}$, using the same methods that we used in our previous…

Astrophysics · Physics 2009-11-13 Wenjin Huang , Douglas R. Gies

An improved formula for the timing of binary pulsars that accounts for the relativistic deflection of light in the gravitational field of the pulsar's companion is presented, and the measurability of this effect together with its variance…

Astrophysics · Physics 2015-06-24 Oleg Doroshenko , Sergei Kopeikin

In previous works of this series, we have shown that late B- and early A-type stars have genuine bimodal distributions of rotational velocities and that late A-type stars lack slow rotators. The distributions of the surface angular velocity…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. Zorec , F. Royer

We show that Be stars belong to a high velocity tail of a single B-type star rotational velocity distribution in the main sequence (MS). We studied 127 galactic field Be stars and obtained their true equatorial velocity at the ZAMS using…

Astrophysics · Physics 2007-05-23 Juan Zorec , Christophe Martayan , Yves Fremat , Anne-Marie Hubert , Michele Floquet

The influence of rotation on the dynamical evolution of collisional stellar systems is investigated by solving the orbit-averaged Fokker-Planck equation in (E,J_z)-space. We find that large amounts of initial rotation drive the system into…

Astrophysics · Physics 2007-05-23 Ch. Einsel , R. Spurzem

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
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