scholarly journals Evolution of rotation in rapidly rotating early-type stars during the main sequence with 2D models

2019 ◽  
Vol 625 ◽  
pp. A89 ◽  
Author(s):  
D. Gagnier ◽  
M. Rieutord ◽  
C. Charbonnel ◽  
B. Putigny ◽  
F. Espinosa Lara
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Main Sequence ◽  
Massive Stars ◽  
Early Type ◽  
Wind Regime ◽  
Momentum Loss ◽  
Angular Momentum Loss ◽  
Rotational Evolution ◽  
Early Type Stars

The understanding of the rotational evolution of early-type stars is deeply related to that of anisotropic mass and angular momentum loss. In this paper, we aim to clarify the rotational evolution of rapidly rotating early-type stars along the main sequence (MS). We have used the 2D ESTER code to compute and evolve isolated rapidly rotating early-type stellar models along the MS, with and without anisotropic mass loss. We show that stars with Z = 0.02 and masses between 5 and 7 M⊙ reach criticality during the main sequence provided their initial angular velocity is larger than 50% of the Keplerian one. More massive stars are subject to radiation-driven winds and to an associated loss of mass and angular momentum. We find that this angular momentum extraction from the outer layers can prevent massive stars from reaching critical rotation and greatly reduce the degree of criticality at the end of the MS. Our model includes the so-called bi-stability jump of the Ṁ − Teff relation of 1D-models. This discontinuity now shows up in the latitude variations of the mass-flux surface density, endowing rotating massive stars with either a single-wind regime (no discontinuity) or a two-wind regime (a discontinuity). In the two-wind regime, mass loss and angular momentum loss are strongly increased at low latitudes inducing a faster slow-down of the rotation. However, predicting the rotational fate of a massive star is difficult, mainly because of the non-linearity of the phenomena involved and their strong dependence on uncertain prescriptions. Moreover, the very existence of the bi-stability jump in mass-loss rate remains to be substantiated by observations.

scholarly journals Mass-Loss From Spinning Stars

1980 ◽  
Vol 5 ◽  
pp. 601-613
Author(s):  
S. R. Sreenivasan
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Massive Stars ◽  
Stellar Winds ◽  
Late Type ◽  
Momentum Loss ◽  
Adequate Understanding ◽  
Angular Momentum Loss ◽  
Evolutionary Consequences ◽  
Acceptable Theory

AbstractThe effects of mass-loss and angular momentum loss on the evolution of massive stars are discussed bringing out the main results as well as the limitations of recent studies. It is pointed out that an acceptable theory of stellar winds in early as well as late type stars is needed as well as a satisfactory assessment of a number of instabilities in these contexts for an adequate understanding of the evolutionary consequences for a wide variety of population I and polulation II stars, which are affected by mass-loss.

scholarly journals Centrifugally driven mass-loss and outbursts of massive stars

2020 ◽  
Vol 495 (1) ◽  
pp. 249-265 ◽  
Author(s):  
Xihui Zhao ◽  
Jim Fuller
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Stellar Evolution ◽  
Main Sequence ◽  
Massive Stars ◽  
Variable Stars ◽  
Be Stars ◽  
Rotational Evolution ◽  
Break Up ◽  
Ultimate Fate

ABSTRACT Rotation and mass-loss are crucially interlinked properties of massive stars, strongly affecting their evolution and ultimate fate. Massive stars rotating near their break-up limit shed mass centrifugally, creating Be stars with circumstellar discs and possibly driving outbursts. Using the mesa stellar evolution code, we examine the effects of efficient angular momentum transport on the main-sequence and post-main-sequence rotational evolution of massive stars. In rapid rotators, angular momentum transported from the contracting core to the expanding envelope can spin-up the surface layers past the break-up rate, particularly for stars near (or beyond) the end of the main-sequence and in low-metallicity environments. We also demonstrate that centrifugal instabilities could arise in rapidly rotating massive stars, potentially triggering the S Doradus outbursts observed in luminous blue variable stars. Prior mass accretion from a binary companion increases both the likelihood and the intensity of centrifugal mass-loss. We discuss implications for massive stellar evolution, Be stars, and luminous blue variables.

scholarly journals Angular momentum loss and stellar spin-down in magnetic massive stars

2008 ◽  
Vol 4 (S259) ◽  
pp. 423-424
Author(s):  
Asif ud-Doula ◽  
Stanley P. Owocki ◽  
Richard H.D. Townsend
Keyword(s):  
Angular Momentum ◽  
Massive Stars ◽  
Solid Angle ◽  
Magnetic Confinement ◽  
Dipole Field ◽  
Hot Stars ◽  
Momentum Loss ◽  
Dipole Magnetic Field ◽  
Angular Momentum Loss ◽  
Compare And Contrast

AbstractWe examine the angular momentum loss and associated rotational spin-down for magnetic hot stars with a line-driven stellar wind and a rotation-aligned dipole magnetic field. Our analysis here is based on our previous 2-D numerical MHD simulation study that examines the interplay among wind, field, and rotation as a function of two dimensionless parameters, W(=Vrot/Vorb) and ‘wind magnetic confinement’, η∗ defined below. We compare and contrast the 2-D, time variable angular momentum loss of this dipole model of a hot-star wind with the classical 1-D steady-state analysis by Weber and Davis (WD), who used an idealized monopole field to model the angular momentum loss in the solar wind. Despite the differences, we find that the total angular momentum loss averaged over both solid angle and time follows closely the general WD scaling ~ ṀΩR2A. The key distinction is that for a dipole field Alfvèn radius RA is significantly smaller than for the monopole field WD used in their analyses. This leads to a slower stellar spin-down for the dipole field with typical spin-down times of order 1 Myr for several known magnetic massive stars.

scholarly journals The properties of early-type stars in the Magellanic Clouds

2008 ◽  
Vol 4 (S256) ◽  
pp. 325-336
Author(s):  
Christopher J. Evans
Keyword(s):  
Physical Properties ◽  
Mass Loss ◽  
Temperature Scale ◽  
Massive Stars ◽  
Magellanic Clouds ◽  
Early Type ◽  
The Past ◽  
The Galaxy ◽  
Stellar Temperature ◽  
Early Type Stars

AbstractThe past decade has witnessed impressive progress in our understanding of the physical properties of massive stars in the Magellanic Clouds, and how they compare to their cousins in the Galaxy. I summarise new results in this field, including evidence for reduced mass-loss rates and faster stellar rotational velocities in the Clouds, and their present-day compositions. I also discuss the stellar temperature scale, emphasizing its dependence on metallicity across the entire upper-part of the Hertzsprung-Russell diagram.

scholarly journals The VLT-FLAMES survey of massive stars: mass loss and rotation of early-type stars in the SMC

2006 ◽  
Vol 456 (3) ◽  
pp. 1131-1151 ◽  
Author(s):  
M. R. Mokiem ◽  
A. de Koter ◽  
C. J. Evans ◽  
J. Puls ◽  
S. J. Smartt ◽  
...  
Keyword(s):  
Mass Loss ◽  
Massive Stars ◽  
Early Type ◽  
Early Type Stars

scholarly journals The effects of surface fossil magnetic fields on massive star evolution – II. Implementation of magnetic braking in mesa and implications for the evolution of surface rotation in OB stars

2020 ◽  
Vol 493 (1) ◽  
pp. 518-535 ◽  
Author(s):  
Z Keszthelyi ◽  
G Meynet ◽  
M E Shultz ◽  
A David-Uraz ◽  
A ud-Doula ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Magnetic Fields ◽  
Massive Star ◽  
Massive Stars ◽  
Rotation Rates ◽  
Momentum Loss ◽  
Star Models ◽  
Surface Rotation ◽  
Angular Momentum Loss ◽  
Magnetic Braking

ABSTRACT The time evolution of angular momentum and surface rotation of massive stars are strongly influenced by fossil magnetic fields via magnetic braking. We present a new module containing a simple, comprehensive implementation of such a field at the surface of a massive star within the Modules for Experiments in Stellar Astrophysics (mesa) software instrument. We test two limiting scenarios for magnetic braking: distributing the angular momentum loss throughout the star in the first case, and restricting the angular momentum loss to a surface reservoir in the second case. We perform a systematic investigation of the rotational evolution using a grid of OB star models with surface magnetic fields (M⋆ = 5–60 M⊙, Ω/Ωcrit = 0.2–1.0, Bp = 1–20 kG). We then employ a representative grid of B-type star models (M⋆ = 5, 10, 15 M⊙, Ω/Ωcrit = 0.2, 0.5, 0.8, Bp = 1, 3, 10, 30 kG) to compare to the results of a recent self-consistent analysis of the sample of known magnetic B-type stars. We infer that magnetic massive stars arrive at the zero-age main sequence (ZAMS) with a range of rotation rates, rather than with one common value. In particular, some stars are required to have close-to-critical rotation at the ZAMS. However, magnetic braking yields surface rotation rates converging to a common low value, making it difficult to infer the initial rotation rates of evolved, slowly rotating stars.

scholarly journals Mass Loss in Algol-Type Stars: Implication on their Evolutionary Stage

1982 ◽  
Vol 69 ◽  
pp. 187-189
Author(s):  
F. Mardirossian ◽  
G. Giuricin
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Mass Loss ◽  
Observational Data ◽  
Mass Exchange ◽  
Total Mass ◽  
Evolutionary Stage ◽  
Momentum Loss ◽  
Evolutionary Scenario ◽  
Angular Momentum Loss

AbstractWe have examined the observational data of 102 Algols in order to clarify the implications on their evolutionary scenario of various assumptions concerning mass and angular momentum loss during mass transfer. We have found that case B mass exchange is strongly favoured for Algols of relatively low total mass (~ M < 7 Mʘ), while case A predominates, though not so widely as expected in Algols of higher total mass.

scholarly journals Mass loss and evolution of hot massive stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 271-281 ◽  
Author(s):  
Jorick S. Vink
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Main Sequence ◽  
Gamma Ray ◽  
Massive Stars ◽  
Gamma Ray Bursts ◽  
Absorption Profile ◽  
Luminous Blue Variables ◽  
Progenitor Stars

AbstractWe discuss the role of mass loss for the evolution of the most massive stars, highlighting the role of the predicted bi-stability jump that might be relevant for the evolution of rotational velocities during or just after the main sequence. This mechanism is also proposed as an explanation for the mass-loss variations seen in the winds from Luminous Blue Variables (LBVs). These might be relevant for the quasi-sinusoidal modulations seen in a number of recent transitional supernovae (SNe), as well as for the double-throughed absorption profile recently discovered in the Hα line of SN 2005gj. Finally, we discuss the role of metallicity via the Z-dependent character of their winds, during both the initial and final (Wolf-Rayet) phases of evolution, with implications for the angular momentum evolution of the progenitor stars of long gamma-ray bursts (GRBs).

scholarly journals Aspects of Mass Loss and Angular Momentum Loss in Binaries Containing Cool Components

1992 ◽  
Vol 151 ◽  
pp. 167-173
Author(s):  
Peter P. Eggleton
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Orbital Angular Momentum ◽  
Cataclysmic Variables ◽  
Close Binary ◽  
Rapid Rotation ◽  
Momentum Loss ◽  
Cool Stars ◽  
Angular Momentum Loss ◽  
Show Evidence

Cool stars show evidence of dynamo activity which is stronger with more rapid rotation. Tidal friction in a moderately close binary can be a cause of relatively rapid rotation, so that cool components in such binaries are presumably liable to stronger stellar winds than single cool stars. As a consequence, the binary can be subject to orbital angular momentum loss. Both the mass loss and the orbital angular momentum loss can be on a timescale comparable to nuclear evolution in a red subgiant, or even faster. RS CVn stars probably give the best possibility of measuring these processes, although some observational data are difficult to reconcile with simple theories.Barium stars, and symbiotics, may both be affected by these processes. They must be the products of evolution of moderately wide binaries, as must such objects as cataclysmic variables. I attempt to define the ranges of zero-age parameters necessary to produce such varied objects. A simplistic model of the distribution of stars brighter than 6th magnitude (a ‘Theoretical Bright Star Catalogue’) suggests that for every three Ba stars with a measurable orbit, there should be one main sequence ‘Ba star’.

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