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

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.

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832581 ◽

2019 ◽

Vol 625 ◽

pp. A89 ◽

Cited By ~ 5

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.

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Mass-loss predictions and stellar masses of early-type stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900211832 ◽

2003 ◽

Vol 212 ◽

pp. 164-165 ◽

Cited By ~ 1

Author(s):

Alex de Koter ◽

Jorick S. Vink

Keyword(s):

Mass Loss ◽

Massive Stars ◽

Spectroscopic Binaries ◽

Evolution Theory ◽

Early Type ◽

Direct Measurements ◽

Wind Theory ◽

Early Type Stars ◽

Stellar Masses

We show that the stellar masses implied by our predictions of the wind properties of massive stars are in agreement with masses derived from evolution theory and from direct measurements using spectroscopic binaries, contrary to previous attempts to derive masses from wind theory.

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The Metallicity Dependence of the Mass Loss of Early-Type Massive Stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308020322 ◽

2007 ◽

Vol 3 (S250) ◽

pp. 39-46

Author(s):

Alex de Koter

Keyword(s):

Mass Loss ◽

Metal Content ◽

Massive Stars ◽

Magellanic Clouds ◽

Stellar Winds ◽

Early Type ◽

The Galaxy ◽

Early Type Stars ◽

Good Agreement ◽

Comprehensive Study

AbstractWe report on a comprehensive study of the wind properties of 115 O- and early B-type stars in the Galaxy and the Large Magellanic Clouds. This work is part of the VLT/FLAMES Survey of Massive Stars. The data is used to construct the empirical dependence of the mass-loss in stellar winds on the metal content of their atmospheres. The metal content of early-type stars in the Magellanic Clouds is discussed. Assuming a power-law dependence of mass loss on metal content, Ṁ ∝ Zm, we find m = 0.83 ± 0.16 from an analysis of the wind momentum luminosity relation (Mokiem et al. 2007b). This result is in good agreement with the prediction m = 0.69 ± 0.10 by Vink et al. (2001). Though the scaling agrees, the absolute empirical value of mass loss is found to be a factor of two higher than predictions. This may be explained by a modest amount of clumping in the outflows of the objects studied.

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Observational Properties of Nonradial Oscillations in Early-Type Stars and their Possible Effect on Mass Loss: the Example of ζ Puppis (04 If)

Seismology of the Sun and the Distant Stars ◽

10.1007/978-94-009-4608-8_48 ◽

1986 ◽

pp. 465-466 ◽

Cited By ~ 11

Author(s):

Dietrich Baade

Keyword(s):

Mass Loss ◽

Early Type ◽

Early Type Stars ◽

Nonradial Oscillations

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Terminal Velocities for a Large Sample of O Stars, B Supergiants, and Wolf-Rayet Stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900045381 ◽

1991 ◽

Vol 143 ◽

pp. 317-317

Author(s):

R. K. Prinja ◽

M. J. Barlow ◽

I. D. Howarth

Keyword(s):

High Resolution ◽

Mass Loss ◽

Early Type ◽

Nuclear Mass ◽

Ob Stars ◽

Residual Intensity ◽

The Mean ◽

Effective Temperatures ◽

Early Type Stars ◽

Absorption Features

We argue that easily measured, reliable estimates of terminal velocities for early-type stars are provided (1) by the central velocity asymptotically approached by narrow absorption features in unsaturated UV P Cygni profiles, and (2) by the violet limit of zero residual intensity in saturated P Cygni profiles. We use these estimators and high resolution IUE data to determine terminal velocities, v∞, for 181 O stars, 70 early B supergiants, and 35 Wolf-Rayet stars. For OB stars our values are typically 15-20% smaller than the extreme violet edge velocities, vedge, while for WR stars v∞ = 0.76vedge on average. We give new mass-loss rates for WR stars which are thermal radio emitters, taking into account our new terminal velocities and recent revisions to estimates of distances and to the mean nuclear mass per electron. We examine the relationships between v∞, the surface escape velocities, and effective temperatures.

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Mass loss from early-type stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900102074 ◽

1970 ◽

Vol 36 ◽

pp. 209-212

Author(s):

J. B. Hutchings

Keyword(s):

Mass Loss ◽

Spectral Type ◽

Stellar Evolution ◽

Early Type ◽

High Luminosity ◽

Spectroscopic Evidence ◽

Ob Stars ◽

Early Type Stars ◽

Very High ◽

Hr Diagram

Following the detailed study of four very high luminosity OB stars, a survey has been made for spectroscopic evidence of mass loss in a number of early-type supergiants. A list of spectroscopic criteria is given and the mass loss estimates for 24 stars plotted on the HR diagram. The dependence of the phenomenon on spectral type and luminosity is discussed as well as its significance in terms of stellar evolution.

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VLA radio continuum measurements of mass loss from early-type stars

The Astrophysical Journal ◽

10.1086/157973 ◽

1980 ◽

Vol 238 ◽

pp. 196 ◽

Cited By ~ 63

Author(s):

D. C. Abbott ◽

J. H. Bieging ◽

E. Churchwell ◽

J. P. Cassinelli

Keyword(s):

Mass Loss ◽

Radio Continuum ◽

Early Type ◽

Early Type Stars

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Mass-loss rates in early-type stars determined by fitting Balmer alpha profiles

The Astrophysical Journal ◽

10.1086/159231 ◽

1981 ◽

Vol 248 ◽

pp. 1021 ◽

Cited By ~ 12

Author(s):

G. L. Olson ◽

D. Ebbets

Keyword(s):

Mass Loss ◽

Early Type ◽

Early Type Stars ◽

Loss Rates

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Mass Loss and Stellar Wind in Massive X-Ray Binaries

Highlights of Astronomy ◽

10.1017/s1539299600004433 ◽

1980 ◽

Vol 5 ◽

pp. 541-547

Author(s):

H. F. Henrichs

Keyword(s):

Mass Loss ◽

Stellar Wind ◽

Binary Systems ◽

Massive Stars ◽

Compact Star ◽

X Rays ◽

Early Type ◽

X Ray ◽

X Ray Binaries ◽

Loss Rates

A number of massive stars of early type is found in X-ray binary systems. The catalog of Bradt et al. (1979) contains 21 sources optically identified with massive stars ranging in spectral type from 06 to B5 out of which 13 are (nearly) unevolved stars and 8 are supergiants. Single stars of this type generally show moderate to strong stellar winds. The X-rays in these binaries originate from accretion onto a compact companion (we restrict the discussion to this type of X-rays).We consider the compact star as a probe traveling through the stellar wind. This probe enables us to derive useful information about the mass outflow of massive stars.After presenting the basic data we derive an upper limit to mass loss rates of unevolved early type stars by studying X-ray pulsars. Next we consider theoretical predictions concerning the influence of X-rays on the stellar wind and compare these with the observations. Finally, using new data from IUE, we draw some conclusions about mass loss rates and velocity laws as derived from X-ray binaries.

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