SIMBAD references

2014ApJS..215...10N - Astrophys. J., Suppl. Ser., 215, 10 (2014/November-0)

X-ray emission from magnetic massive stars.

NAZE Y., PETIT V., RINBRAND M., COHEN D., OWOCKI S., UD-DOULA A. and WADE G.A.

Abstract (from CDS):

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ∼60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower-{dot}M B stars and flattens for the more luminous, higher-{dot}M O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.

Abstract Copyright:

Journal keyword(s): Stars: early-type - Stars: magnetic field - X-rays: stars

Errata: erratum vol. 224, art. 13 (2016)

Simbad objects: 43

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2019.09.23-09:54:24

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