A Search for Intrinsic Polarization in O Stars with Variable Winds

Details A Search for Intrinsic Polarization in O Stars with Variable Winds A Search for Intrinsic Polarization in O Stars with Variable Winds

1999-09-28

arxiv.org/abs/astro-ph/9909456v1

AJ 119 (2000) 352-364

Astronomy and Astrophysics

Astrophysics

LaTeX2e, 22 pages including 11 tables; 12 separate gif figures; uses aastex.cls preprint package; accepted by The Astronomical

Scientific paper

10.1086/301186

New observations of 9 of the brightest northern O stars have been made with the Breger polarimeter on the 0.9~m telescope at McDonald Observatory and the AnyPol polarimeter on the 0.4~m telescope at Limber Observatory, using the Johnson-Cousins UBVRI broadband filter system. Comparison with earlier measurements shows no clearly defined long-term polarization variability. For all 9 stars the wavelength dependence of the degree of polarization in the optical range can be fit by a normal interstellar polarization law. The polarization position angles are practically constant with wavelength and are consistent with those of neighboring stars. Thus the simplest conclusion is that the polarization of all the program stars is primarily interstellar. The O stars chosen for this study are generally known from ultraviolet and optical spectroscopy to have substantial mass loss rates and variable winds, as well as occasional circumstellar emission. Their lack of intrinsic polarization in comparison with the similar Be stars may be explained by the dominance of radiation as a wind driving force due to higher luminosity, which results in lower density and less rotational flattening in the electron scattering inner envelopes where the polarization is produced. However, time series of polarization measurements taken simultaneously with H-alpha and UV spectroscopy during several coordinated multiwavelength campaigns suggest two cases of possible small-amplitude, periodic short-term polarization variability, and therefore intrinsic polarization, which may be correlated with the more widely recognized spectroscopic variations.

Affiliated with

Also associated with

No associations

Rating

A Search for Intrinsic Polarization in O Stars with Variable Winds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A Search for Intrinsic Polarization in O Stars with Variable Winds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Search for Intrinsic Polarization in O Stars with Variable Winds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-423281