Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 365, Issue 1, Pages L6-L10Publisher
OXFORD UNIV PRESS
DOI: 10.1111/j.1745-3933.2005.00115.x
Keywords
techniques : polarimetric; stars : early-type; stars : individual : HD 191612; stars : magnetic fields; stars : rotation; stars : winds, outflows
Categories
Ask authors/readers for more resources
From observations made with the ESPaDOnS spectropolarimeter, recently installed on the 3.6-m Canada - France - Hawaii Telescope, we report the discovery of a strong magnetic field in the Of? p spectrum variable HD 191612 - only the second known magnetic O star (following theta(1) Ori C). The stability of the observed Zeeman signature over four nights of observation, together with the non-rotational shape of line profiles, argues that the rotation period of HD 191612 is significantly longer than the 9-d value previously proposed. We suggest that the recently identified 538-d spectral variability period is the rotation period, in which case the observed line-of-sight magnetic field of - 220 +/- 38 G implies a large-scale field ( assumed dipolar) with a polar strength of about - 1.5 kG. If confirmed, this scenario suggests that HD 191612 is, essentially, an evolved version of the near-zero-age main-sequence magnetic O star theta(1) Ori C, but with an even stronger field ( about 15 kG at an age similar to that of theta(1) Ori C). We suggest that the rotation rate of HD 191612, which is exceptionally slow by accepted O-star standards, could be due to angular momentum dissipation through a magnetically confined wind.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available