Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-01-20
Astronomy and Astrophysics
Astrophysics
12 pages, Latex, to appear in The Astrophysical Journal Letters, supplemental material available at http://casa.colorado.edu
Scientific paper
10.1086/310558
We report the discovery of large-amplitude, periodic X-ray emission from the O7 V star theta^1 Orionis C, the central star of the Orion Nebula. Ten ROSAT HRI snapshots of the Trapezium cluster taken over the course of 21 days show that the count rate of theta^1 Ori C varies from 0.26 to 0.41 counts/s with a clear 15-day period. The soft X-ray variations have the same phase and period as H-alpha and He II 4686 variations reported by Stahl et al., and are in anti-phase with the C IV and Si IV ultraviolet absorption features. We consider five mechanisms which might explain the amplitude, phase, and periodicity of the X-ray variations: (1) colliding-wind emission with an unseen binary companion, (2) coronal emission from an unseen late-type pre-main--sequence star, (3) periodic density fluctuations, (4) absorption of magnetospheric X-rays in a corotating wind, and (5) magnetosphere eclipses. The ROSAT data rule out the first three scenarios, but cannot rule out either of the latter two which require the presence of an extended magnetosphere, consistent with the suggestion of Stahl et al. that theta^1 Ori C is an oblique magnetic rotator. As such, theta^1 Ori C may be the best example of a high-mass analog to the chemically peculiar, magnetic Bp stars.
Caillault Jean-Pierre
Gagne Marc
Linsky Jeffrey L.
Stauffer John R.
No associations
LandOfFree
Periodic X-ray Emission from the O7 V Star theta^1 Orionis C 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 Periodic X-ray Emission from the O7 V Star theta^1 Orionis C, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Periodic X-ray Emission from the O7 V Star theta^1 Orionis C will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-423905