Issue |
A&A
Volume 421, Number 2, July II 2004
|
|
---|---|---|
Page(s) | 715 - 727 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20047159 | |
Published online | 22 June 2004 |
XMM-Newton observations of the σ Ori cluster
I. The complex RGS spectrum of the hot star σ Ori AB
INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
Corresponding author: J. Sanz-Forcada, jsanz@rssd.esa.int
Received:
28
January
2004
Accepted:
30
March
2004
We present XMM-Newton observations of the young ( Myr)
cluster around the hot (O9.5V) star σ Orionis AB, aimed at obtaining
a high resolution RGS spectrum of the hot star as well as EPIC imaging data
for the whole field. We show that the RGS spectrum of σ Ori AB may be
contaminated by weaker nearby sources which required the development of a
suitable procedure to extract a clean RGS spectrum and to determine the
thermal structure and wind properties of the hot star. We also report on the
detection of a flare from the B2Vp star σ Ori E and we discuss whether
the flare originated from the hot star itself or rather from an unseen
late-type companion. Other results of this observation include: the
detection of 174 X-ray sources in the field of σ Ori of which 76 are
identified as cluster members, including very low-mass stars down to the
substellar limit; the discovery of rotational modulation in a late-type star
near σ Ori AB; no detectable line broadenings and shifts (
km s-1) in the spectrum of σ Ori AB together with a
remarkable low value of the
forbidden to intercombination line
ratio and unusually high coronal abundances of CNO elements.
Key words: stars: coronae / stars: winds, outflows / stars: individual: σ Ori / stars: early-type / stars: late-type
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.