Document 
| Abstract | PDF (384 KB) | PS (351 KB) | References | HTML | Simbad Objects | NASA ADS Abstract Service |
Free access article
A&A 397, 611-621 (2003)
DOI: 10.1051/0004-6361:20021484
Observational clues for a role of circumstellar accretion in PMS X-ray activity
E. Flaccomio, G. Micela and S. SciortinoINAF - Osservatorio Astronomico di Palermo Giuseppe S. Vaiana, Palazzo dei Normanni, 90134 Palermo, Italy
e-mail: giusi@oapa.astropa.unipa.it;sciorti@oapa.astropa.unipa.it
(Received 25 June 2002 / Accepted 9 October 2002)
Abstract
We revisit the published analyses of ROSAT X-ray observations of the star
forming regions NGC 2264 and Chamaeleon I (
3 and
5 Myr old
respectively) in the light of newly published optical data. At odds with
previous results on Chamaeleon I members, we find that low mass stars in both regions have near-saturated emission levels.
Similarly to what previously
found in the Orion Nebula Cluster, Weak Line T-Tauri Stars in NGC 2264 and in
the Chamaeleon I cloud have higher X-ray activity levels respect to Classical T
Tauri Stars, arguing in favor of a role of the disk and/or accretion in
determining X-ray emission.
Key words: stars: pre-main sequence -- X-rays: stars -- accretion, accretion disks -- open clusters and associations: individual: Orion Nebula Cluster, NGC 2264, Chamaeleon I
Offprint request: E. Flaccomio, ettoref@oapa.astropa.unipa.it
SIMBAD Objects
© ESO 2003