Clustering/Populations -- Poster Presentation
Coronal emission in the youngest stars: a Deep Chandra X-ray
observation of NGC 2362
Francesco Damiani, INAF - Osservatorio Astronomico di Palermo, ITALY
G.Micela (INAF-OAPA, Italy), S.Sciortino (INAF-OAPA, Italy), N.Huelamo (ESO, Chile), F.R.Harnden (SAO), S.S.Murray (SAO)
We present a deep Chandra ACIS-I imaging observation of the
very young cluster NGC 2362. This cluster, only 5 Myr old, is exceptionally
free of dust and differential reddening for its age, and offers a unique
opportunity of studying its pre-main-sequence stellar population with
minimal disturbance from a dense interstellar medium. In this observation
of NGC 2362 we detect almost 400 X-ray sources, most of which identified
optically with low-mass pre-main-sequence stars. The quiescent X-ray
emission of low-mass cluster stars is found to be rather strictly
correlated with the stellar bolometric luminosity, with a spread much
smaller (a factor of 2 rms) than that found in other young clusters.
Such a small spread in the correlation leaves very little room for
variability of the X-ray emission, on timescales of either the stellar
rotation, or longer (e.g., activity cycles). This puts a strong upper
limit on the maximum amplitude of possible activity cycles in very young
coronal sources.