Specific Star Forming Regions -- Poster Presentation
XMM-Newton observations of the Upper Scorpius association
Costanza Argiroffi, Dip. di Scienze Fisiche ed Astronomiche, Sezione di Astronomia, Universit\`a di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
F. Favata (1), A. Maggio (2), G. Micela (2), G. Peres (3), & S. Sciortino (2) ((1) Astrophysics Division - Research and Science Support Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands (2) INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy (3) Dip. di Scienze Fisiche ed Astronomiche, Sezione di Astronomia, Universit\`a di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy)
The 5 Myr old Upper Scorpius Association, due to its proximity
(145 pc) and low interstellar absorption, allows a detailed study of the
X-ray emission from PMS stars. We present the results of the analysis of
XMM observations of two Upper Scorpius regions. We detected 224 X-ray
sources among which we identified 21 Upper Scorpius probable members on
the basis of the 2MASS and DENIS photometry. The selected Upper Scorpius
sample includes 7 WTTS, while the nature of the remaining 14 sources it
is not known. Except the high mass star HD 142578 (spectral type A2),
all the other detected Upper Scorpius sources are low mass stars of
spectral type ranging from K to late M. The spectral analysis of the
most intense sources indicates plasma temperature of $\sim10$ MK,
resembling the typical coronal emission of active main sequence stars.
We study the abundance vs. temperature pattern of Upper Scorpius sources
and compare it with that observed for active stars. The Kolmogorov-Smirnov
test proves that 67\% of the detected X-ray Upper Scorpius sources were
variable during the observation, and some of them displayed large
flare-like events.