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Description
This table contains some of the results from a Chandra/ACIS-I observations of the massive ~ 13-14 Myr-old cluster, h Persei, part of the famous Double Cluster (h and Chi Persei) in Perseus. Combining the list of 330 Chandra-detected sources with new optical/IR photometry and optical spectroscopy reveals ~ 165 X-ray bright stars with V <~ 23. Roughly 142 have optical magnitudes and colors consistent with cluster membership. The observed distribution of X-ray luminosity L<sub>x</sub> peaks at L<sub>x</sub> ~ 10<sup>30.3</sup> erg s<sup>-1</sup> and likely traces the bright edge of a far larger population of ~ 0.4-2 M<sub>sun</sub> X-ray active stars. From a short list of X-ray active stars with IRAC 8-micron excess from warm, terrestrial zone dust, the authors derive a maximum X-ray flux incident on forming terrestrial planets. Although there is no correlation between X-ray activity and IRAC excess, the fractional X-ray luminosity correlates with optical colors and spectral type. By comparing the distribution of L<sub>x</sub>/L<sub>star</sub> versus spectral type and (V-I) in h Per with results for other 1-100 Myr-old clusters, the authors show that stars slightly more massive than the Sun (>~ 1.5 M<sub>sun</sub>) fall out of X-ray saturation by ~ 10-15 Myr. Changes in stellar structure for >~ 1.5 M<sub>sun</sub> stars likely play an important role in this decline of X-ray emission. Chandra observations of h Persei were taken with a 41.1 ks exposure on 2004 December 2, (Obs. ID 5407; Sequence Number 200341) with the ACIS detector (chips 0, 1, 2, 3, 6, and 7). The data were obtained in dithered, timed mode, with a frametime of 3.2 s. On-board event rejection and event telemetry was in the VFAINT mode. The field was centered on RA(2000) = 2h19m00s, Dec(2000) = 57d07'12", close to the center of h Persei from Bragg & Kenyon (2005, AJ, 130, 134) (RA(2000) = 2h18m56.4s, Dec(2000) = 57d08'25") and observed at a roll angle of 229 degrees. The data were not registered to an astrometric reference frame (e.g., Two Micron All Sky Survey, 2MASS). The ACIS-I field covers a 17' x 17' area. This table was created by the HEASARC in March 2009 based on the electronic versions of Tables 1 and 2 from the paper which were obtained from the Astronomical Journal web site. This is a service provided by NASA HEASARC .
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