[Previous] | [Session 9] | [Next]
Nancy Remage Evans, Fredrick D. Seward (SAO)
We have observed the double cluster h and \chi Per with the ROSAT PSPC for 11 ksec. Emission is concentrated toward the two cluster centers, however the resolution at the distance of the clusters (2.4 kpc) is too poor to say whether the emission is diffuse or from a population of unresolved faint sources. 30 sources were found (at the 2.5 \sigma level), with an X-ray luminosity of log L = 31.5 ergs sec-1 or greater. These sources occur in the cluster nuclei, between the clusters and in the halo around the cluster pair. Individual optical sources cannot be identified, but because of the lack of correlation between the X-ray sources and B stars, we conclude that the X-rays are produced by late spectral type pre-main sequence stars. The X-ray sources are brighter than all but the brightest sources in the younger Orion Nebula cluster. These h and \chi sources may represent the peak X-ray flux prior to the main sequence when stars have spun up more than the Orion Nobula stars but have still not fully contracted to the main sequence.
If the author provided an email address or URL for general inquiries,
it is as follows: