[Normal Stars and WD -- Invited ]
X-ray studies of star and planet formation
Eric Feigelson, Penn State University
Although hardly conceived during the preparation of the
satellite, the Chandra X-ray Observatory is playing a surprisingly
strong role in studies of star and planet formation. Chandra high-resolution
images of active molecular clouds often reveal hundreds of low-mass
young stars, from Class I protostars through Class III disk-free pre-main
sequence stars, as well as massive OB stars. Chandra time series and
spectra provide insights into powerful magnetic flares that are unavailable
at other wavelengths. Though not fully confirmed, the illumination of
protoplanetary disks by high energy output of these flares may play
critical roles in diverse processes of planet formation. Chandra's contributions to several broad themes in star and planet
formation are briefly outlined: history and efficiency of star formation
in molecular clouds; universality of the stellar Initial Mass Function;
triggered star formation on the periphery of HII regions; stellar
environment of OB stars; the large-scale effects of OB winds on molecular
clouds; and the X-ray irradiation of protoplanetary disks.