X‐Ray and Infrared Observations of Embedded Young Stars in L1630

The HH 24-26 star-forming region within the L1630 dark cloud in Orioncontains a remarkable collection of rare Class 0 and Class I protostars,collimated molecular and ionized jets, and a luminous but spatially unresolvedASCA X-ray source. To study the X-ray properties of the embedded protostarpopulation of that region, we have obtained a deep X-ray image with the ACIS-Scamera on board the Chandra X-Ray Observatory. A number of H-alphaemission-line objects were detected in the areas surrounding HH 24-26, of whichthe weak-line T Tauri star SSV 61 was the brightest source, at a steadyluminosity of 10^31.9 erg/s (0.3-10 keV). Two Class I protostars aligned withoptical jets in HH 24, SSV 63E and SSV 63W, were also detected, as was thecontinuum radio source SSV 63NE, which is very likely an extreme Class I orClass 0 object. We observed no X rays from the Class 0 protostars HH 24-MMS andHH 25-MMS, nor any from regions of the cloud bounded by HH 25 and HH 26, at a2-sigma upper limit of 10^30.0 erg/s. HH 26-IR, the Class I object thought tobe the origin of the HH 26 flow, was not detected. Near-infrared spectroscopyobtained at the NASA IRTF reveals 3 micron ice bands in the spectra of SSV 59,63E, 63W, and HH 26-IR, and 2.3 micron CO overtone absorption bands for SSV 61.SSV 60, which lies astride one end of the great arc of nebulosity forming HH25, exhibits a deep infrared ice band and CO absorption, but is not an X-raysource, and is most likely a distant background giant of late spectral type.