Ten Micron Observations of Nearby Young Stars

(abridged) We present new 10-micron photometry of 21 nearby young starsobtained at the Palomar 5-meter and at the Keck I 10-meter telescopes as partof a program to search for dust in the habitable zone of young stars. Thirteenof the stars are in the F-K spectral type range ("solar analogs"), 4 have B orA spectral types, and 4 have spectral type M. We confirm existing IRAS12-micron and ground-based 10-micron photometry for 10 of the stars, andpresent new insight into this spectral regime for the rest. Excess emission at10 micron is not found in any of the young solar analogs, except for a possible2.4-sigma detection in the G5V star HD 88638. The G2V star HD 107146, whichdoes not display a 10-micron excess, is identified as a new Vega-likecandidate, based on our 10-micron photospheric detection, combined withpreviously unidentified 60-micron and 100-micron IRAS excesses. Among theearly-type stars, a 10-micron excess is detected only in HD 109573A (HR 4796A),confirming prior observations; among the M dwarfs, excesses are confirmed in AATau, CD -40 8434, and Hen 3-600A. A previously suggested N band excess in theM3 dwarf CD -33 7795 is shown to be consistent with photospheric emission.Comment: 40 pages, 4 figures, 5 tables. To appear in the January 1, 2004 issue of Ap