A Search for L/T Transition Dwarfs with Pan-STARRS1 and WISE. III. Young L Dwarf Discoveries and Proper Motion Catalogs in Taurus and Scorpius–Centaurus
- Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
- McDonald Observatory and the University of Texas at Austin, Department of Astronomy, 2515 Speedway C1400, Austin, TX 78712 (United States)
- Lincoln Laboratory, Massachusetts Institute of Technology, 244 Wood Street, Lexington, MA 02420 (United States)
- GMTO Corporation, 251 S. Lake Ave., Suite 300, Pasadena, CA 91101 (United States)
We present the discovery of eight young M7–L2 dwarfs in the Taurus star-forming region and the Scorpius–Centaurus OB Association, serendipitously found during a wide-field search for L/T transition dwarfs using Pan-STARRS1 (optical) and WISE (mid-infrared) photometry. We identify PSO J060.3200+25.9644 (near-infrared spectral type L1) and PSO J077.1033+24.3809 (L2) as new members of Taurus based on their vl-g gravity classifications, the consistency of their photometry and proper motions with previously known Taurus objects, and the low probability of contamination by field objects. PSO J077.1033+24.3809 is the coolest substellar member of Taurus found to date. Both Taurus objects are among the lowest-mass free-floating objects ever discovered, with estimated masses ≈6 M{sub Jup}, and provide further evidence that isolated planetary-mass objects can form as part of normal star formation processes. PSO J060.3200+25.9644 (a.k.a. DANCe J040116.80+255752.2) was previously identified as a likely member of the Pleiades (age ≈ 125 Myr) based on photometry and astrometry, but its vl-g gravity classification and near-infrared photometry imply a much younger age and thus point to Taurus membership. We have also discovered six M7–L1 dwarfs in outlying regions of Scorpius–Centaurus with photometry, proper motions, and low-gravity spectral signatures consistent with membership. These objects have estimated masses ≈15–36 M{sub Jup}. The M7 dwarf, PSO J237.1470−23.1489, shows excess mid-infrared flux implying the presence of a circumstellar disk. Finally, we present catalogs of Pan-STARRS1 proper motions for low-mass members of Taurus and Upper Scorpius with median precisions of ≈3 mas yr{sup −1}, including 67 objects with no previous proper motion and 359 measurements that improve on literature values.
- OSTI ID:
- 22869246
- Journal Information:
- Astrophysical Journal, Vol. 837, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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