The First AllWISE Proper Motion Discovery: WISEA J070720.50+170532.7

March 2014 • 2014AJ....147...61W

Authors • Wright, Edward L. • Kirkpatrick, J. Davy • Gelino, Christopher R. • Fajardo-Acosta, Sergio • Mace, Gregory • Eisenhardt, Peter R. • Stern, Daniel • McLean, Ian S. • Skrutskie, M. F. • Oza, Apurva • Nelson, M. J. • Cushing, Michael C. • Reid, I. Neil • Fumagalli, Michele • Burgasser, Adam J.

Abstract • While quality checking a new motion-aware co-addition of all 12.5 months of Wide-field Infrared Survey Explorer (WISE) data, we found that the source WISE J070720.48+170533.0 moved 0.''9 in six months. Backtracking this motion allowed us to identify this source as 2MASS J07071961+1705464, with several entries in the USNO B catalog. An astrometric fit to these archival data gives a proper motion of μ = 1793 ± 2 mas yr^-1 and a parallax of piv = 35 ± 42 mas. Photometry from WISE, 2MASS, and the POSS can be fit reasonably well by a blackbody with T = 3658 K and an angular radius of 4.36 × 10^-11 radians. No clear evidence of H₂ collision-induced absorption is seen in the near-infrared. An optical spectrum shows broad deep CaH bands at 638 and 690 nm, broad deep Na D at 598.2 nm, and weak or absent TiO, indicating that this source is an ultra-subdwarf M star with a radial velocity v _rad ≈ -21 ± 18 km s^-1 relative to the Sun. Given its apparent magnitude, the distance is about 39 ± 9 pc and the tangential velocity is probably ≈330 km s^-1, but a more precise parallax is needed to be certain.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2014AJ....147...61W
• PDF https://iopscience.iop.org/article/10.1088/0004-6256/147/3/61/pdf
• PREPRINT http://arxiv.org/abs/1310.6717
• DATA https://irsa.ipac.caltech.edu/bibdata/2014/W/2014AJ....147...61W.html
• ELECTR https://iopscience.iop.org/article/10.1088/0004-6256/147/3/61