SSSPM J1549-3544

SSSPM J1549-3544 is a star in the constellation Lupus with high proper motion. It was initially found to have high proper motion in a 2003 survey of images taken by the optical SuperCOSMOS Sky Surveys and by the near-infrared sky surveys 2MASS and DENIS. It was then thought to be a cool white dwarf close to the Sun.[2] However, more detailed spectroscopic observations in 2005 appear to show that it is not a white dwarf, but a high-velocity halo metal-poor subdwarf.[1]

SSSPM J1549-3544
Observation data
Epoch J2000      Equinox J2000
Constellation Lupus
Right ascension 15h 48m 40.23s[1]
Declination −35° 44′ 25.5″[1]
Apparent magnitude (V) 14.78[1]
Characteristics
Spectral type sdK5[1]
Astrometry
Proper motion (μ) RA: -591[2] mas/yr
Dec.: -538 mas/yr
Absolute magnitude (MV)9.5
Distance ~350 Ly
(~100 parsec)
Details
Temperature< 4500 K
Other designations
SSSPM J1549-3544, 2MASS J15484023-3544254.
Database references
SIMBADdata

References
  1. SSSPM J1549-3544 Is Not a White Dwarf, J. Farihi, P. R. Wood, and B. Stalder, Astrophysical Journal 627, #1 (July 2005), pp. L41–L43.
  2. The nearest cool white dwarf (d ~4 pc), the coolest M-type subdwarf (sdM9.5), and other high proper motion discoveries, R.-D. Scholz, I. Lehmann, I. Matute, and H. Zinnecker, Astronomy and Astrophysics 425 (Oct. 2004), pp. 519–527.
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