WISEPA J173835.53+273258.9
WISEPA J173835.53+273258.9 is a brown dwarf of spectral class Y0, located in the constellation Hercules at 24.9 light-years from Earth.
History of observations
WISE 1738+2732 was discovered in 2011 from data, collected by the Wide-field Infrared Survey Explorer Earth-orbiting satellite—NASA infrared-wavelength 40 cm space telescope, which mission lasted from December 2009 to February 2011. WISE 1738+2732 has two discovery papers: Kirkpatrick et al. and Cushing et al. , however, basically with the same authors and published nearly simultaneously.- Kirkpatrick et al. presented discovery of 98 new found by WISE brown dwarf systems with components of spectral types M, L, T and Y, among which also was WISE 1738+2732.
- Cushing et al. presented discovery of seven brown dwarfs—one of T9.5 type, and six of Y-type—first members of the Y spectral class, ever discovered and spectroscopically confirmed, including "archetypal member" of the Y spectral class WISE 1828+2650, and WISE 1738+2732. These seven objects are also the faintest seven of 98 brown dwarfs, presented in Kirkpatrick et al. .
Properties
The object's temperature estimate is 350 K. Its spectrum is similar with spectrum of another Y-dwarf WISE 1405+5534.Disequilibrium chemistry models suggest that this Y-dwarf has a low mass of about 3–9, making it a possible isolated planetary-mass object, together with WISE 0350-5658. A more recent paper finds a mass of 5–14.
WISE 1405 is variable in the near- and mid-infrared. The observations were made with the Gemini Observatory and Spitzer. It has a rotation period of 6.0 ± 0.1 hours and the amplitude is 3% for 4.5 μm and may be as high as 5–30% in the near-infrared. This dependence on wavelength can be reproduced with patchy cloud layers made up of potassium chloride and sodium sulfide.