WISE J064723.23−623235.5 (abbreviated WISE 0647−6232) is a nearby brown dwarf of spectral type Y1 ± 0.5, located in constellation Pictor at approximately 32.5 light-years from Earth.[2] It is one of the two or three reddest and one of the four latest-type brown dwarfs known.[1]
History of observations
Discovery
WISE 0647−6232 was discovered by Kirkpatricket al. from data, collected by Wide-field Infrared Survey Explorer (WISE) Earth-orbiting satellite — NASAinfrared-wavelength 40-cm (16-in) space telescope, which mission lasted from December 2009 to February 2011. The discovery was announced in 2013.
WISE 0647−6232 was first imaged by WISE on 9 May 2010. On 17 June 2010 after preliminary data processing it was uncovered as a very cold brown dwarf candidate.
Then were carried out follow-up observations:
using the Infrared Array Camera (IRAC) on Spitzer Space Telescope, starting from MJD 55458.43 (possibly 16 September 2010);
WISE 0647−6232 became the 17th Y-type dwarf discovered and confirmed spectroscopically (in addition, WD 0806-661B is also almost certainly a Y-type dwarf, which was found before discovery of WISE 0647−6232, but it still lacks a spectroscopical confirmation).[1]
Distance
Currently the most accurate distance estimate of WISE 0647−6232 is a trigonometric parallax, published in 2019 by Kirkpatrick et al.: 10.0+0.2 −0.2pc, or 32.5+0.8 −0.8ly.[2]
WISE 0647−6232 has effective temperature 350–400 K and mass ~5–30MJup, but its kinematics suggests that it may belong to Columba moving group (probability of this is 92.9%, and corresponding radial velocity should be ~22 km/s), if it is so, it may be very young (~30 Myr) and have even lower mass (<2MJup). Its blue J − H color may suggest that its surface gravity may be relatively low (log(g)=3.0–3.5, where g is in units of cm·s−2). For ages from 0.1 to more than 10 Gyr log(g)=4.0–5.0.[1]
The only redder than WISE 0647−6232 confirmed Y dwarf is WISE 1828+2650. WD 0806-661B may also be redder than WISE 0647−6232.