BD+20°2457 b

BD+20°2457 b

Extrasolar planet		List of extrasolar planets
Artistic rendering of BD+20 2457 b
Parent star
Star		BD+20°2457
Constellation		Leo
Right ascension	(α)	10h 16m 44.8635s
Declination	(δ)	+19° 53′ 28.974″
Distance		650 ± 330 ly (200 ± 100 pc)
Spectral type		K2II
Orbital elements
Semimajor axis	(a)	1.45 AU
Periastron	(q)	1.23 AU
Apastron	(Q)	1.67 AU
Eccentricity	(e)	0.15 ± 0.03
Orbital period	(P)	379.63 ± 2.01 d (1.0394 ± 0.0055 y)
Argument of periastron	(ω)	207.64 ± 21.99°
Time of periastron	(T0)	54677.03 ± 28.19 JD
Semi-amplitude	(K)	? m/s
Physical characteristics
Minimum mass	(m sin i)	21.42 MJ
Discovery information
Discovery date		June 10, 2009
Discoverer(s)		Niedzielski et al.
Detection method		radial velocity
Discovery site		La Silla Observatory
Discovery status		Published
Database references
Extrasolar Planets Encyclopaedia		data
SIMBAD		data

BD+20°2457 b is a brown dwarf located between 320 to 980 light years away in the constellation of Leo, orbiting the 10th magnitude K-type bright giant star BD+20°2457. It has mass 21.42 times more massive than Jupiter and the orbit takes 4% longer than Earth’s to go around the star. The other companion in this system BD+20°2457 c, is a very massive planet (massing at least 12.47 times greater than Jupiter), meaning it is likely that the other companion may also be a brown dwarf. This brown dwarf was discovered on June 10, 2009, using the Hobby-Eberly Telescope.

See also

• BD+14°4559 b
• HD 240210 b

References

• Niedzielski et al. (2009). "Substellar-mass Companions to the K-dwarf BD+14 4559 and the K-giants HD 240210 and BD+20 2457" (abstract). The Astrophysical Journal 707 (1): 768–777. Bibcode 2009ApJ...707..768N. doi:10.1088/0004-637X/707/1/768. http://www.iop.org/EJ/abstract/0004-637X/707/1/768.  (web preprint)