Rho Coronae Borealis

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**Rho CrB**
Observation data Epoch J2000
Rho Coronae Borealis
Constellation (pronunciation)	Aquila
Right ascension	16h 01m 02.6616s
Declination	+33° 18' 12.634"'
Apparent magnitude (V)	5.4
Characteristics
Spectral type	G0Va
U-B color index	?
B-V color index	?
Variable type	None
Astrometry
Radial velocity (R_v)	18.4 km/s
Proper motion (μ)	RA: -196.88 mas/yr Dec.: -773.00 mas/yr
Parallax (π)	57.38 ± 0.71 mas
Distance	56.8 ± 0.7 ly (17.4 ± 0.2 pc)
Absolute magnitude (M_V)	6.04
Details
Mass	0.95 M_☉
Radius	67.5 R_☉
Luminosity	1.8 L_☉
Temperature	? K
Metallicity	?
Rotation	?
Age	6 billion years
Other designations
LHS 3145, 1E 1559.1+3327, IDS 15573+3337 A, SAO 65024, * 15 CrB, GC 21527, GCRV 9214, LFT 1241, SPOCS 682, AG+33° 1399, LSPM J1601+3318, TD1 18787, ASCC 593934, GJ 9537, LTT 14764, TYC 2576-2228-1, BD+33° 2663, GJ 606.2, 2MASS J16010264+3318124, BDS 7480 A, HD 143761, NLTT 41765, UBV 13592, CCDM J16011+3318A, HIC 78459, PLX 3626, USNO-B1.0 1233-00263888, Ci 20 959, HIP 78459, PPM 78975, CSI+33 2663 1, HR 5968, ROT 2268.
Database references
SIMBAD	data

Rho Coronae Borealis (ρ CrB / ρ Coronae Borealis) is a 5th magnitude star in the constellation of Corona Borealis. It is, like our Sun, a yellow dwarf (spectral type G0 V or G2 V) and only slightly brighter. It may be much older than the Sun, 10,000 million years old.

In 1997 the AFOE planet search team announced the discovery of an extrasolar planet orbiting the star. Furthermore, in 1997 the star was observed radiating excessively in certain infrared wavelengths indicating a circumstellar disk around the star, similar to the Kuiper belt in our Solar system.

A stellar companion has been listed for ρ Coronae Borealis in the Washington Visual Double Star Catalog, but no further information is available on it. It may be just a line-of-sight optical companion.

1 ρ Coronae Borealis b
2 See also
3 References
4 External links

[edit] ρ Coronae Borealis b

**ρ Coronae Borealis b**
Discovery
Discovered by	Noyes et al.
Discovery date	April 24, 1997
Detection method	Radial velocity
Orbital characteristics
Semi-major axis	0.229 ± 0.013 AU
Eccentricity	0.057 ± 0.028
Orbital period	39.8449 ± 0.0063 d
Angular distance	13.773 mas
Longitude of periastron	303°
Time of periastron	2,450,563.2 ± 4.1 JD
Semi-amplitude	64.9 ± 2.4 m/s
Physical characteristics
Mass	>1.093 ± 0.098 M_J

The planet, one of the first discovered (discovered on April 24, 1997), is designated as ρ Coronae Borealis b. The planet's distance to the star is only about one fifth Earth's distance from the Sun. The orbit is circular and it takes 40 days to complete one revolution around the star. The planet has a mass about that of Jupiter. However, the inclination of the orbital plane is not known, so the value is only a minimum. If the planet orbits in the same plane as the circumstellar disk, the inclination would be about 46° and mass of the planet 1.5 times Jupiter.

In 2000 group of scientist claimed, based on preliminary Hipparcos astrometrical satellite data, that the inclination of the planet would be 0.5° and mass as much as 115 times Jupiter. Such a massive body would be nothing else but a dim red dwarf. However, this is statistically very unprobable, and the claim has not been backed up.