Notes for star 55 Cnc

From the Extrasolar Planets Encyclopaedia : http://exoplanet.eu

Star : 55 Cnc

THE STAR

- Basic data :

- More data :
	- Basic data (from Simbad) - Most recent ref (from ADS)

Name	55 Cnc
Distance	13.02 (± 0.4) pc	ref.
Spectral Type	G8 V
Apparent Magnitude V	5.95
Mass	1.03 M_sun
Age	5.5 Gyr	ref.
Effective Temperature	5243 (± 93) K	ref.
Radius	1.15 (± 0.035) R_sun	ref.
Metallicity [Fe/H]	0.29
Right Asc. Coord.	08 52 37
Decl. Coord.	+28 20 02

5 PLANETS

- Basic data :

Name	55 Cnc b		55 Cnc c		55 Cnc d		55 Cnc e		55 Cnc f
Discovered in	1996		2002		2002		2004		2007
Mass	0.824 (± 0.007) M_J	ref.	0.169 (± 0.008) M_J	ref.	3.835 (± 0.08) M_J	ref.	0.024 (± 0.0036) M_J	ref.	0.144 (± 0.04) M_J
Semi major axis	0.115 (± 0.0001) AU	ref.	0.24 (± 4.5e-05) AU	ref.	5.77 (± 0.11) AU	ref.	0.038 (± 1e-06) AU	ref.	0.781 (± 0.007) AU
Orbital period	14.65162 (± 0.0007) days	ref.	44.3446 (± 0.007) days	ref.	5218 (± 230) days	ref.	2.81705 (± 0.0001) days	ref.	260 (± 1.1) days
Eccentricity	0.014 (± 0.008)	ref.	0.086 (± 0.052)	ref.	0.025 (± 0.03)	ref.	0.07 (± 0.06)	ref.	0.2 (± 0.2)
ω	131.94 deg.		244.39 (± 11) deg.		181.3 (± 32) deg.	ref.	248.9 (± 38) deg.	ref.	181.1 (± 60) deg.
T_peri	2450002.94749 (± 1.2)	ref.	2449989.3385 (± 3.3)	ref.	2452500.6 (± 230)	ref.	2449999.83643 (± 0.0001)	ref.	2450080.9108 (± 1.1)
Update	07/10/09		07/10/09		07/10/09		24/05/10		07/10/09

- Molecules detected :

Name	55 Cnc b		55 Cnc c		55 Cnc d		55 Cnc e		55 Cnc f
Molecules	None		None		None		None		None

- 55 Cnc Remarks :

24 mar. 05: Planet e challanged; Neptune-sized planet at ~ 0.8 AU? (Wisdom, 2005)
20 apr. 03: Planet in wide (a ~ 1065 AU) binary system (Eggenberger et al 2003)
12 Feb. 03 55 Cnc is one of the 5 targets of the 14 Feb. 03 "Cosmic Call" initiative
13 Jun. 02 Periodicity at 44 d. could be due to stellar rotation, but the planet interpretation is more likely (Marcy et al 2002)
4 Dec. 01:From astrometry with HST (McGrath et al 2002), M < 30 M_J
22 Nov. 00: From astrometry (Han et al. 2000) claim a preliminary mass of 126 M_J and inclination of 179.6^o
Exhibits coherent variations in residual velocities consistent with additional companion.
24 Jul. 00: the source of RV variation remains speculative, depending on completion of one full orbit (Fischer et al 2000).
Possible second companion; see Butler et al. 1996, Jayawardhana et al. 2000.
The star is surrounded by a dust disk extending at least a 40 AU, with an inclination of ~ 25^o. If the planets are in the same plane than the disc, this gives to the first planet a mass of 1.9^+1.1_-0.4 M_J (Trilling & Brown 1998, Trilling et al 2000). But disc not confirmed by Schneider et al (2000b)
There may by a hole with a radius of ~ 10 AU in the disk (Jayawardhana et al 2000)
The star has a companion (rho Cnc B) about 1150 AU away

24 mar. 05: Planet e challanged; Neptune-sized planet at ~ 0.8 AU? (Wisdom, 2005)
20 apr. 03: Planet in wide (a ~ 1065 AU) binary system (Eggenberger et al 2003)
13 Jun. 02 Periodicity at 44 d. could be due to stellar rotation, but the planet interpretation is more likely (Marcy et al 2002)
4 Dec. 01:From astrometry with HST (McGrath et al 2002), M < 30 M_J
22 Nov. 00: From astrometry (Han et al. 2000) claim a preliminary mass of 126 M_J and inclination of 179.6^o
Exhibits coherent variations in residual velocities consistent with additional companion.
24 Jul. 00: the source of RV variation remains speculative, depending on completion of one full orbit (Fischer et al 2000).
Possible second companion; see Butler et al. 1996, Jayawardhana et al. 2000.

30 Mar 2010: Dawson et al. (2010) claim "We find that the period of 2.817 days reported in the literature for planet e (McArthur et al. 2004, Fischer et al. 2008) is actually a daily alias of its true period of 0.737 days. This new period of 0.737 days, with a refined mass of 10 Mearth, produces a significantly improved 5-planet Keplerian fit for 55 Cnc and is the shortest known period for a planet."

- 55 Cnc Other web pages :
	Image of the cirumstellar disk (Trilling & Brown).