HD 41004

HD 41004 is a star system approximately 139 light years away in the constellation of Pictor.

HD 41004 A

HD 41004 A

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Pictor
Right ascension	5^h 59^m 49.64^s
Declination	−48° 14' 22.89″
Apparent magnitude (V)	8.65
Absolute magnitude (V)	5.51
Distance	138.6 ly (42.5 pc)
Spectral type	K1V
Other designations
HIP 28393, SAO 217660
Database references
SIMBAD	data

HD 41004 A is a primary orange dwarf star of spectral type K1V and apparent magnitude 8.65.

Planetary system

In 2003 a planet HD 41004 Ab was first discovered by Zucker, but not published until 2004. It has a mass >2.56 times that of Jupiter. It orbits at 1.70 astronomical units, taking 963 days, with 74% eccentricity.

The HD 41004 A planetary system

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	>2.56 MJ	1.70	963	0.74	—	—

HD 41004 B

HD 41004 B

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Pictor
Right ascension	5^h 59^m 49.65^s
Declination	−48° 14' 22.90″
Apparent magnitude (V)	12.33
Absolute magnitude (V)	9.16
Distance	140.35 ly (43.03 pc)
Spectral type	M2V
Other designations
n/a
Database references
SIMBAD	data

HD 41004 B is a red dwarf with spectral type M2V and apparent magnitude 12.33.

Brown dwarf

HD 41004 Bb

Discovery
Discovered by	Zucker et al.
Discovery date	2004
Detection method	radial velocity
Orbital characteristics
Semi-major axis	0.0177 AU
Eccentricity	0.081±0.012
Orbital period	1.3283±1.2e-5 d
Average orbital speed	145 km/s
Angular distance	0.411 mas
Longitude of periastron	178.5±7.8°
Time of periastron	2452434.88±0.0029 JD
Semi-amplitude	6114±71 m/s
Physical characteristics
Mass	~16 MJ (most probable)[1] < ~25 MJ[1]

HD 41004 Bb is a brown dwarf that at the time of the discovery was orbiting closer to the star than any known extrasolar planet or brown dwarf (a=0.0177 AU), at only 145 km/s, because of its low-mass parent star, taking 1.3 days. Its orbit is circular despite the gravitational effect of HD 41004 A because of the tidal effect of the nearby star HD 41004 B.^[1]

References

1. Santos, N. C.; Mayor, M.; Naef, D.; Pepe, F.; Queloz, D.; Udry, S.; Burnet, M.; Clausen, J. V.; Helt, B. E.; Olsen, E. H.; Pritchard, J. D. (2002). "The CORALIE survey for southern extra-solar planets. IX. A 1.3-day period brown dwarf disguised as a planet". Astronomy and Astrophysics. 392 (1): 215–229. arXiv:astro-ph/0206213. Bibcode:2002A&A...392..215S. doi:10.1051/0004-6361:20020876.

• Zucker, S.; Mazeh, T.; Santos, N. C.; Udry, S.; Mayor, M. (2004). "Multi-order TODCOR: Application to observations taken with the CORALIE echelle spectrograph. II. A planet in the system HD 41004". Astronomy and Astrophysics. 426 (2): 695–698. Bibcode:2004A&A...426..695Z. doi:10.1051/0004-6361:20040384.

External links

• "HD 41004 A". The Extrasolar Planets Encyclopaedia. Retrieved 2008-07-21.
• "HD 41004 B". The Extrasolar Planets Encyclopaedia. Retrieved 2008-07-21.

Coordinates: 05^h 59^m 49.64^s, −48° 14′ 22.89″