HD 121504

Starbox short
name=HD 121504
epoch=2000
constell=Centaurus
ra=13^h 57^m 17.24^s
dec=-56° 2' 24.53"
spectral=G2V
appmag_v=7.6
dist_ly=144.6
dist_pc=44.57
names=CD-55°5427, HIP 68162

HD 121504 is an 8th magnitude star in the constellation of Centaurus. It is a yellow dwarf (spectral type G2 V) and remarkably similar to our Sun, only slightly brighter like α Centauri A. However, it is located at a distance for about 140 light years and thus is not visible to the unaided eye; binoculars or small telescope is required to see this star.

Another component, designated as SAO 241323 has been proposed as a component of the system. However, the star is an optical binary component and in reality is a white giant star located thousands of light years away.

In 2000 the Geneva Extrasolar Planet Search Team announced the discovery of an extrasolar planet orbiting the star.

HD 121504 b

Infobox Planet
bgcolour = #A0B0FF
name = HD 121504 b
discovery = yes
discovered = 2000
discovery_method = Radial velocity
discoverer = Mayor et al.
semimajor = 0.33 AU
eccentricity = 0.03 ± 0.01
period = 63.33 ± 0.03 d
angular_dist = 7 mas
long_periastron = 265° ± 12°
time_periastron = 2,451,450 ± 2 JD
semi-amplitude = 50.8 ± 0.9 m/s
physical_characteristics = yes
mass = >1.22 "M"_J

The planet, designated as HD 121504 b is likely slightly less massive than Jupiter. The radial velocity method, that was used to detect the planet, can only measure the minimum mass of the planet. Still, it is very unlikely that its true mass would be much higher.

HD 121504 b orbits the star at a distance of about one third Earth's distance from the Sun, and has a slightly eccentric orbit.

References

*cite journal | url=http://www.edpsciences.org/articles/aa/abs/2004/07/aa0250/aa0250.html |author=Mayor et al.|title=The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE |journal = Astronomy and Astrophysics | volume=415 | year=2004 | pages=391–402|doi=10.1051/0004-6361:20034250|format=abstract ( [http://xxx.lanl.gov/abs/astro-ph?papernum=0310316 web Preprint] )

External links

* [http://simbad.u-strasbg.fr/Simbad SIMBAD] [http://simbad.u-strasbg.fr/sim-id.pl?Ident=HD+121504 star entry] , [http://simbad.u-strasbg.fr/sim-id.pl?Ident=HD+121504+B planet entry]
* [http://www.obspm.fr/encycl/encycl.html The Extrasolar Planets Encyclopaedia] [http://www.obspm.fr/encycl/HD121504.html entry]
* [http://www.extrasolar.net/startour.asp?StarID=120 "HD 121504"] at Extrasolar Visions
* [http://www.extrasolar.net/planettour.asp?StarCatId=normal&PlanetId=143 "HD 121504 b"] at Extrasolar Visions