HD 187123

HD 187123
Observation data
Epoch 2000      Equinox 2000
Constellation Cygnus
Right ascension 19h 46m 58.1130s
Declination +34° 25′ 10.288″
Apparent magnitude (V) 7.89
Distance156.28 ly
(47.92 pc)
Spectral typeG5V
Other designations
HD 187123 has a planetary system with at least two planets in it. Artist's rendition of planets HD 187123b and c.

HD 187123 is an 8th magnitude G-type main sequence star located approximately 156 light-years away in the constellation of Cygnus. Like our Sun, it is a yellow dwarf (spectral type G5V). Being at a distance of about 160 light-years it is not visible to the unaided eye. However, it should be easy target with binoculars or small telescope.

Planetary system

In 1998 the California and Carnegie Planet Search team, after following a suggestion by Kevin Apps, a Briton who at the time was an undergraduate student[1] found a possible planet orbiting the star.[2] There were also indications of another, more distant body orbiting the star and this claim was published in 2006.[3] This planet was confirmed in 2009.[4]

The HD 187123 planetary system[4]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥ 0.523 ± 0.043 MJ 0.0426 ± 0.0025 3.0965828 ± 0.0000078 0.0103 ± 0.0059 — —
c ≥ 1.99 ± 0.25 MJ 4.89 ± 0.53 3810 ± 420 0.252 ± 0.033 — —

Sun comparison

This chart compares the sun to HD 117939.

Identifier J2000 Coordinates Distance
(ly)		 Stellar
Class		 Temperature
(K)		 Metallicity
(dex)		 Age
(Gyr)		 Notes
Right ascension Declination
Sun — — 0.00 G2V 5,778 +0.00 4.6 [5]
HD 117939 [6] 13h 34m 32.6s –38° 54′ 26″ 156 G5V 5,730 −0.10 6.1

See also

References

  1. ↑ "British student shows Nasa new planet". BBC News. September 25, 1998. Retrieved December 31, 2011.
  2. ↑ Butler, R. Paul; et al. (1998). "A Planet with a 3.1 Day Period around a Solar Twin". Publications of the Astronomical Society of the Pacific. 110 (754): 1389–1393. Bibcode:1998PASP..110.1389B. doi:10.1086/316287.
  3. ↑ Wright, J. T.; et al. (2007). "Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars". The Astrophysical Journal. 657 (1): 533–545. arXiv:astro-ph/0611658Freely accessible. Bibcode:2007ApJ...657..533W. doi:10.1086/510553.
  4. 1 2 Wright, J. T.; et al. (2009). "Ten New and Updated Multi-planet Systems, and a Survey of Exoplanetary Systems". The Astrophysical Journal. 693 (2): 1084–1099. arXiv:0812.1582Freely accessible. Bibcode:2009ApJ...693.1084W. doi:10.1088/0004-637X/693/2/1084.
  5. ↑ Williams, D.R. (2004). "Sun Fact Sheet". NASA. Retrieved 2009-06-23.
  6. ↑ HD 117939 at SIMBAD - Ids - Bibliography - Image.

Coordinates: 19h 46m 58.1130s, +34° 25′ 10.288″


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