HD 187123

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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
Distance 156.28 ly
(47.92 pc)
Spectral type G5V
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[edit]

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[edit]

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[edit]

References[edit]

  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. ^ a b 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.

External links[edit]

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