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YBP 1194 is a G-type main-sequence star, class G5V, in the open cluster M67 in the constellation Cancer.[6][7] It is the best solar twin found to date, having the near temperature and mass as our sun. YBP 1194 has a higher metallicity than the Sun. YBP 1194 is .5 billion years younger than the Sun at an age of 4.2 billion years old, but due to the distance, the error bar is high at ±1.6 billion years. On December 19, 2013, it was announced to have an extrasolar planet with a period of 6.9 days, and a high eccentricity of 0.24 with a mass of 0.34 MJ.[7] YBP 1194 is about 2,772 light-years (850 parsecs) from the Sun.[3][8] YBP 1194 is packed in a small cluster, M67-NGC 2682, with a radius 10 ly, with over 500 other stars.[9] For comparison the Sun has 17 stars at a distance of 10 ly and about 134 stars at a distance of 20 ly.[10][11]

YBP 1194
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cancer
Right ascension  08h 51m 00.807s[1]
Declination +11° 48′ 52.76″[1]
Apparent magnitude (V) 14.676[2]
Spectral type G5V[3]
B−V color index 0.626[3]
Radial velocity (Rv)+36.5 ± 0.9[4] km/s
Proper motion (μ) RA: -7.3[2] mas/yr
Dec.: -4.3[2] mas/yr
Mass1.01 ± 0.02[3] M
Radius0.99 ± 0.02[3] R
Surface gravity (log g)4.44 ± 0.035[3] cgs
Temperature5780 ± 27[3] K
Metallicity0.023 ± 0.015[3]
Age4.2 ± 1.6[5] Gyr
Other designations
NGC 2682 YBP 1194, ES 4063, ES IV-63, FBC 2867, MMJ 5357, SAND 770, 2MASS J08510080+1148527
Database references


Exoplanet YBP 1194 b was discovered in January 2014 by researchers at the European Southern Observatory (ESO) when three new planets were discovered in the M67 cluster, one of them orbiting YPB 1194, showing that open star clusters are more likely to have planets orbiting them than originally thought. The exoplanet is prominently about 100 times the mass of Earth. Exoplanet YBP 1194 b when compared to the Sun-Earth, orbits the star about 87 million miles closer than planet Mercury. The orbital eccentricity of YPB 1194 b is 0.24, close to Pluto's eccentricity of 0.24905.[7][12] The composition of these planets is currently, unknown.[7][13]

The YBP 1194 planetary system
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 0.34 MJ 0.0716 6.9 0.24


  1. ^ a b Cutri, R. M. (2003). "2MASS All-Sky Catalog of Point Sources". VizieR On-line Data Catalog. 2246. Bibcode:2003yCat.2246....0C.
  2. ^ a b c Krone-Martins, A.; Soubiran, C.; Ducourant, C.; Teixeira, R.; Le Campion, J. F. (2010). "Kinematic parameters and membership probabilities of open clusters in the Bordeaux PM2000 catalogue". Astronomy and Astrophysics. 516: A3. arXiv:1006.0096. Bibcode:2010A&A...516A...3K. doi:10.1051/0004-6361/200913881.
  3. ^ a b c d e f g h Brucalassi, A.; Pasquini, L.; Saglia, R.; et al. (2014). "Three planetary companions around M 67 stars". Astronomy & Astrophysics. 561: L9. arXiv:1401.4905. Bibcode:2014A&A...561L...9B. doi:10.1051/0004-6361/201322584.
  4. ^ Lee, Young Sun; Beers, Timothy C.; Sivarani, Thirupathi; Johnson, Jennifer A.; An, Deokkeun; Wilhelm, Ronald; Allende Prieto, Carlos; Koesterke, Lars; Fiorentin, Paola Re; Bailer-Jones, Coryn A. L.; Norris, John E.; Yanny, Brian; Rockosi, Constance; Newberg, Heidi J.; Cudworth, Kyle M.; Pan, Kaike (2008). "The Segue Stellar Parameter Pipeline. Ii. Validation with Galactic Globular and Open Clusters". The Astronomical Journal. 136 (5): 2050. arXiv:0710.5778. Bibcode:2008AJ....136.2050L. doi:10.1088/0004-6256/136/5/2050.
  5. ^ "Confirmed Exoplanet Overview". exoplanetarchive. Retrieved 4 March 2016.
  6. ^ "Cl* NGC 2682 YBP 1194". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 March 2014.
  7. ^ a b c d David Dickinson (January 15, 2014). "New exoplanet discoveries in open star cluster". Postmedia News. Retrieved March 4, 2014.
  8. ^ Department of Physics and Astronomy, Division of AstronomyUppsala University, M67-1194, an unusually Sun-like solar twin in M67, by A. Önehag1, A. Korn1, B. Gustafsson1, E. Stempels1 and D. A. VandenBerg2, April 2011
  9. ^ M67 Cluster
  10. ^ Sol Station Company, Stars Stars within 10 light-years
  11. ^ Sol Station Company, Stars Stars within 20 light-years
  12. ^ "Rare Planet Discovered Orbiting Twin of Earth's Sun in Star Cluster". January 15, 2014. Retrieved March 4, 2014.
  13. ^, M 67 YBP 1194 b