HD 37605
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Orion
Right ascension 05h 40m 01.7281s[1]
Declination +06° 03′ 38.0743″[1]
Apparent magnitude (V) 8.67[2]
Spectral type K0 V[3]
B−V color index 0.827±0.005[2]
Radial velocity (Rv)−21.81±0.25[1] km/s
Proper motion (μ) RA: 52.466±0.089[1] mas/yr
Dec.: −247.255±0.076[1] mas/yr
Parallax (π)21.3450 ± 0.0517[1] mas
Distance152.8 ± 0.4 ly
(46.8 ± 0.1 pc)
Absolute magnitude (MV)5.46[2]
Mass0.98±0.01 M
Radius0.89±0.01 R
Luminosity0.602±0.002 L
Surface gravity (log g)4.52±0.01 cgs
Temperature5,380±13 K
Metallicity [Fe/H]0.25±0.04[5] dex
Rotation57.67[3] days
Rotational velocity (v sin i)4.5[6] km/s
Age1.8±1.0 or 7[3] Gyr
Other designations
BD+05°985, HD 37605, HIP 26664, SAO 113015, LTT 11695[7]
Database references
Exoplanet Archivedata
Extrasolar Planets

HD 37605 is a star in the equatorial constellation of Orion. It is orange in hue but is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.67.[2] Parallax measurements yield a distance estimate of 153 light years from the Sun. It has a high proper motion[3] and is drifting closer with a radial velocity of −22 km/s.[1]

This object is a K-type main-sequence star with a stellar classification of K0 V.[3] It is an inactive, metal-rich star. Age estimates range from 1.8[4] up to 7[3] billion years old, and it is spinning with a projected rotational velocity of 4.5 km/s.[6] The star has 98% of the mass of the Sun and 89% of the Sun's radius. It is radiating 60% of the luminosity of the Sun from its photosphere at an effective temperature of 5,380 K.[4]


There are two giant planets known in orbit. Planet b was discovered in 2004[8] and planet c was discovered eight years later. The planets do not transit relative to Earth; b's maximum inclination is 88.1%.[3][9]

In a simulation, HD 37605 b's orbit "sweeps clean" most test particles within 0.5 AU; leaving only asteroids "in low-eccentricity orbits near the known planet’s apastron distance, near the 1:2 mean-motion resonance" with oscillating eccentricity up to 0.06, and also at 1:3 with oscillating eccentricity up to 0.4. Also, observation has ruled out planets heavier than 0.7 Jupiter mass with a period of one year or less; which still allows for planets at 0.8 AU or more.[10]

The HD 37605 planetary system[11]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b ≥2.69±0.3 MJ 0.277±0.015 55.01292±0.00062 0.6745±0.0019
c ≥3.19±0.38 MJ 3.74±0.21 2720±15 0.03±0.012


  1. ^ a b c d e f g Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. ^ a b c d e f g Wang Xuesong, Sharon; et al. (2012). "The Discovery of HD 37605c and a Dispositive Null Detection of Transits of HD 37605b". Astrophysical Journal. 761 (1): 46. arXiv:1210.6985. Bibcode:2012ApJ...761...46W. doi:10.1088/0004-637X/761/1/46. S2CID 118679173.
  4. ^ a b c Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
  5. ^ Aguilera-Gómez, Claudia; et al. (2018). "Lithium abundance patterns of late-F stars: An in-depth analysis of the lithium desert". Astronomy and Astrophysics. 614: A55. arXiv:1803.05922. Bibcode:2018A&A...614A..55A. doi:10.1051/0004-6361/201732209. S2CID 62799777.
  6. ^ a b Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 19. arXiv:1611.02897. Bibcode:2017AJ....153...21L. doi:10.3847/1538-3881/153/1/21. S2CID 119511744. 21.
  7. ^ "HD 37605". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-12-31.
  8. ^ Cochran, Michael; et al. (2004). "The First Hobby-Eberly Telescope Planet: A Companion to HD 37605". The Astrophysical Journal Letters. 611 (2): L133–L136. arXiv:astro-ph/0407146. Bibcode:2004ApJ...611L.133C. doi:10.1086/423936.
  9. ^ Kane, S. (2012). "The TERMS Project: More Than Just Transit Exclusion". OASIS. 44 (228.07). Bibcode:2012AAS...21922807K.
  10. ^ Wittenmyer, Robert A.; et al. (2007). "Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary Systems". The Astronomical Journal. 134 (3): 1276–1284. arXiv:0706.1962. Bibcode:2007AJ....134.1276W. doi:10.1086/520880. S2CID 14345035.
  11. ^ Ment, Kristo; et al. (2018). "Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810". The Astronomical Journal. 156 (5). 213. arXiv:1809.01228. Bibcode:2018AJ....156..213M. doi:10.3847/1538-3881/aae1f5. S2CID 119243619.

Coordinates: Sky map 05h 40m 01.7296s, +06° 03′ 38.085″