HD 40307 e

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HD 40307 e
Exoplanet List of exoplanets
Parent star
Star HD 40307
Constellation Pictor
Right ascension (α) 05h 54m 04.2409s[1]
Declination (δ) −60° 01′ 24.498″[1]
Apparent magnitude (mV) 7.17[1]
Distance 41.8 ± 0.3 ly
(12.83 ± 0.09[1] pc)
Spectral type K2.5V[1]
Radius (r) 0.716 ± 0.010[2] R
Temperature (T) 4977 ± 59[3] K
Metallicity [Fe/H] −0.31 ± 0.03[3]
Age 1.2 (≥ 0.2)[4] Gyr
Orbital elements
Semi-major axis (a) 0.1886 [0.1782, 0.1969][5] AU
Eccentricity (e) 0.06 [0, 0.18][5]
Orbital period (P) 34.62 [34.42, 34.83][5] d
Semi-amplitude (K) 0.84 [0.53, 1.16][5] m/s
Physical characteristics
Minimum mass (m sin i) 3.5 [2.1, 4.9][5] M
Discovery information
Discovery date October 28, 2012
Discoverer(s) Mikko Tuomi et al.
Discovery method radial velocity, using HARPS
Discovery site La Silla Observatory, Chile
Discovery status Announced[5]
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data

HD 40307 e is an extrasolar planet orbiting the star HD 40307. It is located 42 light-years away in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the European Southern Obervatory's HARPS apparatus[5][6][7] by a team of astronomers led by Mikko Tuomi at the University of Hertfordshire and Guillem Anglada-Escude of the University of Goettingen, Germany.[8]

Its minimum mass is 3.5 that of Earth - the smallest - and dynamical models suggest it cannot be much more (and so is measured close to edge-on).[5] It further gets roughly the same insolation from its star as Mercury gets from the Sun.[9] Planets like this in that system have been presumed "super-Earth".[3]

However planets b, c, and d are presumed to have migrated in from outer orbits; and planet b is predicted a sub-Neptune.[10] It is likely that this planet formed even further out. Whether it is a sub-Neptune, a super-Venus or even a super-Mercury is unknown.


  1. ^ a b c d e "HD 40307". SIMBAD. Centre de Données astronomiques de Strasbourg. 2008. Retrieved 18 June 2008. 
  2. ^ HD 40307, entry, CDS database J/A+A/450/735; described in Effective temperature scale and bolometric corrections from 2MASS photometry, E. Masana, C. Jordi, and I. Ribas, Astronomy and Astrophysics 450, #2 (May 2006), pp. 735–746. Bibcode2006A&A...450..735M. doi:10.1051/0004-6361:20054021.
  3. ^ a b c M. Mayor; S. Udry; C. Lovis; F. Pepe; D. Queloz; W. Benz; J.-L. Bertaux; F. Bouchy; C. Mordasini; D. Segransan (2009). "The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)". Astronomy and Astrophysics. 493 (2): 639–644. arXiv:0806.4587Freely accessible. Bibcode:2009A&A...493..639M. doi:10.1051/0004-6361:200810451. 
  4. ^ HD 40307, database entry, Geneva-Copenhagen Survey of Solar neighbourhood, J. Holmberg et al., 2007, CDS database V/117A, accessed November 19, 2008; described in The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ~14 000 F and G dwarfs, B. Nordström, M. Mayor, J. Andersen, J. Holmberg, F. Pont, B. R. Jørgensen, E. H. Olsen, S. Udry, and N. Mowlavi, Astronomy and Astrophysics 418 (May 2004), pp. 989–1019, Bibcode2004A&A...418..989N, doi:10.1051/0004-6361:20035959.
  5. ^ a b c d e f g h Tuomi, Mikko; Anglada-Escude, Guillem; Gerlach, Enrico; Jones, Hugh R. R.; Reiners, Ansgar; Rivera, Eugenio J.; Vogt, Steven S.; Butler, R. Paul (2012). "Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307". Astronomy. 549: A48. arXiv:1211.1617v1Freely accessible [astro-ph]. Bibcode:2013A&A...549A..48T. doi:10.1051/0004-6361/201220268. 
  6. ^ Wall, Mike (November 7, 2012). "'Super-Earth' Alien Planet May Be Habitable for Life". Space.com. Retrieved November 8, 2012. 
  7. ^ Tate, Karl (November 7, 2012). "Super-Earth Planet: Potentially Habitable Alien World Explained (Infographic)". Space.com. Retrieved November 8, 2012. 
  8. ^ Murrin, Marc (November 8, 2012). "Astronomers discover a potentially habitable Super-Earth HD 40307g (Infographic)". tech-stew.com. Retrieved November 8, 2012. 
  9. ^ Tuomi, Fig. 17
  10. ^ Barnes, R.; Jackson, B.; Raymond, S.; West, A.; Greenberg, R. (2009). "The HD 40307 Planetary System: Super-Earths or Mini-Neptunes?". The Astrophysical Journal. 695 (2): 1006. arXiv:0901.1698Freely accessible. Bibcode:2009ApJ...695.1006B. doi:10.1088/0004-637X/695/2/1006. 

External links[edit]

Coordinates: Sky map 05h 54m 04.2409s, −60° 01′ 24.498″