HD 80606 and HD 80607 are two stars comprising a binary star system. They are 215 light-years away in the constellation of Ursa Major. Both stars orbit each other at an average distance of 1,200 astronomical units. The binary system is listed as Struve 1341 in the Struve Catalogue of Double Stars; however, this designation is not in wide use and the system is usually referred to by the HD designations of its constituent stars. An extrasolar planet has been confirmed to orbit HD 80606 in a highly elliptical orbit.

Stellar system

The binary system components are very similar G-type main-sequence stars with similar properties to the Sun, although both are older than the Sun and approaching the very end of their main sequence lives.[1][2]

Planetary system

The variable radial velocity of HD 80606 was first noticed in 1999 from observations with the 10 m Keck 1 telescope at the W. M. Keck Observatory in Hawaii by the G-Dwarf Planet Search, a survey of nearly 1,000 nearby G dwarfs to identify extrasolar planet candidates. The star was then followed up by the Geneva Extrasolar Planet Search team using the ELODIE spectrograph mounted on the 1.93 m telescope at the Haute-Provence Observatory. The discovery of HD 80606 b was announced on April 4, 2001.[3][4] Its orbit is misaligned with the star's rotation at 53 degrees.[5][6] Additional studies using the Spitzer Space Telescope in the infrared, and the Very Large Array in the millimeter radio, have shown that the highly eccentric planet 'b' orbiting HD 80606 grazes the parent star at its closest passage to produce difficult-to-detect stellar lobing, severe 'space weather', aurorae and other non-thermal activity.[7][8][9] At the time, its orbit was the most eccentric orbit of any extrasolar planet known.[note 1] It has an eccentricity of 0.9336,[10] comparable to that of Comet Halley in the Solar System. The eccentricity may be a result of the Kozai mechanism, which would occur if the planet's orbit is significantly inclined to that of the binary stars. This conclusion is reinforced by the detection of the misalignment, an expected result of the Kozai mechanism.[5]

In a simulation of a ten-million-year span, the planet "sweeps clean" most test particles within 1.75 AU of HD 80606. The 8:1 resonance hollows out another Kirkwood gap at 1.9 AU. There cannot be any habitable planets in this system. Also, observation has ruled out planets heavier than 0.7 Jupiter masses with a period of one year or less.[11]

See also

References

  1. ^
  2. ^
  3. ^ Naef, D. & Latham, D. W. et al. (2001). "HD 80606 b, a planet on an extremely elongated orbit". Astronomy and Astrophysics Letters. 375 (2): L27–L30. arXiv:astro-ph/0106256. Bibcode:2001A&A...375L..27N. doi:10.1051/0004-6361:20010853. S2CID 14433784
  4. ^ "Exoplanets: The Hunt Continues!". Garching, Germany: European Southern Observatory. April 4, 2001. Retrieved May 2, 2026.
  5. ^ Moutou, C. & Hébrard, G. et al. (2009). "Photometric and spectroscopic detection of the primary transit of the 111-day-period planet HD 80606 b". Astronomy and Astrophysics Letters. 498 (1): L5–L8. arXiv:0902.4457. Bibcode:2009A&A...498L...5M. doi:10.1051/0004-6361/200911954. S2CID 14625359
  6. ^ Roberts, Jessica E. & Barnes, Jason W. et al. (2013). "MOST Space Telescope Photometry of the 2010 January Transit of Extrasolar Planet HD80606b". The Astrophysical Journal. 762 (21): 55. arXiv:1212.0285. Bibcode:2013ApJ...762...55R. doi:10.1088/0004-637X/762/1/55. S2CID 119251752
  7. ^ "Astronomers Observe Planet With Wild Temperature Swings". NASA. 28 January 2009. Archived from the original on 8 March 2016. Retrieved 11 February 2016.
  8. ^ "Spitzer Watches Wild Weather on a Star-Skimming Planet". NASA. 28 January 2009. Retrieved 11 February 2016.
  9. ^ Lazio, T. Joseph W; Shankland, P. D; Farrell, W. M; Blank, D. L (2010). "Radio Observations of Hd 80606 Near Planetary Periastron". The Astronomical Journal. 140 (6): 1929. arXiv:1010.5383. Bibcode:2010AJ....140.1929L. doi:10.1088/0004-6256/140/6/1929. S2CID 35918197
  10. ^ Fossey, S. J. & Waldman, I. P. et al. (2009). "Detection of a transit by the planetary companion of HD 80606". Monthly Notices of the Royal Astronomical Society: Letters. 396 (1): L16–L20. arXiv:0902.4616. Bibcode:2009MNRAS.396L..16F. doi:10.1111/j.1745-3933.2009.00653.x. S2CID 2709427
  11. ^ Wittenmyer, Robert A. & Endl, Michael 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

Notes

  1. ^ Since then, HD 20782 b has been found, with an eccentricity of 0.97.