HD 80606 b

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HD 80606 b
Exoplanet Comparison HD 80606 b.gif
Computer simulation of weather systems on HD 80606 b, to scale with Jupiter
Discovery [1]
Discovered by Geneva Extrasolar Planet Search
Discovery site Haute-Provence Observatory
Discovery date4 April 2001 [2]
Radial velocity
Orbital characteristics [3]
Apastron 0.8821 AU (131,960,000 km)
Periastron 0.0309 AU (4,620,000 km)
0.4565 ± 0.0053 AU (68,290,000 ± 790,000 km)
Eccentricity 0.93226+0.00064
−0.00069
111.43670±0.00040  d
Average orbital speed
8.8 km/s – 47.3 km/s [notes 1]
Inclination 89.232°±0.029°
2,454,424.857 ± 0.05 [4]
301.03°+0.20°
−0.19°
Semi-amplitude 474.9+2.5
−2.7  m/s
Star HD 80606
Physical characteristics [3]
1.003±0.023  RJ
Mass 4.116+0.097
−0.100  MJ
Mean density
5.06+0.38
−0.35  g/cm3
9.6 g
93+85
−35  h [5]
Temperature <500 - 1400 K [5]

    HD 80606 b (also Struve 1341 Bb or HIP 45982 b) is an eccentric hot Jupiter 217 light-years from the Sun in the constellation of Ursa Major. HD 80606 b was discovered orbiting the star HD 80606 in April 2001 by a team led by Michel Mayor and Didier Queloz. [2] With a mass 4 times that of Jupiter, it is a gas giant. Because the planet transits the host star its radius can be determined using the transit method, and was found to be about the same as Jupiter's. Its density is slightly less than Earth's. [6] It has an extremely eccentric orbit like a comet, with its orbit taking it very close to its star and then back out very far away from it every 111 days. [7]

    Contents

    Discovery

    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 1000 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 4 April 2001. [2] [1]

    The transit was detected using a Celestron 35-cm Schmidt–Cassegrain telescope at the UCL Observatory. [6] Prior to the large data release of the Kepler Mission in February 2011, HD 80606 b had the longest orbital period of any known transiting planet. It takes 12.1 hours to transit its star.

    The transit of 14 January 2010 was partially observed by MOST; but there were equipment failures over part of this time, and the 8 January secondary transit was entirely lost. [8] The midpoint of the next transit was 1 February 2013 11:37 UT. [9]

    Physical properties

    Orbital motion of HD 80606 b. HD80606b Orbit.gif
    Orbital motion of HD 80606 b.
    HD 80606 b – animation (01:28) (28 March 2016).

    HD 80606 b has the most eccentric orbit of any known planet after HD 20782 b. Its eccentricity is 0.9336, comparable to Halley's Comet. 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 interpretation is supported by measurements of the Rossiter–McLaughlin effect, which indicate that the planet's orbit may be significantly inclined (by 42±8°) [10] [11] to the rotational axis of the star, a configuration which would be expected if the Kozai mechanism were responsible for the orbit. [4]

    As a result of this high eccentricity, the planet's distance from its star varies from 0.03 to 0.88 AU. At apastron it would receive an insolation similar to that of Earth, while at periastron the insolation would be around 800 times greater, far more than that experienced by Mercury in the Solar System. In 2009, the eclipse of HD 80606 b by its parent star was detected, allowing measurements of the planet's temperature to be made as the planet passed through periastron. These measurements indicated that the temperature rose from around 800 K (527 °C; 980 °F) to 1,500 K (1,230 °C; 2,240 °F) in just 6 hours. [12]

    An observer above the cloud tops of the gas giant would see the parent star swell to 30 times the apparent size of the Sun in our own sky. [13]

    The planet's rotation period has been measured to be 93+85
    −35     hours, longer than the predicted pseudo-synchronous rotation period of 40 hours. [5]

    Weather

    The planet has wild variations in its weather as it orbits its parent star. Computer models predict the planet heats up 555  K (1,000  °F ) in just a matter of hours, triggering "shock wave storms" that ripple out from the point facing its star, with winds that move at around 5 kilometres per second (3.1 mi/s; 11,000 mph). [12] [14]

    Notes

    1. ↑ From perimeter of the orbit divided by orbital period.

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    References

    1. 1 2 Naef, D.; et al. (August 2001). "HD 80606 b, a planet on an extremely elongated orbit". Astronomy & Astrophysics . 375 (2): L27–L30. arXiv: astro-ph/0106256 . Bibcode:2001A&A...375L..27N. doi:10.1051/0004-6361:20010853. ISSN   0004-6361. S2CID   14433784.
    2. 1 2 3 "Exoplanets: The Hunt Continues!" (Press release). Garching, Germany: European Southern Observatory. 4 April 2001. Retrieved 27 December 2012.
    3. 1 2 Bonomo, A. S.; et al. (June 2017). "The GAPS Programme with HARPS-N at TNG: XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy & Astrophysics . 602: A107. arXiv: 1704.00373 . Bibcode:2017A&A...602A.107B. doi:10.1051/0004-6361/201629882. ISSN   0004-6361. S2CID   118923163.
    4. 1 2 Moutou, C.; et al. (April 2009). "Photometric and spectroscopic detection of the primary transit of the 111-day-period planet HD 80 606 b". Astronomy & Astrophysics . 498 (1): L5–L8. arXiv: 0902.4457 . Bibcode:2009A&A...498L...5M. doi:10.1051/0004-6361/200911954. ISSN   0004-6361. S2CID   14625359.
    5. 1 2 3 de Wit; et al. (April 2016). "Direct Measure of Radiative and Dynamical Properties of an Exoplanet Atmosphere". The Astrophysical Journal Letters . 820 (2): L33. arXiv: 1606.01105 . Bibcode:2016ApJ...820L..33D. doi: 10.3847/2041-8205/820/2/L33 . ISSN   2041-8205.
    6. 1 2 Fossey, Stephen J.; Waldmann, Ingo P.; Kipping, David M. (June 2009). "Detection of a transit by the planetary companion of HD 80606". Monthly Notices of the Royal Astronomical Society . 396 (1): L16–L20. arXiv: 0902.4616 . Bibcode:2009MNRAS.396L..16F. doi: 10.1111/j.1745-3933.2009.00653.x . ISSN   1745-3933. S2CID   2709427.
    7. ↑ "Investigating the Mystery of Migrating 'Hot Jupiters'". Jet Propulsion Laboratory. 28 March 2016. Archived from the original on 24 March 2023.
    8. ↑ Roberts, Jessica E.; et al. (2013). "MOST Space Telescope Photometry of the 2010 January Transit of Extrasolar Planet HD80606b". The Astrophysical Journal . 762 (1): 55. arXiv: 1212.0285 . Bibcode:2013ApJ...762...55R. doi:10.1088/0004-637X/762/1/55. ISSN   0004-637X. S2CID   119251752.
    9. ↑ HD 80606 Transit Times – Variable Star and Exoplanets
    10. ↑ Albrecht, Simon; et al. (30 August 2012). "Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments". The Astrophysical Journal . 757 (1): 18. arXiv: 1206.6105 . Bibcode:2012ApJ...757...18A. doi:10.1088/0004-637X/757/1/18. ISSN   0004-637X. S2CID   17174530.
    11. ↑ Pont, F.; et al. (August 2009). "Spin-orbit misalignment in the HD 80606 planetary system". Astronomy & Astrophysics . 502 (2): 695–703. arXiv: 0906.5605 . Bibcode:2009A&A...502..695P. doi:10.1051/0004-6361/200912463. ISSN   0004-6361. S2CID   55219971.
    12. 1 2 Laughlin, Gregory; et al. (January 2009). "Rapid heating of the atmosphere of an extrasolar planet". Nature . 457 (7229): 562–564. Bibcode:2009Natur.457..562L. doi:10.1038/nature07649. ISSN   0028-0836. PMID   19177124. S2CID   4321053.
    13. ↑ Massey, Robert & Heward, Anita (21 April 2009). "RAS PN 09/23 (NAM 10): London students find Jupiter-sized oddball planet" (Press release). The Royal Astronomical Society. Archived from the original on 16 July 2011. Retrieved 15 July 2009.
    14. ↑ "Exoplanet Sees Extreme Heat Waves". Space.com. 28 January 2009. Archived from the original on 3 June 2009. Retrieved 29 January 2009.

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