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  • 21 Aug, 2019

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TrES-4b
TrES-4b is an extrasolar planet, and one of the largest exoplanets ever found. It was discovered in 2006, and announced in 2007, by the Trans-Atlantic Exoplanet Survey, using the transit method. It is approximately 1,400 light-years (430 pc) away orbiting the star GSC 02620-00648, in the constellation Hercules.

Orbit

A 2008 study concluded that the GSC 06200-00648 system (among others) is a binary star system allowing even more accurate determination of stellar and planetary parameters.

TrES-4 orbits its primary star every 3.543 days and eclipses it when viewed from Earth.

The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to 6.3±4.7°.

Physical characteristics

The planet is slightly less massive than Jupiter (0.919 ± 0.073 MJ) but its diameter is 61% larger. Previously estimated to be 80% larger than Jupiter, it was considered the largest planet ever found at the time, giving it an average density of only about a third of a gram per cubic centimetre, approximately the same as Saturn's moon Methone. This made TrES-4b at the time of its discovery in 2007 both the largest-known planet and the planet with the lowest-known density.

TrES-4b's orbital radius is 0.05091 AU, giving it a predicted surface temperature of about 1,782 K (1,509 °C; 2,748 °F). This by itself is not enough to explain the planet's low density, however. It is not currently known why TrES-4b is so large. The probable causes are the proximity to a parent star that is three to four times more luminous than the Sun as well as the internal heat within the planet.

See also

References

  1. ^ Mandushev, Georgi; et al. (2007). "TrES-4: A Transiting Hot Jupiter of Very Low Density". The Astrophysical Journal Letters. 667 (2): L195 – L198. arXiv:0708.0834. Bibcode:2007ApJ...667L.195M. doi:10.1086/522115. S2CID 6087170.
  2. ^ Daemgen, S.; Hormuth, F.; Brandner, W.; Bergfors, C.; Janson, M.; Hippler, S.; Henning, T. (2009). "Binarity of transit host stars - Implications for planetary parameters" (PDF). Astronomy and Astrophysics. 498 (2): 567–574. arXiv:0902.2179. Bibcode:2009A&A...498..567D. doi:10.1051/0004-6361/200810988. S2CID 9893376.
  3. ^ Johns, Daniel; Marti, Connor; Huff, Madison; McCann, Jacob; Wittenmyer, Robert A.; Horner, Jonathan; Wright, Duncan J. (2018-11-01). "Revised Exoplanet Radii and Habitability Using Gaia Data Release 2". The Astrophysical Journal Supplement Series. 239 (1): 14. arXiv:1808.04533. Bibcode:2018ApJS..239...14J. doi:10.3847/1538-4365/aae5fb. ISSN 0067-0049.
  4. ^ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian B.; Hirano, Teruyuki; Bakos, Gaspar; Hartman, Joel D. (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, S2CID 17174530

Media related to TrES-4 at Wikimedia Commons


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