Astronomy:TrES-4b

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TrES-4b
Size comparison of TrES-4 with Jupiter
Discovery
Discovered byMandushev et al[1]
Discovery date2006–2007
Transit
Orbital characteristics
0.05091 ± 0.00071 AU (7.616 ± 0.106 million km)[2]
Eccentricity0
Orbital period3.553945 ± 0.000075 d
Inclination82.86 ± 0.33[2]
Semi-amplitude86.1
StarGSC 02620-00648 A[2]
Physical characteristics
Mean radius1.838+0.240
−0.238 RJ[3]
Mass0.78±0.19 MJ[3]
Mean density0.156+0.072
−0.071 g/cm3[3]
7.04 ± 1.12 m/s2 (23.1 ± 3.7 ft/s2)
0.718 ± 0.114 g
Physics1,782±29 K (1,509 °C; 2,748 °F, equilibrium)[2]


TrES-4b is an exoplanet. It was discovered in 2006, and announced in 2007, by the Trans-Atlantic Exoplanet Survey, using the transit method. At the time of its discovery TrES-4 was the largest confirmed exoplanet ever found, now more than 10 larger planets have been discovered. It is approximately 1,400 light-years (430 pc) away orbiting the star GSC 02620-00648, in the constellation Hercules.[1]

Orbit

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

A 2008 study concluded that the GSC 02620-00648 system (among others) is a binary star system allowing even more accurate determination of stellar and planetary parameters.[2]

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°.[4]

Physical characteristics

The planet is slightly less massive than Jupiter (0.919 ± 0.073 |♃|J}}}}}}) but its diameter is 84% larger. This give TrES-4 an average density of only about a third of a gram per cubic centimetre, approximately the same as Saturn's moon Methone. At the time of its discovery in 2007, TrES-4 was described as both the largest known planet and the planet with the lowest known density.[2][1]

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.[2][1]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 Mandushev, Georgi (2007). "TrES-4: A Transiting Hot Jupiter of Very Low Density". The Astrophysical Journal Letters 667 (2): L195–L198. doi:10.1086/522115. Bibcode: 2007ApJ...667L.195M. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Daemgen, S.; Hormuth, F.; Brandner, W.; Bergfors, C.; Janson, M.; Hippler, S.; Henning, T. (2009). "Binarity of transit host stars - Implications for planetary parameters". Astronomy and Astrophysics 498 (2): 567–574. doi:10.1051/0004-6361/200810988. Bibcode: 2009A&A...498..567D. http://www.mpia.de/homes/henning/Publications/daemgen.pdf. 
  3. ↑ 3.0 3.1 3.2 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. doi:10.3847/1538-4365/aae5fb. ISSN 0067-0049. Bibcode: 2018ApJS..239...14J. 
  4. ↑ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D. et al. (2012). "Obliquities of Hot Jupiter Host Stars: Evidence for Tidal Interactions and Primordial Misalignments". The Astrophysical Journal 757 (1): 18. doi:10.1088/0004-637X/757/1/18. Bibcode: 2012ApJ...757...18A. 

Coordinates: Sky map 17h 53m 13s, +37° 12′ 42″



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