HD 17156 b

HD 17156 b / Mulchatna
Size comparison of HD 17156 b with Jupiter.
Discovery
Discovered byFischer et al.[1]
Discovery siteW. M. Keck Observatory
Subaru Telescope
Discovery date14 April 2007
Radial velocity and Transit
Orbital characteristics
0.1589 AU (23,770,000 km)[2]
Eccentricity0.6768 ± 0.0034[3]
21.2163979 ± 0.0000159[3] d
Inclination86.573 ± 0.060[3]
2454438.4835±0.0025[2]
121.71 ± 0.43[3]
Semi-amplitude274.2 ± 2.0[3]
StarHD 17156
Physical characteristics
1.0870 ± 0.0066[3] RJ
Mass3.191 ± 0.033[3] MJ
Mean density
3.47 g/cm3[2]
67.0 ± 2.4 m/s2 (219.8 ± 7.9 ft/s2)[3]
Temperature?

HD 17156 b, named Mulchatna by the IAU,[4] is an extrasolar planet approximately 255 light-years away in the constellation of Cassiopeia. The planet was discovered orbiting the yellow subgiant star HD 17156 in April 2007. The planet is classified as a relatively cool hot Jupiter planet slightly smaller than Jupiter but slightly larger than Saturn. This highly-eccentric three-week orbit takes it approximately 0.0523 AU of the star at periastron before swinging out to approximately 0.2665 AU at apastron. Its eccentricity is about the same as 16 Cygni Bb, a so-called "eccentric Jupiter". Until 2009, HD 17156 b was the transiting planet with the longest orbital period.[5]

  1. ^ Cite error: The named reference Fischer2007 was invoked but never defined (see the help page).
  2. ^ a b c Gillon, M.; Triaud, A. H. M. J.; Mayor, M.; Queloz, D.; Udry, S.; North, P. (2007). "Improved parameters for the transiting planet HD 17156b: A high-density giant planet with a very eccentric orbit". Astronomy and Astrophysics. 485 (3): 871–875. arXiv:0712.2073. Bibcode:2008A&A...485..871G. doi:10.1051/0004-6361:20079238. S2CID 14564072.
  3. ^ a b c d e f g h Cite error: The named reference Nutzman2011 was invoked but never defined (see the help page).
  4. ^ "Approved names (§ United States of America)". Name Exo Worlds. IAU. Retrieved 19 December 2019.
  5. ^ TransitSearch (See: HD 80606 b)