HAT-P-11b

HAT-P-11b
Exoplanet List of exoplanets

Size comparison of HAT-P-11b (gray) with Neptune.
Parent star
Star HAT-P-11
Constellation Cygnus
Right ascension (α) 19h 50m 50.25s[1]
Declination (δ) +48° 04′ 51.1″[1]
Apparent magnitude (mV) 9.59[2]
Distance122 ± 4[1] ly
(37 ± 1[1] pc)
Spectral type K4[2]
Orbital elements
Semi-major axis(a) 0.053+0.0002
−0.0008 AU
Periastron (q) 0.043 AU
Apastron (Q) 0.063 AU
Eccentricity (e) 0.198 ± 0.046
Orbital period(P) 4.8878045±0.0000043[3] d
(0.013381878 ± 0.000000019 y)
Orbital speed (υ) 118 km/s
Inclination (i) 88.5 ± 0.6°
Argument of
periastron		 (ω) 355.2 ± 17.3°
Time of transit (Tt) 2454605.89132 ± 0.00032 JD
Physical characteristics
Mass(m)0.081 ± 0.009 MJ
(26 ± 3 M⊕)
Radius(r)0.422 ± 0.014 RJ
(4.58 ± 0.15 R⊕)
Density(ρ)1440 kg m−3
Surface gravity(g)1.20 g
Discovery information
Discovery date 2 January 2009
Discoverer(s) Bakos et al.
Discovery method Transit (HATNet)
Other detection methods Radial velocity
Discovery site Cambridge, Massachusetts
Discovery status Published
Database references
Extrasolar Planets
Encyclopaedia		data
SIMBADdata
Exoplanet Archivedata
Open Exoplanet Cataloguedata

HAT-P-11b (or Kepler-3b) is an extrasolar planet orbiting the star HAT-P-11. This planet was discovered by the transit method and submitted for publication on 2 January 2009.

This planet is located approximately 122 light-years (37 pc) away[1] in the constellation of Cygnus, orbiting the 10th magnitude K-type star HAT-P-11. This planet was the smallest transiting planet known when first discovered, with a radius about 5 times that of Earth; but is more massive than Gliese 436 b at a true mass of 26 times that of Earth. This planet orbits about the same distance from the star as 51 Pegasi b is from 51 Pegasi, typical of transiting planets. However, the orbit of this planet is eccentric, at around 0.198, unusually high for hot Neptunes. HAT-P-11b's orbit is also highly inclined, with a tilt of approximately 103 degrees relative to its star's rotation.[4][5]

The HAT-P-11 system was within the field of view of the Kepler spacecraft.[2]

Its radial velocity is drifting and this may be a result of an as-yet-undiscovered planet in the system.[2]

The planet fits models for 90% heavy elements. Expected temperature is 878 ± 15K.[2] Actual temperature must await calculations of secondary transit.

On 24 September 2014, NASA reported that HAT-P-11b is the first Neptune-sized exoplanet known to have a relatively cloud-free atmosphere and, as well, the first time molecules, namely water vapor, of any kind have been found on such a relatively small exoplanet.[6]

See also

References

  1. 1 2 3 4 5 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  2. 1 2 3 4 5 Bakos, G. Á.; et al. (2010). "HAT-P-11b: A Super-Neptune Planet Transiting a Bright K Star in the Kepler Field". The Astrophysical Journal 710 (2): 1724–1745. arXiv:0901.0282. Bibcode:2010ApJ...710.1724B. doi:10.1088/0004-637X/710/2/1724.
  3. ↑ Dittmann, Jason A.; Close, Laird M.; Green, Elizabeth M.; Scuderi, Louis J.; Males, Jared R. (2009). "Follow-up Observations of the Neptune Mass Transiting Extrasolar Planet HAT-P-11b". The Astrophysical Journal 699: L48–L51. arXiv:0905.1114v2. Bibcode:2009ApJ...699L..48D. doi:10.1088/0004-637X/699/1/L48.
  4. ↑ "Inclined Orbits Prevail in Exoplanetary Systems". 12 January 2011.
  5. ↑ Roberto Sanchis-Ojeda, Josh N. Winn, Daniel C. Fabrycky (2012). "Starspots and spin-orbit alignment for Kepler cool host stars". arXiv:1211.2002. Bibcode:2013AN....334..180S. doi:10.1002/asna.201211765.
  6. ↑ Clavin, Whitney; Chou, Felicia; Weaver, Donna; Villard; Johnson, Michele (24 September 2014). "NASA Telescopes Find Clear Skies and Water Vapor on Exoplanet". NASA. Retrieved 24 September 2014.

External links

Media related to HAT-P-11b at Wikimedia Commons

Coordinates: 19h 50m 50.2469s, +48° 04′ 51.085″

This article is issued from Wikipedia - version of the Monday, December 29, 2014. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.