HAT-P-11b

Coordinates: Sky map 19h 50m 50.2469s, +48° 04′ 51.085″
Source: Wikipedia, the free encyclopedia.

Periastron
0.0413+0.0018
−0.0019 AU
0.05254+0.00064
−0.00066 AU
Eccentricity0.218+0.034
−0.031[2]
4.887802443+0.000000034
−0.000000030[3] d
Inclination89.05+0.15
−0.09[3]
2454957.15+0.17
−0.20[2]
19+14
−16[2]
Semi-amplitude10.42+0.64
−0.66[2]
StarHAT-P-11
Physical characteristics
Mean radius
4.36±0.06[3] R🜨
Mass23.4±1.5[2] ME
Mean density
1,440 kg/m3 (2,430 lb/cu yd)
1.20 g

HAT-P-11b (or

transit method
, and submitted for publication on 2 January 2009.

This planet is located approximately 123 light-years (38 pc) distant from Earth.[4]

Discovery

The HATNet Project team initially detected the

transits of HAT-P-11b from analysis of 11470 images, taken in 2004 and 2005, by the HAT-6 and HAT-9 telescopes. The planet was confirmed using 50 radial velocity measurements taken with the HIRES radial velocity spectrometer at W. M. Keck Observatory.[1]

At the time of its discovery HAT-P-11b was the smallest radius transiting extrasolar planet discovered by a ground based transit search and was also one of three previously known transiting planets within the initial

Kepler spacecraft.[1]

There was a linear trend in the radial velocities indicating the possibility of another planet in the system.[1] This planet, HAT-P-11c, was confirmed in 2018.[2]

Characteristics

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 103+26
−10°.[5] degrees relative to its star's rotation.[6][7] The planet is probably composed primarily of heavy elements with only 10% hydrogen and helium by mass, like Gliese 436 b.[1]

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.[8]

In 2009 French astronomers observed what was thought to be a weak unpolarized radio signal coming from the exoplanet, but it was not observed in a repeat observation in 2010.[9] If the signal was real, then it was probably due to intense lightning storms with similar properties as ones on Saturn.[10]

In December 2021 evidence of a magnetosphere was discovered in HAT-P-11b that could be the first ever in any exoplanet.[11][12][13]

See also

References

  1. ^
    doi:10.1088/0004-637X/710/2/1724
    .
  2. ^
    doi:10.3847/1538-3881/aabfec
    .
  3. ^
    doi:10.1051/0004-6361/201629699
    .
  4. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR
    .
  5. S2CID 17174530
  6. ^ "Inclined Orbits Prevail in Exoplanetary Systems". 12 January 2011.
  7. S2CID 38743202
    .
  8. ^ 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.
  9. S2CID 119248079
    .
  10. PMID 31378171
    .
  11. doi:10.48392/lbj-001
    , retrieved 23 December 2021
  12. ^ "Astronomers Detect Signature of Magnetic Field on an Exoplanet". University of Arizona News. 20 December 2021. Retrieved 23 December 2021.
  13. ^ O'Callaghan, Jonathan (7 August 2023). "Exoplanets Could Help Us Learn How Planets Make Magnetism". Quanta Magazine. Retrieved 7 August 2023.

External links

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


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