HAT-P-11b

HAT-P-11b (or Kepler-3b) is an extrasolar planet orbiting the star HAT-P-11. It was discovered by the HATNet Project team in 2009 using the transit method, and submitted for publication on 2 January 2009.

HAT-P-11b / Kepler-3b
Size comparison of Neptune with HAT-P-11b (gray).
Discovery[1]
Discovered byBakos et al.
Discovery siteCambridge, Massachusetts
Discovery date2 January 2009
Transit (HATNet)
Orbital characteristics
Apastron0.0637+0.0020
−0.0019 AU
Periastron0.0413+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] M🜨
Mean density
1,440 kg/m3 (2,430 lb/cu yd)
1.20 g

    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 field of view of the 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. 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.
    2. Yee, Samuel W.; et al. (2018). "HAT-P-11: Discovery of a Second Planet and a Clue to Understanding Exoplanet Obliquities". The Astronomical Journal. 155 (6). 255. arXiv:1805.09352. Bibcode:2018AJ....155..255Y. doi:10.3847/1538-3881/aabfec.
    3. Huber, K. F.; Czesla, S.; Schmitt, J. H. M. M. (2017). "Discovery of the secondary eclipse of HAT-P-11 b". Astronomy and Astrophysics. 597. A113. arXiv:1611.00153. Bibcode:2017A&A...597A.113H. doi:10.1051/0004-6361/201629699.
    4. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
    5. 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
    6. "Inclined Orbits Prevail in Exoplanetary Systems". 12 January 2011.
    7. Roberto Sanchis-Ojeda; Josh N. Winn; Daniel C. Fabrycky (2012). "Starspots and spin-orbit alignment for Kepler cool host stars". Astronomische Nachrichten. 334 (1–2): 180–183. arXiv:1211.2002. Bibcode:2013AN....334..180S. doi:10.1002/asna.201211765. 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. Hodosán, G.; Rimmer, P. B.; Helling, Ch. (2016). "Lightning as a possible source of the radio emission on HAT-P-11b". Monthly Notices of the Royal Astronomical Society. ADS. 461 (2): 1222–1226. arXiv:1604.07406. Bibcode:2016MNRAS.461.1222H. doi:10.1093/mnras/stw977. S2CID 119248079.
    10. Helling, Christiane; Rimmer, Paul B. (23 September 2019). "Lightning and charge processes in brown dwarf and exoplanet atmospheres". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 377 (2154): 20180398. Bibcode:2019RSPTA.37780398H. doi:10.1098/rsta.2018.0398. PMC 6710897. PMID 31378171.
    11. Ben-Jaffel, Lotfi; Ballester, Gilda (2021), Signatures of Strong Magnetization and Metal-poor Atmosphere for a Neptune-Size Exoplanet, Institut d'astrophysique de Paris-CNRS, 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.

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

    This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.