Not to be confused with the OLPC XO-4 from the One Laptop per Child (OLPC) initiative or the Martin XO-4.

XO-4 is a star located approximately 863 light-years away from Earth in the Lynx constellation. It has a magnitude of about 11 and cannot be seen with the naked eye but is visible through a small telescope.[3] A search for a binary companion star using adaptive optics at MMT Observatory was negative.[7]

The star XO-4 is named Koit. The name was selected in the NameExoWorlds campaign by Estonia, during the 100th anniversary of the IAU. Koit is Estonian for dawn, and was named for a character in a folk tale written by Friedrich Robert Faehlmann.[8][9][10]

Planetary system

One known exoplanet, XO-4b, which is classified as a hot Jupiter, orbits XO-4. This exoplanet was discovered in 2008 by the XO Project using the transit method.[3] It has been named Hämarik, meaning dusk, and referring to a character from the same Faehlmann story featuring Koit.[11] The planetary orbit is misaligned with the stellar rotation.[12]

The XO-4 planetary system[5][note 1]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b / Hämarik 1.612+0.027
−0.028 MJ 		0.05524+0.00027
−0.00028 		4.1250823(39) <0.0039 88.7±1.1° 1.34±0.05 RJ

Notes

  1. ^ eccentricity approximately equal to zero is expected theoretically and is consistent with the radial velocities and secondary eclipse timing[3][13]

References

  1. ^ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
  2. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b c d e f g h McCullough, P. R.; et al. (2008). "XO-4b: An Extrasolar Planet Transiting an F5V Star". arXiv:0805.2921 [astro-ph].
  4. ^ a b c Cutri; et al. (2003). "2MASS===07213317+5816051". 2MASS All-Sky Catalog of Point Sources. Retrieved 2012-02-25.
  5. ^ a b Bonomo, A. S.; Desidera, S.; et al. (June 2017). "The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy & Astrophysics. 602: A107. arXiv:1704.00373. Bibcode:2017A&A...602A.107B. doi:10.1051/0004-6361/201629882.
  6. ^ "SIMBAD query result: TYC 3793-1994-1 -- Star". Centre de Données astronomiques de Strasbourg. Retrieved 2009-04-26.
  7. ^ Adams, E. R.; et al. (2013). "Adaptive Optics Images. II. 12 Kepler Objects of Interest and 15 Confirmed Transiting Planets". The Astronomical Journal. 146 (1). 9. arXiv:1305.6548. Bibcode:2013AJ....146....9A. doi:10.1088/0004-6256/146/1/9. S2CID 119117620.
  8. ^ "Approved names". NameExoworlds. Retrieved 2020-01-02.
  9. ^ "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  10. ^ "Estonia has been assigned its own star and planet". Estonian World. 20 January 2020. Retrieved 2020-01-20.
  11. ^ "Estonia has been assigned its own star and planet". Estonian World. 20 January 2020. Retrieved 2020-01-20.
  12. ^ Narita, Norio; et al. (2010). "The Rossiter-McLaughlin Effect of the Transiting Exoplanet XO-4b". Publications of the Astronomical Society of Japan. 62 (6): L61 – L65. arXiv:1008.3803. Bibcode:2010PASJ...62L..61N. doi:10.1093/pasj/62.6.l61. S2CID 2967944.
  13. ^ Todorov, Kamen O.; et al. (2012). "Warm Spitzer Observations of Three Hot Exoplanets: XO-4b, HAT-P-6b, and HAT-P-8b". The Astrophysical Journal. 746 (1). 111. arXiv:1111.5858. Bibcode:2012ApJ...746..111T. doi:10.1088/0004-637X/746/1/111. S2CID 119200344.


Allikas: https://en.wikipedia.org/wiki/XO-4
No tags for this post.