Kepler-1625

Kepler-1625 is a 14th-magnitude solar-mass star located in the constellation of Cygnus approximately 7,200 light-years (2,200 parsecs) away. Its mass is within 5% of that of the Sun, but its radius is approximately 70% larger reflecting its more evolved state. A candidate gas giant exoplanet was detected by the Kepler Mission around the star in 2015,[8] which was later validated as a real planet to >99% confidence in 2016.[9] In 2018, the Hunt for Exomoons with Kepler project reported evidence for a Neptune-sized exomoon around this planet, based on observations from NASA's Kepler mission and the Hubble Space Telescope.[10][4] Subsequently, the evidence for and reality of this exomoon candidate has been subject to debate.[11][12][13][14]

Stellar characteristics

Kepler-1625 is an approximately solar-mass star and yet is 1.7 times larger in diameter.[4] Its effective temperature is around 5,550 K, slightly lower than that of the Sun.[15][4] These parameters suggest that Kepler-1625 may be a yellow subgiant nearing the end of its life, with an age of approximately 8.7 billion years.[4] The star has been observed to be photometrically quiet, with periodic variability below 0.02%.[13] Kepler-1625 is located approximately 7,200 light-years away[2] in the constellation Cygnus.[15]

Planetary system

The Kepler-1625 planetary system[4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≤11.6[16] MJ 0.98±0.14 287.3727±0.0022 — 89.97±0.02° 11.4±1.6 R🜨

The star is known to have one validated planet. Designated Kepler-1625b, it is a Jovian-sized planet orbiting its star every 287.3 Earth days. No other candidate transiting planets have been found around the star.[13]

Potential exomoon

Main article: Kepler-1625b I

The Kepler Mission recorded three planetary transits of Kepler-1625b from 2009 to 2013.[8] From these, anomalous out-of-transit flux decrements indicated the possible existence of a Neptune-sized exomoon, as first reported by the Hunt for Exomoons with Kepler project in 2018.[10] The Kepler data were inconclusive and so the planetary transit was re-observed by the Hubble Space Telescope in October 2018. The light curve from Hubble exhibited evidence for both a moon-like transit and a transit timing variation, both of which were consistent as being caused by the same Neptune-sized moon in orbit of Kepler-1625b.[4] The transit timing variation has been independently recovered by two teams analyzing the same data.[11][12] One of these teams also independently recovered the moon-like transit, but suggest that radial velocity measurements are needed to exclude the possibility of a close-in masquerading planet.[11] The other team are unable to recover the moon-like transit and suggested it may be an artifact of the data reduction.[12] This conclusion was challenged by the original team soon after, who showed that the other analysis exhibits larger systematics that may explain their differing conclusion.[13]

See also

References

  1. ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. ^ a b c d e f 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. ^ Furlan, E.; Ciardi, D. R.; Everett, M. E.; Saylors, M.; Teske, J. K.; Horch, E. P.; Howell, S. B.; Van Belle, G. T.; Hirsch, L. A.; Gautier, T. N., III; Adams, E. R.; Barrado, D.; Cartier, K. M. S.; Dressing, C. D.; Dupree, A. K.; Gilliland, R. L.; Lillo-Box, J.; Lucas, P. W.; Wang, J. (2017). "The Kepler Follow-up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging". The Astronomical Journal. 153 (2): 71. arXiv:1612.02392. Bibcode:2017AJ....153...71F. doi:10.3847/1538-3881/153/2/71.
  4. ^ a b c d e f g h i j k l m n Teachey, Alex; Kipping, David M. (2018). "Evidence for a Large Exomoon Orbiting Kepler-1625b". Science Advances. 4 (10): eaav1784. arXiv:1810.02362. Bibcode:2018SciA....4.1784T. doi:10.1126/sciadv.aav1784. PMC 6170104. PMID 30306135.
  5. ^ Mulders, Gijs D.; Pascucci, Ilaria; Apai, Dániel (2015). "An Increase in the Mass of Planetary Systems around Lower-mass Stars". The Astrophysical Journal. 814 (2): 130. arXiv:1510.02481. Bibcode:2015ApJ...814..130M. doi:10.1088/0004-637X/814/2/130.
  6. ^ "NASA Exoplanet archive". Retrieved 2017-07-28.
  7. ^ "Kepler-1625". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-19.
  8. ^ a b Mullally, Fergus; et al. (2015). "Planetary Candidates Observed by Kepler. VI. Planet Sample from Q1--Q16 (47 Months)". The Astrophysical Journal. 217 (2). 31. arXiv:1502.02038. Bibcode:2015ApJS..217...31M. doi:10.1088/0067-0049/217/2/31. S2CID 38448081.
  9. ^ Morton, Timothy D.; et al. (2016). "False Positive Probabilities for all Kepler Objects of Interest: 1284 Newly Validated Planets and 428 Likely False Positives". The Astrophysical Journal. 822 (2). 86. arXiv:1605.02825. Bibcode:2016ApJ...822...86M. doi:10.3847/0004-637X/822/2/86. S2CID 20832201.
  10. ^ a b Teachey, Alex; et al. (2018). "HEK VI: On the Dearth of Galilean Analogs in Kepler and the Exomoon Candidate Kepler-1625b I". The Astronomical Journal. 155 (1). 36. arXiv:1707.08563. Bibcode:2018AJ....155...36T. doi:10.3847/1538-3881/aa93f2. S2CID 118911978.
  11. ^ a b c Heller, Rene; Rodenbeck, Kai; Giovanni, Bruno (2019). "An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625". Astronomy and Astrophysics. 624: 95. arXiv:1902.06018. Bibcode:2019A&A...624A..95H. doi:10.1051/0004-6361/201834913. S2CID 119311103.
  12. ^ a b c Kreidberg, Laura; Luger, Rodrigo; Bedell, Megan (June 2019). "No Evidence for Lunar Transit in New Analysis of Hubble Space Telescope Observations of the Kepler-1625 System". The Astrophysical Journal Letters. 877 (2): L15. arXiv:1904.10618. Bibcode:2019ApJ...877L..15K. doi:10.3847/2041-8213/ab20c8. S2CID 129945202.
  13. ^ a b c d Teachey, Alex; Kipping, David M.; Burke, Christopher (2019). "Loose Ends for the Exomoon Candidate Host Kepler-1625b". The Astronomical Journal. 159 (4): 142. arXiv:1904.11896. Bibcode:2020AJ....159..142T. doi:10.3847/1538-3881/ab7001. S2CID 135465103.
  14. ^ Heller, René; Hippke, Michael (December 2023). "Large exomoons unlikely around Kepler-1625 b and Kepler-1708 b". Nature Astronomy. 8 (2): 193–206. arXiv:2312.03786. Bibcode:2024NatAs...8..193H. doi:10.1038/s41550-023-02148-w.
  15. ^ a b Mathur, Savita; Huber, Daniel; Batalha, Natalie M.; Ciardi, David R.; Bastien, Fabienne A.; Bieryla, Allyson; Buchhave, Lars A.; Cochran, William D.; Endl, Michael; Esquerdo, Gilbert A.; Furlan, Elise; Howard, Andrew; Howell, Steve B.; Isaacson, Howard; Latham, David W.; MacQueen, Phillip J.; Silva, David R. (2017). "Revised Stellar Properties of Kepler Targets for the Q1-17 (DR25) Transit Detection Run". The Astrophysical Journal Supplement Series. 229 (2): 30. arXiv:1609.04128. Bibcode:2017ApJS..229...30M. doi:10.3847/1538-4365/229/2/30. S2CID 39426786.
  16. ^ Timmermann, Anina; Heller, Rene; Reiner, Ansgar; Zechmeister, Mathias (2020). "Radial velocity constraints on the long-period transiting planet Kepler-1625 b with CARMENES". Astronomy and Astrophysics. 635: 59. arXiv:2001.10867. Bibcode:2020A&A...635A..59T. doi:10.1051/0004-6361/201937325. S2CID 210942758.