Possible exomoon orbiting Kepler-1625b in the constellation of Cygnus
 Exomoon Kepler-1625b I orbiting exoplanet Kepler-1625b (artist concept). | |
| Discovery | |
|---|---|
| Discovered by | Alex Teachey, David M. Kipping and Allan R. Schmitt |
| Discovery date | 2017 |
| Detection method | Primary transit |
| Orbital characteristics | |
| Satellite of | Kepler-1625b |
| Physical characteristics | |
| Mean radius | 0.437 RJ |
| Mass | 19.069 M🜨 0.06 MJ |
| Mean density | 0.95 g/cm |
Kepler-1625b I is a possible moon of exoplanet Kepler-1625b, which may be the first exomoon ever discovered (pending confirmation), and was first indicated after preliminary observations by the Kepler Space Telescope. A more thorough observing campaign by the Hubble Space Telescope took place in October 2017, ultimately leading to a discovery paper published in Science Advances in early October 2018. Studies related to the discovery of this moon suggest that the host exoplanet is up to several Jupiter masses in size, and the moon is thought to be approximately the mass of Neptune. Like several moons in the Solar System, the large exomoon would theoretically be able to host its own moon, called a subsatellite, in a stable orbit, although no evidence for such a subsatellite has been found.
Studies and observations
The original paper presented two independent lines of evidence for the exomoon, a transit timing variation indicating a Neptune-mass moon, and a photometric dip indicating a Neptune-radius moon. An independent re-analysis of the observations published in February 2019 recovered both but suggested that an inclined and hidden hot-Jupiter could also be responsible, which could be tested with future Doppler spectroscopy radial velocity observations. A third study analyzing this data set recovered the transit timing variation signature but not the photometric dip, and thus questioned the exomoon hypothesis. The original discovery team later addressed this paper, finding that their re-reduction exhibits higher systematics that may explain their differing conclusions.
See also
References
- Chou, Felicia; Villard, Ray; Hawkes, Alison; Brown, Katherine (3 October 2018). "Astronomers Find First Evidence of Possible Moon Outside Our Solar System". NASA. Retrieved 5 October 2018.
- ^ Teachey, Alex; et al. (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.
- "The Extrasolar Planet Encyclopaedia — Kepler-1625 b I". Extrasolar Planets Encyclopaedia. Archived from the original on 5 October 2018. Retrieved 7 October 2018.
- Teachey, A.; Kipping, D. M.; Schmitt, A. R. (26 July 2017). "HEK. VI. On the Dearth of Galilean Analogs in Kepler, and the Exomoon Candidate Kepler-1625b I". The Astronomical Journal. 155 (1) (published 22 December 2017): 36. arXiv:1707.08563. Bibcode:2018AJ....155...36T. doi:10.3847/1538-3881/aa93f2. S2CID 118911978.
- Kollmeier, Juna A.; Raymond, Sean N. (21 November 2018). "Can moons have moons?". Monthly Notices of the Royal Astronomical Society: Letters. 483: L80–L84. arXiv:1810.03304. doi:10.1093/mnrasl/sly219.
- Forgan, Duncan H. (11 February 2019). "The habitable zone for Earth-like exomoons orbiting Kepler-1625b". International Journal of Astrobiology. 18 (6): 510–517. arXiv:1810.02712. Bibcode:2019IJAsB..18..510F. doi:10.1017/s1473550418000514. ISSN 1473-5504. S2CID 118857039.
- Heller, René; Rodenbeck, Kai; Giovanni, Bruno (17 April 2019). "An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625". Astronomy & Astrophysics. 624: 95. arXiv:1902.06018. Bibcode:2019A&A...624A..95H. doi:10.1051/0004-6361/201834913. S2CID 119311103.
- Kreidberg, Laura; Luger, Rodrigo; Bedell, Megan (24 May 2019). "No Evidence for Lunar Transit in New Analysis of Hubble Space Telescope Observations of the Kepler-1625 System". The Astrophysical Journal. 877 (2): L15. arXiv:1904.10618. Bibcode:2019ApJ...877L..15K. doi:10.3847/2041-8213/ab20c8. S2CID 129945202.
- Teachey, Alex; Kipping, David M.; Burke, Christopher (5 March 2020). "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.
