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,[5] which was later validated as a real planet to >99% confidence in 2016.[6] 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.[7][3] Subsequently, the evidence for and reality of this exomoon candidate has been subject to debate.[8][9][10][11]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 41m 43.04008s[1] |
| Declination | +39° 53′ 11.4990″[1] |
| Characteristics | |
| Apparent magnitude (K) | 13.916[2] |
| Astrometry | |
| Proper motion (μ) | RA: −2.088(32) mas/yr[1] Dec.: −4.804(32) mas/yr[1] |
| Parallax (π) | 0.4548 ± 0.0289 mas[1] |
| Distance | 7,200 ± 500 ly (2,200 ± 100 pc) |
| Details | |
| Mass | 1.04±0.08[3] M☉ |
| Radius | 1.73±0.24[3] R☉ |
| Luminosity (bolometric) | 2.57±0.68[3] L☉ |
| Surface gravity (log g) | 3.99±0.10[3] cgs |
| Temperature | 5563±86[3] K |
| Metallicity [Fe/H] | 0.06±0.13[3] dex |
| Age | 8.7±2.1[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Stellar characteristics
editKepler-1625 is an approximately solar-mass star and yet is 1.7 times larger in diameter.[3] Its effective temperature is around 5,550 K, slightly lower than that of the Sun.[12][3] 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.[3] The star has been observed to be photometrically quiet, with periodic variability below 0.02%.[10] Kepler-1625 is located approximately 7,200 light-years away[1] in the constellation Cygnus.[12]
Planetary system
edit| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≤11.6[13] 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.[10]
Potential exomoon
editThe Kepler Mission recorded three planetary transits of Kepler-1625b from 2009 to 2013.[5] 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.[7] 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.[3] The transit timing variation has been independently recovered by two teams analyzing the same data.[8][9] 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.[8] The other team are unable to recover the moon-like transit and suggested it may be an artifact of the data reduction.[9] 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.[10]
See also
editReferences
edit- ^ 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.
- ^ "NASA Exoplanet archive". Retrieved 2017-07-28.
- ^ a b c d e f g h i j k l m Teachey, Alex; Kipping, David M. (2018). "Evidence for a Large Exomoon Orbiting Kepler-1625b" (PDF). Science Advances. 4 (10): eaav1784. arXiv:1810.02362. Bibcode:2018SciA....4.1784T. doi:10.1126/sciadv.aav1784. PMC 6170104. PMID 30306135. Archived from the original (PDF) on 2019-04-25. Retrieved 2019-04-25.
- ^ "Kepler-1625". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-19.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.