KOI-868.01, also known by its Kepler Input Catalog designation KIC 6867155.01,[1] is a Saturn-sized exoplanet candidate that orbits the M-type star KOI-868,[1][2] located approximately 1,315 light years away in the constellation of Cygnus.[1][2]
Host star
The planet candidate orbits the dim red dwarf star KOI-868, which has a spectral type of M1V.[2][3] The star has an apparent visual magnitude of 15.643, and is roughly 1,300 light years away in the constellation of Cygnus.[2] The star has an effective temperature of 3,822 K.[3] KOI-868 has a radius of 0.53 solar radii (R☉; 370,000 km), and has a mass of 0.55 solar masses (M☉; 1.09×1030 kg).[3]
Characteristics
KOI-868.01 is similar in size to Saturn with an estimated radius of 0.945 RJ, or a diameter of roughly 120,000 kilometers.[1] The unconfirmed planet has a mass of 0.689 MJ, or 219.1 M🜨.[4] The potential planet orbits its star in 236 days at a distance of 0.65 astronomical units.[1] The planet candidate is located within the habitable zone of its star, and has an equilibrium temperature of 188 K (−85 °C; −121 °F).[1] The planet was first suggested to exist as a Kepler Object of Interest (KOI) in 2013 after observations with the Kepler Space Telescope using the transit method.[1]
Existence
KOI-868.01 is currently categorized as a planet candidate by the NASA Exoplanet Archive (NEA).[1] In 2026, it was found that KOI-868.01 is an extremely promising candidate, along with several others, and further studies could confirm the existence of this planet.[5]
Potential ring system
In 2018, it was discovered that KOI-868.01 may host rings due to an anomaly during the transits.[6] Using the data from the transit, the study found that the predicted rings potentially extend up to 88,000 kilometers from the surface of the planet.[6] It was found that the hypothetical rings would be stable for over 3 billion years.[6] However, with only two transits, the existence of rings is unlikely, and the anomalies observed is believed to be caused by stellar activity.[6]
Possible exomoon
In 2015, David Kipping discovered using transit timing variations (shortened as TTVs) that a potential exomoon may orbit KOI-868.01 in the Hunt for Exomoons with Kepler (abbreviated as HEK) project.[7] The possible exomoon, which is named KOI-868.01 I, would have a radius of 1.23 R🜨, and a mass of 0.31 M🜨.[4] The candidate exomoon would orbit approximately 0.0221 astronomical units away from the planet.[4] Because KOI-868.01 is located in the habitable zone of its star, this exomoon could potentially be an example of a habitable exomoon similar to 2MASS J1119-1137 I.[7]
See also
- List of exomoon candidates, includes KOI-868.01.
- 2MASS J1119-1137, another system containing a potentially habitable exomoon.
References
- 1 2 3 4 5 6 7 8 “KOI-868 System Overview”. NASA Exoplanet Archive. Retrieved 2026-02-20.
- 1 2 3 4 “SIMBAD Results for KOI-868”. SIMBAD. Retrieved 2026-02-20.
- 1 2 3 Muirhead, Philip (2012). “Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars”. NASA ADS. Retrieved 2026-02-20.
- 1 2 3 Guimarães, Ana (2018). “The Best Planets to Harbor Detectable Exomoons”. NASA ADS. Retrieved 2026-02-21.
- ↑ D’Angiolillo, Skylar (2026). “Accounting for Transit Timing Detectability: Biases in Planetary Radius and Orbital Period”. NASA ADS. Retrieved 2026-03-09.
- 1 2 3 4 Aizawa, Masataka (2018). “Systematic Search for Rings around Kepler Planet Candidates: Constraints on Ring Size and Occurrence Rate”. NASA ADS. Retrieved 2026-02-20.
- 1 2 Kipping, David (2015). “The Hunt for Exomoons with Kepler (HEK): V. A Survey of 41 Planetary Candidates for Exomoons”. NASA ADS. Retrieved 2026-02-21.