Astronomy:Kepler-553
Kepler-553 is a star in the northern constellation of Cygnus, approximately 2,430 light-years from the Solar System. It is a G-type subgiant that hosts two known exoplanets.[1][2]
Planetary system
Two exoplanets are known to orbit Kepler-553, both gas giants. The inner planet, Kepler-553b, is between Neptune and Saturn in size; the outer, Kepler-553c, is a super-Jupiter in the habitable zone.[3] The planets were discovered by NASA's Kepler space telescope using the transit method, and were confirmed in 2016 by a study that used statistical validation to confirm over 1,000 Kepler candidates.[4] They were later characterized with radial velocity measurements.[3]
Kepler-553 b
Kepler-553 b is a super-Neptune-sized planet (or a sub-Saturn) orbiting close to its host star. Its mass remains unconstrained beyond an upper limit due to the challenges in detecting its weak radial velocity signal.[3]
Kepler-553 c
Kepler-553 c is a massive gas giant with a moderate orbital eccentricity, orbiting within the system's habitable zone.[3] Its equilibrium temperature of approximately 251 K[3] makes it a cold giant, potentially analogous to Jupiter but with higher metallicity.[citation needed] The planet's bulk composition is estimated to be about 8% heavy elements by mass, consistent with expectations for a gas giant of its mass.[3]
Prior to its confirmation, this planet was known as KOI-433.02,[2] and a 2011 article from the Planetary Habitability Laboratory included it in a list of exoplanet candidates that could hypothetically host potentially habitable exomoons.[5] There is as yet no evidence of any moons around this planet.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | <0.365 MJ | 0.04766+0.00081 −0.00065 |
4.0304670(18) | — | 88.94+0.67 −0.60° |
0.423+0.016 −0.011 RJ |
| c | 6.70+0.44 −0.43 MJ |
0.898+0.015 −0.012 |
328.24017+0.00039 −0.00040 |
0.346+0.020 −0.024 |
89.8314+0.0054 −0.0092° |
1.033+0.032 −0.025 RJ |
References
- ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 "Kepler-553 | NASA Exoplanet Archive". https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-553.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Dalba, Paul A.; Kane, Stephen R.; Isaacson, Howard; Fulton, Benjamin; Howard, Andrew W.; Schwieterman, Edward W.; Thorngren, Daniel P.; Fortney, Jonathan et al. (2024-01-09), "Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. IV. Long-term Doppler Spectroscopy for 11 Stars Thought to Host Cool Giant Exoplanets", The Astrophysical Journal Supplement Series 271 (1): 16, doi:10.3847/1538-4365/ad18c3, Bibcode: 2024ApJS..271...16D
- ↑ Morton, Timothy D. et al. (May 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. doi:10.3847/0004-637X/822/2/86. Bibcode: 2016ApJ...822...86M.
- ↑ "Latest List of Potential Habitable Exoplanets and Exomoons". 30 September 2011. http://phl.upr.edu/library/notes/latestlistofpotentialhabitableexoplanetsandexomoons.
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