Kepler-89

Kepler-89

Observation data Epoch J2000      Equinox J2000
Constellation	Cygnus
Right ascension	19^h 49^m 19.9343^s[1]
Declination	+41° 53′ 28.006″[1]
Apparent magnitude (V)	12.4[2]
Characteristics
Spectral type	F8 V
Astrometry
Proper motion (μ)	RA: 2.063(10) mas/yr[1] Dec.: 1.337(11) mas/yr[1]
Parallax (π)	2.1069 ± 0.0086 mas[1]
Distance	1,548 ± 6 ly (475 ± 2 pc)
Details[3]
Mass	1.25+0.03 −0.04 M☉
Radius	1.61+0.11 −0.12 R☉
Surface gravity (log g)	4.123 ± 0.055 cgs
Temperature	6116 K
Metallicity [Fe/H]	−0.01 ± 0.04 dex
Rotational velocity (v sin i)	7.33 ± 0.32 km/s
Age	3.9+0.3 −0.2 Gyr
Other designations
Gaia DR2 2076970047474270208, KOI-94, KIC 6462863, 2MASS J19491993+4153280[4]
Database references
SIMBAD	data
KIC	data

Kepler-89 is a star with four confirmed planets. Kepler-89 is a possible wide binary star.^[5]

Planetary system

The discovery of four planets orbiting the star was announced October 2012 by analyzing data gathered by Kepler space telescope.^[3] Follow-up radial velocity measurements confirmed the existence of Kepler-89d, indicating that Kepler-89d is slightly larger and more massive than Saturn.^[6] In October 2013, other three planets were confirmed with Kepler-89c and Kepler-89e getting reasonable mass constraints. Transit-timing variations of the outermost planet suggest that additional planets or minor bodies are present in the system.^[7]

In 2012, a partial transit of the second outermost planet by the outermost planet was reported. This was the first time a planet-planet transit in front of the star was detected.^[8][3] This allowed to determine the mutual inclination of the planets d and e to be 1.15°.^[7]

Stephen R. Kane did a dynamical analysis of the Kepler-89 system that demonstrated that planets c and d, although close to the 2:1 secular resonance, are not permanently in a 2:1 resonance configuration.^[9]

The Kepler-89 planetary system

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	<10.5 M🜨	0.05	3.7	—	89.3°	0.13 RJ
c	7.3-11.8 M🜨	0.099	10.4	<0.1	88.36°	0.31 RJ
d	0.33±0.034 MJ	0.165	22.3	<0.1	89.871°	0.83 RJ
e	11.9-15.5 M🜨	0.298	54.3	<0.1	89.76°	0.49 RJ

References

1. 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.
2. "Planet Kepler-89 b". Extrasolar Planets Encyclopaedia. Retrieved 26 April 2018.
3. Hirano, Teruyuki; et al. (2012). "Planet-Planet Eclipse and the Rossiter-McLaughlin Effect of a Multiple Transiting System: Joint Analysis of the Subaru Spectroscopy and the Kepler Photometry". The Astrophysical Journal. 759 (2). L36. arXiv:1209.4362. Bibcode:2012ApJ...759L..36H. doi:10.1088/2041-8205/759/2/L36.
4. "Kepler-89". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-07.
5. Takahashi, Yasuhiro H.; Norio Narita; Teruyuki Hirano; Masayuki Kuzuhara; et al. (2013). "A Discovery of a Candidate Companion to a Transiting System KOI-94: A Direct Imaging Study for a Possibility of a False Positive". arXiv:1309.2559 [astro-ph.EP].
6. Weiss, Lauren M.; et al. (2013). "The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux". The Astrophysical Journal. 768 (1). 14. arXiv:1303.2150. Bibcode:2013ApJ...768...14W. doi:10.1088/0004-637X/768/1/14.
7. Masuda, Kento; et al. (2013). "Characterization of the KOI-94 System with Transit Timing Variation Analysis: Implication for the Planet-Planet Eclipse". The Astrophysical Journal. 778 (2). 185. arXiv:1310.5771. Bibcode:2013ApJ...778..185M. doi:10.1088/0004-637X/778/2/185.
8. "First ever discovery of planet-planet eclipse | UTokyo Research". u-tokyo.ac.jp. Archived from the original on 2013-11-04. Retrieved 2014-01-20.
9. Kane, Stephen R. (2019). "Orbital Stability and Precession Effects in the Kepler-89 System". The Astronomical Journal. 158 (2). 72. arXiv:1906.07193. Bibcode:2019AJ....158...72K. doi:10.3847/1538-3881/ab2a09.