Kepler-438

Kepler-438

Observation data Epoch J2000       Equinox J2000
Constellation	Lyra [1]
Right ascension	18h 46m 34.9968s [2]
Declination	+41° 57′ 03.934″ [2]
Apparent magnitude  (V)	15.0 [3]
Characteristics
Variable type	Flare star [4]
Astrometry
Proper motion (μ)	RA: −16.649(115) mas/yr [2] Dec.: −5.614(111) mas/yr [2]
Parallax (π)	5.5592±0.0984  mas [2]
Distance	590 ± 10  ly (180 ± 3  pc)
Absolute magnitude  (MV)	9.55+0.54 −0.44 [5]
Details [5]
Mass	0.544+0.061 −0.041  M☉
Radius	0.52+0.061 −0.038  R☉
Luminosity	0.044+0.017 −0.012  L☉
Surface gravity (log g)	4.74  cgs
Temperature	3748±112  K
Metallicity [Fe/H]	0.16±0.14  dex
Age	4.4+0.7 −0.8  Gyr
Other designations
KIC 6497146, KOI-3284, 2MASS J18463499+4157039 [6]
Database references
SIMBAD	data
KIC	data

Kepler-438 is a red dwarf in the constellation Lyra, about 590 light years from Earth. ^[2] It is notable for its planetary system, which includes Kepler-438b, a possibly Earth-size planet within Kepler-438's habitable zone. Kepler-438 is a flare star that undergoes random, dramatic increases in brightness due to flare activity. It emits strong superflares every few hundred days, with each flare being stronger than the most powerful flare recorded on the Sun. ^[7]

Planetary system

The system has one confirmed planet. However, transit timing observations of Kepler-438b indicate the possible presence of additional planets. ^[8]

The Kepler-438 planetary system ^{[5] [3]}

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	—	0.166 +0.051 −0.042	35.23319 +0.00025 −0.00029	0.03 +0.10 −0.03	89.86 +0.14 −0.32 °	1.12 +0.16 −0.17  R🜨

In 2022, a preprint described a narrowband radio signal that "[met] initial criteria for extraterrestrial intelligence" emitted from one of the Kepler-438 planets and received by astronomers at the Five-hundred-meter Aperture Spherical Telescope (FAST) in China. ^[9] The signal was later determined to be of terrestrial origin. ^[10]

References

1. Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR.
2. 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.
3. "Notes on Kepler-438 b". Extrasolar Planets Encyclopaedia . Retrieved 21 January 2017.
4. https://simbad.cds.unistra.fr/simbad/sim-id?Ident=Kepler-438
5. Torres, Guillermo; et al. (2015). "Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone". American Astronomical Society. 225: 438.02. arXiv: 1501.01101 . Bibcode:2015AAS...22543802C. doi:10.1088/0004-637X/800/2/99. S2CID   8512655.
6. "KOI-3284". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 21 January 2017.
7. "Most Earthlike exoplanet is uninhabitable" . Retrieved 30 January 2025.
8. Kipping, D. M.; et al. (2014). "The Hunt for Exomoons with Kepler (HEK). IV. A Search for Moons around Eight M Dwarfs". The Astrophysical Journal. 784 (1). 28. arXiv: 1401.1210 . Bibcode: 2014ApJ...784...28K . doi: 10.1088/0004-637X/784/1/28 .
9. Ling Xin (June 15, 2022). "Alien hunters detect mystery radio signal from direction of Earthlike planet". South China Morning Post . Narrowband signal picked up from direction of the Kepler-438 star meets initial criteria for extraterrestrial intelligence, preprint says; orbiting Kepler-438 in its habitable zone is one of the most Earthlike planets ever found outside the solar system.
10. Overbye, Dennis (June 18, 2022). "A Chinese Telescope Did Not Find an Alien Signal. The Search Continues". The New York Times .

External links

• NASA's Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones