Kepler-421b
Exoplanet | List of exoplanets | |
---|---|---|
Parent star | ||
Star | Kepler-421 | |
Constellation | Lyra | |
Right ascension | (α) | +18h 53m 1.64s |
Declination | (δ) | +45° 05′ 15.99″ |
Apparent magnitude | (mV) | 13.354 |
Distance | 1040 ly (320 ± 20 pc) | |
Spectral type | G9 or K0 | |
Mass | (m) | 0.790 M☉ |
Radius | (r) | 0.76 R☉ |
Temperature | (T) | 5308 K |
Orbital elements | ||
Semi-major axis | (a) | 1.219 AU |
Orbital period | (P) | 704.1984 d |
Inclination | (i) | 89.965° |
Physical characteristics | ||
Radius | (r) | 4.16 R⊕ |
Discovery information | ||
Discovery date | 2014 | |
Discoverer(s) | ||
Discovery method | Transit | |
Discovery site | Kepler telescope | |
Discovery status | Published | |
Other designations | ||
Database references | ||
Extrasolar Planets Encyclopaedia | data | |
SIMBAD | data | |
Exoplanet Archive | data | |
Open Exoplanet Catalogue | data |
Currently the known directly imaged planets are far from their star so have long years: GU-Piscium-b's year is 163,000 years long. The directly imaged planet with the shortest year is Beta-Pictoris-b with a year that takes 20 years. The transiting planets known so far are close to their stars: The transiting planet with the longest year is Kepler-421b with a year that lasts 704 days or about 2 years.[1] |
Kepler-421b is an exoplanet that, as of July 2014, has the longest known year of any transiting planet (704 days),[1] although not as long as the planets that have been directly imaged, or many of the planets found by the radial-velocity method, or as long as some transiting planet candidates which are listed as planets in the Extrasolar Planets Encyclopaedia (KIC 5010054 b etc.).[2] It is the first transiting-planet found near the snow-line.
Normally, at least three transits are required to confirm a planet. Due to very high signal to noise ratio, only two transits were sufficient to validate Kepler-421b to be a real planet without additional confirmation methods.
Kepler-421b is slightly larger than Uranus although its mass is not known.
References
- 1 2 Johnson, Michele (July 21, 2014). "Astronomers Discover Transiting Exoplanet with Longest Known Year". NASA. Retrieved July 25, 2014.
- ↑ http://exoplanet.eu/catalog/?f=%22transit%22+IN+detection
Further reading
- The Longest Year, Phil Plait, Slate, July 23, 2014
- New Exoplanet Has the Longest Year Ever Discovered, July 23, 2014 at 2:15:00 PM by Niko Vercelletto, Popular Mechanics
- Astronomers discover exoplanet with longest known year, Anthony Wood, July 23, 2014, Gizmag
- First Exoplanet Discovered Beyond the “Snow Line”, by Shannon Hall on July 22, 2014, Universe Today
- Transiting Exoplanet With Longest Known Year Discovered By Kepler Mission, July 22, 2014, RedOrbit
- Discovery of a Transiting Planet Near the Snow-Line, David M. Kipping, Guillermo Torres, Lars A. Buchhave, Scott J. Kenyon, Christopher E. Henze, Howard Isaacson, Rea Kolbl, Geoff W. Marcy, Stephen T. Bryson, Keivan G. Stassun, Fabienne A. Bastien, (Submitted on 17 Jul 2014)
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