Kepler-452

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Kepler-452

Artist's impression of the Kepler-452 and Kepler-186 systems compared to the inner Solar System, with their respective habitable zones shown.
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 44m 00.8861s[1]
Declination +44° 16′ 39.1704″[1]
Apparent magnitude (V) 13.426[2]
Characteristics
Evolutionary stage Main sequence
Spectral type G2V[3]
Astrometry
Proper motion (μ) RA: 9.974±0.029[1] mas/yr
Dec.: 9.012±0.042[1] mas/yr
Parallax (π)1.7838 ± 0.0169 mas[1]
Distance1,830 ± 20 ly
(561 ± 5 pc)
Details
Mass1.037+0.054
−0.047 M☉
Radius1.11+0.15
−0.09 R☉
Luminosity1.2 L☉
Surface gravity (log g)4.32 ± 0.09 cgs
Temperature5757 ± 85 K
Metallicity [Fe/H]0.21 ± 0.09 dex
Age6 ± 2 Gyr
Other designations
Gaia DR2 2079597124345617280, KOI-7016, KIC 8311864, GSC 3148-814, 2MASS J19440088+4416392[4]
Database references
SIMBADdata
Exoplanet Archivedata
KICdata
Extrasolar Planets
Encyclopaedia		data

Kepler-452 is a G-type main-sequence star located about 1,800 light-years away from Earth[1] in the Cygnus constellation.[5] Although similar in temperature to the Sun, it is 20% brighter, 3.7% more massive and 11% larger.[6][7] Alongside this, the star is approximately six billion years old and possesses a high metallicity.[3]

Nomenclature and history[edit]

The Kepler Space Telescope search volume, in the context of the Milky Way Galaxy.

Prior to Kepler observation, Kepler-452 had the 2MASS catalogue number 2MASS 19440088+4416392. In the Kepler Input Catalog, it has the designation of KIC 8311864. When it was found to have a transiting planet candidate, it was given the Kepler object of interest number of KOI-7016.

Planetary candidates were detected around the star by NASA's Kepler Mission, a mission tasked with discovering planets in transit around their stars. The transit method that Kepler uses involves detecting dips in brightness of stars. These dips in brightness can be interpreted as planets whose orbits pass in front of their stars from the perspective of Earth, although other phenomena can also be responsible which is why the term "planetary candidate" is used.[8]

Following the acceptance of the discovery paper, the Kepler team referred to the star as Kepler-452, which is the normal procedure for naming exoplanets discovered by the spacecraft.[9][3] Hence, this is the name usually used by the public to refer to the star and its planet.

Candidate planets that are associated with stars studied by the Kepler Mission are assigned the designations ".01", ".02", and so on, after the star's name, in the order of discovery.[2] If planet candidates are detected simultaneously, then the ordering follows the order of orbital periods from shortest to longest.[2] Following these rules, there was only one candidate planet detected, with an orbital period of 384.843 days. The name Kepler-452 derives directly from the fact that the star is the catalogued 452nd star discovered by Kepler to have confirmed planets.

The designation b, derives from the order of discovery. The designation of b is given to the first planet orbiting a given star, followed by the other lowercase letters of the alphabet.[10] In the case of Kepler-452, there was only one planet, so only the letter b is used.

Stellar characteristics[edit]

Kepler-452 is a G-type star that is approximately 104% the mass of and 111% the radius of the Sun. It has a temperature of 5757 K and is roughly 6 billion years old. In comparison, the Sun is about 4.6 billion years old[11] and has a temperature of 5778 K.[12]

The star is metal-rich, with a metallicity (Fe/H) of about 0.21, or about 162% of the amount of iron and other heavier metals found in the Sun.[3] The star's luminosity is somewhat normal for a star like Kepler-452, with a luminosity of around 120% of that of the solar luminosity.

The star's apparent magnitude, or how bright it appears from Earth's perspective, is 13.426. Therefore, it is too dim to be seen with the naked eye.

Planetary system[edit]

The Kepler-452 planetary system[13]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 5 ± 2[14] M🜨 1.046+0.019
−0.015 		384.843+0.007
−0.012 		— 89.806+0.134
−0.049° 		1.5+0.32
−0.22 R🜨

The star hosts one confirmed exoplanet, Kepler-452b, discovered in July 2015 by the Kepler spacecraft. This planet is mostly known for its characteristics similar to Earth, most notably its size, orbit and stellar flux. It is the first potentially rocky super-Earth[15] planet discovered orbiting within the habitable zone and the abiogenesis zone of a star very similar to the Sun.[6][16] It may even have a surface temperature similar to that of Earth (the planet has an equilibrium temperature of approximately 265 K (−8 °C; 17 °F) (Earth's equilibrium temperature is only 10 K cooler than this). However, its star is 6 billion years old (roughly 1.5 billion years older than the Sun). Due to this, Kepler-452b is receiving roughly 10% more stellar radiation than the Earth does today. If Kepler-452b is a rocky planet, it might be subject to a runaway greenhouse effect. However, because of its mass (estimated to be about 5 ME), it may be able to prevent succumbing to the runaway greenhouse for a limited amount of time (at most about 500 million years). Nevertheless, the planet is one of the most Earth-like planets discovered so far by the Kepler team. Both the Earth and Kepler-452b are at just the right distances from their stars so that water can be liquid, at a temperature between 0 °C and 100 °C.[17]

Sun comparison[edit]

This table compares the Sun to Kepler-452.

Identifier J2000 Coordinates Distance
(ly) 		Stellar
Class 		Temperature
(K) 		Metallicity
(dex) 		Age
(Gyr) 		Notes
Right ascension Declination
Sun — — 0.00 G2V 5,778 +0.00 4.6 [18]
Kepler-452 [19] 19h 44m 00.89s +44° 16′ 39.2″ 1,800 G2V 5,757 +0.21 6.0 [20]

References[edit]

  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c "Kepler Input Catalog search result". Space Telescope Science Institute. Retrieved 25 July 2015.
  3. ^ a b c d Jenkins, Jon M.; Twicken, Joseph D.; Batalha, Natalie M.; Caldwell, Douglas A.; Cochran, William D.; Endl, Michael; et al. (2015). "Discovery and validation of Kepler-452b: A 1.6 R🜨 super Earth exoplanet in the habitable zone of a G2 star". The Astronomical Journal. 105 (2). Institute of Physics: 56. arXiv:1507.06723. Bibcode:2015AJ....150...56J. doi:10.1088/0004-6256/150/2/56. S2CID 26447864.
  4. ^ "Kepler-452". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 19 August 2020.
  5. ^ Witze, Alexandra (23 July 2015). "NASA spies Earth-sized exoplanet orbiting Sun-like star". Nature. Retrieved 23 July 2015.
  6. ^ a b Chou, Felicia; Johnson, Michelle (23 July 2015). "NASA's Kepler Mission Discovers Bigger, Older Cousin to Earth" (Press release). NASA. Retrieved 23 July 2015.
  7. ^ Rincon, Paul (23 July 2015). "'Earth 2.0' found in Nasa Kepler telescope haul". BBC. Retrieved 23 July 2015.
  8. ^ Morton, Timothy; Johnson, John (23 August 2011). "On the Low False Positive Probabilities of Kepler Planet Candidates". The Astrophysical Journal. 738 (2): 170. arXiv:1101.5630. Bibcode:2011ApJ...738..170M. doi:10.1088/0004-637X/738/2/170. S2CID 35223956.
  9. ^ NASA (27 January 2014). "Kepler – Discoveries – Summary Table". NASA. Archived from the original on 27 May 2010. Retrieved 1 March 2014.
  10. ^ Hessman, Frederic V.; Dhillon, Vikram S.; Winget, Donald E.; Schreiber, Matthias R.; Horne, Keith; Marsh, Thomas R.; Guenther, Eike W.; Schwope, Axel D.; Heber, Ulrich (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  11. ^ Williams, Matt (9 May 2016). "Life Cycle of the Sun". Universe Today. Retrieved 17 August 2016.
  12. ^ Cain, Fraser (23 December 2015). "What Color is the Sun?". Universe Today. Retrieved 17 August 2016.
  13. ^ "NASA Exoplanet Archive – Confirmed Planet Overview – Kepler-452b". NASA Exoplanet Archive. 2015. Retrieved 23 July 2015.
  14. ^ "NASA's Kepler Mission Discovers Bigger, Older Cousin to Earth". National Aeronautics and Space Administration. 23 July 2015. Archived from the original on 15 August 2015. Retrieved 10 June 2016.
  15. ^ "The Habitable Exoplanets Catalog – Planetary Habitability Laboratory @ UPR Arecibo". upr.edu.
  16. ^ "Super-earth 'most likely' candidate for hosting alien life". Sky News. Retrieved 3 August 2018.
  17. ^ Norton, Andrew. "Could humans live on Kepler 452-b?". The Conversation.
  18. ^ Williams, David R. (2004). "Sun Fact Sheet". NASA. Retrieved 23 June 2009.
  19. ^ Kepler-452 at SIMBAD - Ids - Bibliography - Image.
  20. ^ "Planet Kepler-452 b (sic)". Extrasolar Planets Encyclopaedia. Retrieved 6 July 2016.
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