Kepler-78b

from Wikipedia, the free encyclopedia
Exoplanet
Kepler-78b

Kepler-78b in close proximity to the central star (symbol illustration.)

Kepler-78b in close proximity to the central star (symbol illustration.)
Constellation swan
Position
equinox : J2000.0
Right ascension 19h 34m 58.01s
declination + 44 ° 26 ′ 24.0 ″
Orbit data
Central star Kepler-78
Major semi-axis 0.01  + 0.0025−0.011 AE
Period of circulation 8.52 h
Further data
radius 1.20  +0.09−0.09 R ⊕
Dimensions 1.69  +0.41−0.41 M ⊕
distance 124 pc
history
Catalog names
KIC 8435766 b, 2MASS J19345800 + 4426539 b, WISE J193458.03 + 442653.7 b

Kepler-78b (formerly KIC 8435766 b ) is an exoplanet discovered in 2013 at a distance of around 124 parsecs (around 405 light years ) from Earth. It orbits the star Kepler-78 in the constellation Cygnus (Swan) at a distance of less than 1.6 million kilometers. Its origin is unclear due to the close proximity to its central star. Its orbit is not in the habitable zone .

discovery

The planet was discovered with the help of the Kepler space telescope. This telescope records brightness fluctuations that occur when a planet, viewed from Earth, passes exactly in front of its central star (see transit method ). With the help of the data, an initial estimate of the radius of the planet Kepler-78b as well as its distance from the parent star, its orbital period and its surface temperature could be made. Follow-up observations from the ground helped to make these values ​​more precise and also to determine its mass and density .

properties

The star orbited by Kepler-78b belongs to the spectral class K2. The extrasolar planet needs about 8.5 hours for one orbit. The distance from Kepler-78b to its central star is only one hundredth of the distance between the earth and the sun. Because of this close proximity to its star, the temperature is estimated at 2200 to 2800 ° C. Thus, the orbit is not in the habitable zone . The surface is probably characterized by hot, molten rock ( lava ).

Size comparison between the earth and Kepler-78b.

The mass of Kepler-78b is around 169% that of Earth, while it is only 20% larger. The density is roughly the same as that of the earth. From this it is concluded that it also consists mainly of rock and iron. Between 20 and 60% of the incident light is reflected.

It belongs to a newly discovered class of earth-sized planets that orbit their star in less than 12 hours and is the first planet in this group whose mass has now been determined. Its origin is still unclear. For one thing, it cannot have originated in such close proximity to Kepler, since the star was larger at the time it was formed and the current position would then have been in it. On the other hand, it is not possible that he subsequently hiked to this position, as in this case he would have fallen into the star. It is believed that Kepler-78b will break over the next 3 billion years because of the tidal force created by the star's gravity .

Web links

Individual evidence

  1. ↑ Gaia Collaboration, AGA Brown, A. Vallenari, T. Prusti, JHJ de Bruijne: Gaia Data Release 2: Summary of the contents and survey properties . In: Astronomy & Astrophysics . tape 616 , 2018, ISSN  0004-6361 , p. A1 , doi : 10.1051 / 0004-6361 / 201833051 ( aanda.org [accessed May 6, 2019]).
  2. ↑ a b c d e f g h Roberto Sanchis-Ojeda, Saul Rappaport, Joshua N. Winn, Alan Levine, Michael C. Kotson: TRANSITS AND OCCULTATIONS OF AN EARTH-SIZED PLANET IN AN 8.5 hr ORBIT . In: The Astrophysical Journal . tape 774 , no. 1 , August 16, 2013, ISSN  0004-637X , p. 54 , doi : 10.1088 / 0004-637X / 774/1/54 ( iop.org [accessed May 4, 2019]).
  3. ↑ a b c d Andrew W. Howard, Roberto Sanchis-Ojeda, Geoffrey W. Marcy, John Asher Johnson, Joshua N. Winn: A rocky composition for an Earth-sized exoplanet . In: Nature . tape 503 , no. 7476 , November 2013, ISSN  0028-0836 , p. 381–384 , doi : 10.1038 / nature12767 ( nature.com [accessed May 4, 2019]).
  4. ↑ a b c d Francesco Pepe, Andrew Collier Cameron, David W. Latham, Emilio Molinari, Stéphane Udry: An Earth-sized planet with an Earth-like density . In: Nature . tape 503 , no. 7476 , November 2013, ISSN  0028-0836 , p. 377-380 , doi : 10.1038 / nature12768 ( nature.com [accessed May 4, 2019]).
  5. ^ A b C. AL Bailer-Jones, J. Rybizki, M. Fouesneau, G. Mantelet, R. Andrae: Estimating Distance from Parallaxes. IV. Distances to 1.33 Billion Stars in Gaia Data Release 2 . In: The Astronomical Journal . tape 156 , no. 2 , July 20, 2018, ISSN  1538-3881 , p. 58 , doi : 10.3847 / 1538-3881 / aacb21 ( iop.org [accessed May 4, 2019]).
  6. ↑ a b Elizabeth Gibney: Exoplanet is built like Earth but much, much hotter . In: Nature . October 30, 2013, ISSN  1476-4687 , doi : 10.1038 / nature.2013.14058 ( nature.com [accessed on May 4, 2019]).
  7. ^ A. Frasca, J. Molenda-Żakowicz, P. De Cat, G. Catanzaro, JN Fu: Activity indicators and stellar parameters of the Kepler targets: An application of the ROTFIT pipeline to LAMOST-Kepler stellar spectra ⋆⋆⋆ . In: Astronomy & Astrophysics . tape 594 , October 2016, ISSN  0004-6361 , p. A39 , doi : 10.1051 / 0004-6361 / 201628337 ( aanda.org [accessed May 4, 2019]).
  8. ↑ Nina Weber: Exoplanet: Astronomers discover the earth twin. In: Spiegel Online . October 30, 2013, accessed June 10, 2018 .
  9. ^ A b Christine Pulliam, David A. Aguilar: Mystery World Baffles Astronomers . In: Center for Astrophysics . October 28, 2013. Retrieved May 12, 2019.