Kepler-12b

Coordinates: Sky map 19h 04m 58.44s, +50° 02′ 25″
Source: Wikipedia, the free encyclopedia.
Kepler-12b
Discovery
Discovered byFortney et al.[1]
Discovery siteKepler spacecraft
Discovery datePublished September 5, 2011[1]
radial velocity/transit[1]
Orbital characteristics
0.0556 (± 0.0007)[2] AU
Eccentricity0.01[2]
4.4379637 (± 0.0007)[2] d
Inclination88.76 (±0.08)[2]
StarKepler-12
Physical characteristics
Mean radius
1.695 +0.028
−0.032[2] RJ
Mass0.431 (± 0.041)[2] MJ
Mean density
0.111 +0.011
−0.009[1] g cm−3
Temperature1711±223 K.[3]

Kepler-12b is a

transit
(cross in front of) their host stars. The discovery paper was published on September 5, 2011.

Discovery

false positive. Analysis of Kepler's early data yielded evidence of a transit signal around a star designated as KIC 11804465, later known as Kepler-12. The transit signal was designated KOI-20.[1]

The Keck Observatory collected observations to prove that Kepler-12b's signal was not actually caused by an eclipsing binary.

The

Hale telescope confirmed both the WIYN and Keck findings.[1]

Keck's HIRES instrument measured Kepler-12's radial velocity, which was used to find more of Kepler-12's characteristics (and, by extension, deduce the characteristics of KOI-20 itself). The radial velocity measurements eventually led to the confirmation of Kepler-12b as a planet.[1] Kepler's data in its first 1.5 years of operation was processed and analyzed, yielding Kepler-12b's radius, mass and density.[1]

The

Astrophysical Journal on September 5, 2011.[1]

Host star

Main article: Kepler-12

Kepler-12, known also as KIC 11804465 in the

light years) away from Earth. The star also has an apparent magnitude of 13.438, which means that it cannot be seen from Earth with the unaided eye.[4]

The star is slightly more massive, slightly more iron-rich and slightly hotter than the Sun. However, Kepler-12 is larger, with a radius of 1.483 times the Sun's radius.[4]

Characteristics

Kepler-12b is a Hot Jupiter, and (at the time of its discovery) was the least-irradiated of four Hot Jupiters experiencing a radius anomaly of approximately 1.7 times or more the mass of Jupiter. This radius anomaly entails Hot Jupiters experiencing massive radius increases for a reason not explained by scientific models. Although Kepler-12 is the least-irradiated of the four Hot Jupiters, its radius is just as large, suggesting that multiple mechanisms influencing the planet's inflation are at work.[1] Kepler-12b was compared to HD 209458 b in its discovery paper because both planets appear to release similar amounts of energy (flux); it was also compared to TrES-4b because of the similar radius of the planet.[1]

Kepler-12b has a mass of 0.431 Jupiters. Its radius of 1.695

K (some 5.8 times greater than Jupiter's equilibrium temperature). Additionally, Kepler-12b has an almost totally circular orbit, with an orbital eccentricity of less than 0.01.[4]

The planet is likely to be tidally locked to the parent star. In 2015, the planetary nightside temperature was estimated to be equal to 1711±223 K.[3] The brightest spot in the planetary atmosphere is shifted westward from the substellar point, indicating a strong winds.[5]

References

  1. ^
    S2CID 688362
    .
  2. ^ a b c d e f g Jean Schneider (2011). "Notes for star Kepler-12". Extrasolar Planets Encyclopaedia. Archived from the original on 5 October 2011. Retrieved 12 September 2011.
  3. ^ a b A Comprehensive Study of Kepler Phase Curves and Secondary Eclipses:Temperatures and Albedos of Confirmed Kepler Giant Planets
  4. ^ a b c "Datatable of Kepler Discoveries". Ames Research Center. NASA. 2011. Archived from the original on 2010-05-27. Retrieved 12 September 2011.
  5. S2CID 33182939


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