Kepler-93b

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Kepler-93b
Discovery
Discovered byGeoffrey W. Marcy et al. [1]
Discovery dateFebruary 2014 (announced)[1]
Transit method
Designations
KIC 3544595 b, KOI-69.01, BD+38 3583b, TYC 3134-218-1 b[2]
Orbital characteristics
0.053±0.002[3] AU
Eccentricity0
4.72673978±0.0000009 [4] d
Inclination89.183±0.044[3]
StarKepler-93
Physical characteristics
Mean radius
1.478±0.019[4] R🜨
Mass4.02±0.68[3] ME
Mean density
6.88±1.18 g/cm3[3]
Temperature1039±26 K[4] (equilibrium)

Kepler-93b (KOI-69b) is a hot, dense transiting Super-Earth exoplanet located approximately 314 light-years (96.18 parsecs)[2] away in the constellation of Lyra[5][6], orbiting the G-type star[5] Kepler-93. Its discovery was announced in February 2014 by American astronomer Geoffrey Marcy and his team[1]. At the time of discovery, it had the most precisely measured radius of any exoplanet with a mere 1.3% margin of error[7].

Physical properties[edit]

An artist's impression comparing the size and internal structure of Earth (left) and Kepler-93b (right).

The planet has a radius of around 1.478 R🜨 (9,416 km), with an uncertainty of just 0.019 R🜨 (121 km)[4], making it the most precisely measured exoplanet ever in terms of radius as of July 2014[7]. The planet is substantially denser than Earth at 6.88±1.18 g/cm3[3] thanks to its high mass of roughly 4 ME, consistent with a rocky composition of iron and magnesium silicate[3].

Based on these findings, the interior of the planet is likely similar to that of Earth and Venus, with an iron core making up around 26% of its total mass (albeit with a large uncertainty of ±20%)[8], compared to the 32.5 ± 0.1% of Earth and 31 ± 1% of Venus[8].

The planet orbits its host star every 4.73 days[4] at a distance of 0.053 AU (7,900,000 km)[3], less than one-seventh the radius of Mercury's orbit. Its equilibrium temperature is approximately 1,037 K (764 °C; 1,407 °F)[4], which is nearly as hot as lava and hot enough to melt aluminium.

Host star[edit]

The planet orbits a Sun-like (spectral type G5V)[5] star named Kepler-93. The star has a mass of 0.911 M☉ and a radius of 0.919 R☉. It has a temperature of 5,669 K (5,396 °C; 9,745 °F) and is 6.6 billion years old[4]. In comparison, the Sun is 4.6 billion years old[9], has a temperature of 5,772 K (5,499 °C; 9,930 °F) and a spectral type of G2V[10].

The star is host to an additional non-transiting confirmed companion, Kepler-93c, which was discovered using the radial-velocity method and announced in 2014, concurrently with Kepler-93b[1]. The object is most likely a super-Jupiter planet orbiting much farther out than Kepler-93b, though its precise nature remains uncertain: the discovery paper reported a minimum mass of 3 MJ and a minimal orbital period of 1,460 days (4.0 years)[1], while a subsequent study in 2015 weighed the planet at >8.5 MJ and presented an orbital period of >10 years, placing its orbit beyond 4.5 AU from the star[3].

See also[edit]

References[edit]

  1. ^ a b c d e Marcy, Geoffrey W.; et al. (February 2014). "Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets". The Astrophysical Journal Supplement Series. 210 (2): 20. arXiv:1401.4195. Bibcode:2014ApJS..210...20M. doi:10.1088/0067-0049/210/2/20. hdl:1721.1/92945. S2CID 10760418.
  2. ^ a b "The Extrasolar Planet Encyclopaedia — Kepler-93b". Extrasolar Planets Encyclopaedia. Retrieved 2024-05-04.
  3. ^ a b c d e f g h Dressing, Courtney D.; et al. (February 2015). "The Mass of Kepler-93b and The Composition of Terrestrial Planets". The Astrophysical Journal. 800 (2). arXiv:1412.8687. Bibcode:2015ApJ...800..135D. doi:10.1088/0004-637X/800/2/135. S2CID 53471038. 135.
  4. ^ a b c d e f g Ballard, Sarah; et al. (July 2014). "Kepler-93b: A Terrestrial World Measured to within 120 km, and a Test Case for a New Spitzer Observing Mode". The Astrophysical Journal. 790 (1). arXiv:1405.3659. Bibcode:2014ApJ...790...12B. doi:10.1088/0004-637X/790/1/12. S2CID 12644226. 12.
  5. ^ a b c "BD+38 3853". SIMBAD. Retrieved 2024-05-08.
  6. ^ "SKY-MAP.ORG - Interactive Sky Map". Sky-Map.org. Retrieved 2024-05-08.
  7. ^ a b "Gauging an Alien World's Size". NASA. 2014-07-22. Retrieved 2024-05-07.
  8. ^ a b Li, Zeng; et al. (March 2016). "Mass-Radius Relation for Rocky Planets based on PREM". The Astrophysical Journal. 819 (2). arXiv:1512.08827. Bibcode:2016ApJ...819..127Z. doi:10.3847/0004-637X/819/2/127. S2CID 119111854. 127.
  9. ^ Connelly, JN; Bizzarro, M; Krot, AN; Nordlund, Å; Wielandt, D; Ivanova, MA (2 November 2012). "The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk". Science. 338 (6107): 651–655. Bibcode:2012Sci...338..651C. doi:10.1126/science.1226919. PMID 23118187. S2CID 21965292.(registration required)
  10. ^ Williams, D.R. (1 July 2013). "Sun Fact Sheet". NASA Goddard Space Flight Center. Archived from the original on 2010-07-15. Retrieved 2013-08-12.


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