Tau Bootis b

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Exoplanet
Tau Bootis b
Constellation Bear keeper
Position
equinox : J2000.0
Right ascension 13h 47m 15.743s
declination + 17 ° 27 ′ 24.86 ″
Orbit data
Central star Tau Bootis A
Major semi-axis 0.049 ± 0.003 AU
eccentricity 0.011 ± 0.006
Period of circulation 3.3124568 ± 0.0000069 d
Further data
Minimum dimensions 4.32 ± 0.04 M J
distance 15.6 ± 0.2 pc
history
discovery Marcy et al.
Date of discovery 1996

τ Bootis b ( Tau Bootis b , occasionally also Tau Bootis Ab ) is an exoplanet orbiting the star Tau Bootis A in the binary star system Tau Bootis in the constellation Bear Guardian.

discovery

Tau Bootis b was discovered in 1996 using the radial velocity method and is one of the first known exoplanets around a sun-like main sequence star . The discovery was published by Geoffrey Marcy , R. Paul Butler , and three other astronomers along with the planets 55 Cancri b and Ypsilon Andromedae b in 1997. In 1999 British scientists announced a direct observation of the planet with the William Herschel Telescope on La Palma , whereupon Tau Bootis b received the unofficial nickname Millennium Planet . However, this could later be refuted.

properties

Tau Bootis b belongs to the planetary class of the Hot Jupiters , which, as gas giants, orbit their central star at a very short distance. One orbit of the planet around Tau Bootis A only takes about 3.31 days with a major semi-axis of only about 0.049 AU . The orbital eccentricity is very small and is about 0.011.

The minimum mass of Tau Bootis b is around 4.32 masses of Jupiter . However, a study from 2012 assumes an actual mass of around 5.95 Jupiter's masses, with the planet's orbital inclination of around 44.5 °.

The albedo of the planet must be less than 0.37, as no reflected light has yet been detected. The temperature on the surface is at least 1,500 Kelvin. This extremely high temperature suggests that clouds of silicates could form over an atmosphere characterized by vapors from alkali metals, but these hypotheses are speculative and currently not verifiable.

Individual evidence

  1. ↑ VizieR: HIP 67047. Retrieved May 11, 2015 .
  2. ↑ a b c d NASA Exoplanet Archives: tau Boo b. Retrieved May 11, 2015 .
  3. ^ Butler, R. Paul et al .: Three New "51 Pegasi-Type" Planets . bibcode : 1997ApJ ... 474L.115B .
  4. ↑ The Independent of December 16, 1999: Scientists catch the `millennium 'planet's glow. Retrieved May 11, 2015 .
  5. ↑ a b Leigh, Christopher et al .: A new upper limit on the reflected starlight from τ Bootis b. Retrieved May 11, 2015 .
  6. ↑ a b c Borsa, F .; Scandariato, G .; Rainer, M. et al .: The GAPS Program with HARPS-N at TNG. VII. Putting exoplanets in the stellar context: magnetic activity and Asteroseismology of τ Bootis A . arxiv : 1504.00491 .
  7. ↑ Brogi, Matteo; Snellen, Ignas AG; de Kok, Remco J .; Albrecht, Simon; Birkby, Jayne; de Mooij, Ernst JW: The signature of orbital motion from the dayside of the planet tau Bootis b . arxiv : 1206.6109 .
  8. ↑ Lucas, PW et al .: Planetpol polarimetry of the exoplanet systems 55 Cnc and τ Boo. Retrieved May 11, 2015 .