HD 219134 b
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Exoplanet HD 219134 b |
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| Artist's impression of the possible appearance of HD 219134 b with a rocky and partially melted surface | |
| Constellation | Cassiopeia |
| Position equinox : J2000.0 |
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| Right ascension | 23h 13m 16.97632s |
| declination | + 5710 ° 06.0823 ′ |
| Orbit data | |
| Central star | HR 8832 |
| Major semi-axis | 0.03876 ± 0.00047 AU |
| eccentricity | 0 |
| Period of circulation | 3.092926 ± 0.000010 d |
| Further data | |
| radius | 1.602 ± 0.055 R ♁ |
| Dimensions | 4.74 ± 0.19 M ♁ |
| distance | 6.55 ± 0.01 pc |
| history | |
| discovery | F. Motalebi et al |
| Date of discovery | 2015 |
| Catalog names | |
| HD 219134 b, HR 8832 b | |
| More information | |
| Density estimated at 6.34 ± 0.72 g / cm 3 | |
HD 219134 b is an exoplanet that the approximately 21 light-years from the sun distant main sequence star 8832 HR (also 219134 HD ) in the constellation Cassiopeia circles. It is the innermost of up to six known planets in the star's planetary system .
discovery
The planet was detected together with three others initially as part of the Rocky Planet Search program with the HARPS-N spectrograph at the Telescopio Nazionale Galileo on La Palma through precise measurements of the star's radial velocity over a period of three years. Due to the planet's orbit near the star, there was a certain probability that HD 219134 b would pass in front of its central star.
With the Spitzer Space Telescope of NASA then the additional proof was obtained by measurements April 2015 actually the planet by the transit method . The team of astronomers around Fatemeh Motalebi from the Geneva observatory announced the discovery of HD 219134 b and the three other planets of HR 8832 on July 30, 2015. HD 219134 b is the exoplanet closest to the Sun that has been detected using the transit method.
A second team of astronomers led by Steven S. Vogt was also able to detect the planet independently using the radial velocity method , based on observations made with the HIRES spectograph at the Keck Observatory in Hawaii and the Automated Planet Finder at the Lick Observatory .
properties
HD 219134 b orbits its central star at a very short distance and only needs about three days for one orbit. According to model calculations based on the radial velocity measurements, its minimum mass is around 4.74 earth masses . The radius of the planet could be determined by the transit observations to be approximately 1.6 earth radii . The values for mass and radius initially resulted in an estimate of the density of around 5.89 g / cm 3 , which means that HD 219134 b must be a rocky planet . Research by a team of astronomers led by Michael Gillon suggests a 1.15 times density of the earth. The model calculation of the second team of explorers around Vogt came to an approximately the same value for the orbital time, but a lower minimum mass of around 3.8 earth masses.
The planet belongs to the class of super-earths and is far too close to its star for conditions to be favorable to life. Its surface is likely to have temperatures similar to those on Venus in the solar system . Due to the high temperatures and the gravitational effects of the nearby star, the surface of HD 219134 b may be shaped by volcanoes and lava .
Due to the fact that HD 219134 b passes in front of HR 8832 when viewed from Earth (which offers the possibility of detecting and exploring an atmosphere) and its relative proximity to Earth, the planet is an interesting research object. In the press release the Jet Propulsion Laboratory of NASA during his discovery of HD 219134 b was even called "a kind of Rosetta stone for studying super-Earths" means (a kind of Rosetta Stone for the study of super-Earths).
In 2017 it could be proven that the next outer planet HD 219134 c also moves past its central star from Earth.
Individual evidence
- ↑ SIMBAD: HR 8832. Accessed August 2, 2015 .
- ↑ a b c d e f g h Michael Gillon et al .: Two massive rocky planets transiting a K-dwarf 6.5 parsecs away . arxiv : 1703.01430 .
- ↑ a b c d e NASA Exoplanet Archive: Planet HD 219134 b. Retrieved February 13, 2018 .
- ↑ a b c Steven S. Vogt et al: A Six-Planet System Orbiting HD 219134 . arxiv : 1509.07912 .
- ↑ a b c d e f F. Motalebi include: The HARPS-N Rocky Planet Search I. HD219134b: A rocky planet transiting in a multi-planet system at 6.5 pc from the Sun . arxiv : 1507.08532 .
- ↑ a b c d Jet Propulsion Laboratory: NASA's Spitzer Confirms Closest Rocky Exoplanet. Retrieved August 2, 2015 .
- ↑ a b c d Stars and Space from July 31, 2015: Our closest distant neighbor in space . Retrieved August 2, 2015 .