HR 8799
| Data Epoch J2000 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 23h 07m 28.7150s [1] |
| Declination | + 21°08′03.302″[1] |
| Apparent magnitude (V) | 5.964[1] |
| Characteristic | |
| Spectral class | A5V[1] |
| Color index (B-V) | 0.234[1] |
| Color index (U-B) | −0.04[2] |
| Variable star type | Gamma Doradus[1] |
| アストロメトリー | |
| Radial velocity (Rv) | −11.5 +-2 [1] km/s |
| Proper motion (μ) | Right ascension: 107.88[1]millisecond / year Declination: -50.08[1]millisecond / year |
| Annual parallax (π) | 25.38 [3] +-0.70[3]millisecond |
| Distance | 129 ± 4 Light-year （39 ± 1 Parsec） |
| Absolute magnitude (MV) | 3.0[4] |
| The details | |
| Mass | ~1.5 +-0.3 [5] M☉ |
| Radius | ~1.6[6] R☉ |
| Quantity of metal | −0.47 [Fe/H][5] |
| Rotation speed | 45 [2] km/s |
| Age | 60 million [5] years |
| Other names | |
I belong to Pegasus, and HR 8799 is the Dorado gamma type variable star that there is to distance of 129 light-year (39 parsecs) from the solar system. The name HR 8799 is an identifier in the Harvard revision intensity of light catalogue.
| The sun | HR 8799 |
|---|---|
 |  |
Table of contents
Planetary system
Four extrasolar planets are known to HR 8799 by 2010. These photographed the light of the planet directly and were discovered. As for the distance from the planet to the fixed star, the mass is estimated all to be around 5-10 times of the Jupiter each in 15AU, 24AU, 38AU, 68AU. In addition, there is a lot of small dust in planetary system, and it is thought that a process sprinkled a rose on dust by the collision between the primitive heavenly bodies progresses [7]. The planetary system is estimated to be young planetary system made only for approximately 60 million years by birth.
Observation
In November, 2008, Christian Maloy of the Hz Bergh astrophysics research institute and his team announced the thing that observed directly in orbit on three planets of the fixed star using Hawaiian W M ケック astronomical observatory and Gemini north telescope [8]; [9] [10].
After analyzing an image of HR 8799 photographed with the Hubble Space Telescope in 1998 using a latest processing technology in April, 2009, it was confirmed that outside planet b came out [11]. In May of the year, it was confirmed that planet b appeared in the image photographed with Subaru telescope in 2002 [12].
The disk of the dust similar to the edge Worth Kuiper's comet belt of the solar system exists immediately outside planet b. As for this, there is room to be able to exist a terrestrial planet inside of the star system in one of the largest things that there is it to less than 300 light-year from the earth [9].
In January, 2010, the European nandin astronomical observatory announced the observation result of HR 8799 c where I used a supersized telescope for. By this observation, the light that an extrasolar planet emitted was dismantled in direct form for the first time in the world by a spectrum [note 1]; [13].
In December, 2010, existence of the fourth planet HR 8799 e was announced [14]. As well as three other planets, I was discovered by a method by the direct photography [14]. In addition, the possibility with the asteroid belt is shown immediately inside orbit, too [14].
| Name (order near the fixed star) | Mass | Orbit semimajor axis （Au） | Revolution period (Year) | Orbit eccentricity | Orbit angle of inclination | Radius |
|---|---|---|---|---|---|---|
| Asteroid belt (estimate) | ? AU | |||||
| e | 9±4 MJ | ~ 14.5+-0.5 | ~ 50 | — | — | — |
| d | 10±3 MJ | ~ 24 | ~ 100 | > 0.04 | — | — |
| c | 10±3 MJ | ~ 38 | ~ 190 | — | — | — |
| b | 7+4 −2 MJ | ~ 68 | ~ 460 | — | — | — |
| Disk of the dust | 75 AU | |||||
Footnote
- I straighten ^, and there is the precedent that the spectrum of the heavenly bodies where it is unknown whether it is an example and a planet or the brown dwarf where a spectrum was measured as dimming indirectly when a planet is covered on the fixed star was arrested.
References
- ^ a b c d e f g h i j V* V342 Peg - - Variable Star of gamma Dor type, entry, SIMBAD. It is 2008 in 14 in Accessed on line November.
- ^ a b HR 8799, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. It is 2008 in 14 in Accessed on line November.
- ^ a b van Leeuwen, F. (2007). "HIP 114189". Hipparcos, the New Reduction. October 13, 2008 reading.
- ^ From apparent magnitude and parallax.
- ^ a b c Schneider, J.. "Notes for star HR 8799". The Extrasolar Planets Encyclopaedia. October 13, 2008 reading.
- ^ HD 218396, database entry, Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS), 3rd edition, L. E. Pasinetti-Fracassini, L. Pastori, S. Covino, and A. Pozzi, CDS ID II/224. It is 2008 in 14 in Accessed on line November.
- ^ "Small, Ground-Based Telescope Images Three Exoplanets." NASA JPL. (April 14, 2010)8 April 22, 2010 reading.
- ^ Marois, Christian; et al. (November 2008). "Direct Imaging of Multiple Planets Orbiting the Star HR 8799". Science Forthcoming. doi: 10.1126/science.1166581 November 13, 2008 reading. . (Preprint at exoplanet.eu)
- ^ a b "Astronomers capture first images of newly-discovered solar system" (press release), W. M. Keck Observatory, (November 13, 2008)1 November 13, 2008 reading.
- ^ Achenbach, Joel (November 13, 2008). "Scientists Publish First Direct Images of Extrasolar Planets". The Washington Post (The Washington Post Company)l November 13, 2008 reading.
- ^ "old Hubble image a planet discovery." National Geographic (April 3, 2009). February 14, 2011 reading.
- ^ "Subaru, the photography of the system superior planet success." National Astronomical Observatory Hawaii observatory (May 21, 2009). May 27, 2009 reading.
- ^ "VLT Captures First Direct Spectrum of an Exoplanet." ESO. (January 13, 2010)/ January 14, 2010 reading.
- ^ a b c "The fourth planet which is heterogeneous in system superior planet system". National Geographic. (December 9, 2010)/ June 13, 2016 reading.
This article is taken from the Japanese Wikipedia HR 8799
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