HD 139357 is a star located in the constellation Dragon at a distance of about 396 light years from us. It has at least one planet .
| HD 139357 | |||
|---|---|---|---|
| Star | |||
| Observational data ( Age J2000.0 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | 400 ± 30 St. years (121 ± 8 pc ) | ||
| Visible magnitude ( V ) | 6.03 | ||
| Constellation | The Dragon | ||
| Astrometry | |||
| Radial velocity ( R v ) | -8.75 km / s | ||
| Own movement (μ) | RA: -17.96 mas per year Dec: 2,08 mas per year | ||
| Parallax (π) | 8.24 ± 0.54 mas | ||
| Absolute magnitude (V) | 7.03 | ||
| Specifications | |||
| Spectral class | K4III | ||
| Color Index ( B - V ) | 1,191 | ||
| physical characteristics | |||
| Weight | 1.35 ± 0.24 M ☉ | ||
| Radius | 11.47 ± 0.75 R ☉ | ||
| Age | 3.07 ± 1.47 Ga | ||
| Temperature | 4700 ± 70 K | ||
| Luminosity | 57,4 L ☉ | ||
| Metallicity | –0.13 ± 0.05 | ||
| |||
| Database Information | |||
| SIMBAD | data | ||
Content
Star
The star is a red giant : its mass is 1.35 of the mass of the Sun , and its radius is 11.4 of the solar. The surface temperature is 4700 degrees Kelvin . Her age is estimated at 3-4 billion years. [2] Under good weather conditions, the star can be observed with the naked eye.
Planet System
A group of German and Italian astronomers, over the course of three years observing a portion of the sky in the constellation Dragon, discovered two planets: HD 139357 b for this star and a planet in the 42 Dragon system. HD 139357 b is much larger than Jupiter and is 9 times more massive. It revolves around the parent star at a distance of 2.36 a. e. and makes a complete revolution in 1125 days. [2] It is interesting that both of these planets fit into the pattern for planets of medium-mass stars: they circulate in wide orbits and have a large mass.
| Planet | Weight ( M J ) | Radius ( R J ) | Circulation period ( days ) | Semimajor axis orbits ( a.u. ) | Eccentricity orbits |
|---|---|---|---|---|---|
| b | > 9.76 ± 2.15 | ? | 1125.7 ± 9 | 2.36 ± 0.2 | 0.1 ± 0.02 |
Notes
- ↑ 1 2 3 4 Gaia Data Release 2 - 2018.
- ↑ 1 2 MP Doellinger, AP Hatzes, L. Pasquini, EW Guenther, M. Hartmann, L. Girardi. Planetary companion candidates around the K giant stars 42 Dra and HD 139357 . arxiv.org (Mar 20, 2009). Date of treatment June 30, 2009.
See also
- Dragon constellation star list
- List of exoplanets discovered in 2009