Etamine , also called Eltanin, Ethanine ( γ Dra / γ Dragon / Gamma Dragon) is the brightest star in the constellation Dragon .
| Ethamine | |||
|---|---|---|---|
| Star | |||
| Observational data ( Age J2000 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | 148 ± 3 St. years (45.2 ± 0.9 pc ) | ||
| Visible magnitude ( V ) | 2.24 | ||
| Constellation | The Dragon | ||
| Astrometry | |||
| Radial velocity ( R v ) | -28 km / s | ||
| Own movement (μ) | RA: -8.52 mas per year Dec: -23.05 mas per year | ||
| Parallax (π) | 22.10 ± 0.46 mas | ||
| Absolute magnitude (V) | -1.04 | ||
| Characteristics | |||
| Spectral class | K5 III | ||
| Color Index ( B - V ) | 1,52 | ||
| Color Index ( U - B ) | 1.87 | ||
| physical characteristics | |||
| Weight | 1,7 M ☉ | ||
| Radius | 50 R ☉ | ||
| Age | 3.14 × 10 8 years | ||
| Temperature | 4000 K | ||
| Luminosity | 600 L ☉ | ||
| Metallicity | -0.14 | ||
| Rotation | <17 km / s | ||
| |||
| Database Information | |||
| SIMBAD | |||
Ethamine is an orange giant of spectral class K5, located 148 light years from Earth, visual magnitude - 2.24 m . The name means "dragon" in Arabic.
In 1.5 million years, Etamine will be the brightest star in the earth's sky and will have a visible brilliance comparable to Sirius at present. The minimum distance to Earth will be 28 light years.
Ethamine is an old star with a mass of about 1.7 solar and a luminosity of 600 solar. The diameter of Etamin is approximately 50 times larger than the sun.
In 1728, the English astronomer James Bradley , trying to measure the parallax of this star, discovered the phenomenon of light aberration . This discovery confirmed the theory of Copernicus that the Earth revolves around the Sun [2] .
In Ursula Le Guin 's science fiction novel Planet of Exile , the action takes place on the 3rd planet of the Gamma Dragon system.
See also
- Eltanina Antenna
Notes
- ↑ 1 2 3 4 Leeuwen F. v. Validation of the new Hipparcos reduction // Astron. Astrophys. - EDP Sciences , 2007. - Vol. 474, Iss. 2. - P. 653–664. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361: 20078357 - arXiv: 0708.1752
- ↑ Kaler, James B. ELTANIN (Gamma Draconis) (Link not available) . Stars University of Illinois. Date of treatment November 21, 2010. Archived July 21, 2010.