Eta2 Hydri
From Wikipedia, the free encyclopedia
- The correct title of this article is Eta2 Hydri. It features superscript or subscript characters that are substituted or omitted because of technical limitations.
| Observation data Epoch J2000.0 |
|
|---|---|
| Constellation | Hydrus |
| Right ascension | 01h 54m 56m |
| Declination | -67° 38' 50" |
| Apparent magnitude (V) | +4.7 |
| Characteristics | |
| Spectral type | G8.5III |
| B-V color index | ? |
| U-B color index | ? |
| Variable type | none |
| Astrometry | |
| Radial velocity (Rv) | -16.2 km/s |
| Proper motion (μ) | RA: 76.00 mas/yr Dec.: 73.17 mas/yr |
| Parallax (π) | 15.04 ± .49 .40 1 mas |
| Distance | 216.89 ly (66.53 pc) |
| Absolute magnitude (MV) | ? |
| Details | |
| Mass | 1.91 M☉ |
| Radius | 10.09 R☉ |
| Luminosity | ? L☉ |
| Temperature | 4970 K |
| Metallicity | -0.21 [Fe/H] 0.61 |
| Rotation | 230 d |
| Age | 500 - 2000 Million years |
| Other designations | |
|
HD 11977, HR 570, HIP 8928....
|
|
Eta2 Hydri (η2 Hyi / η2 Hydri) is a yellow giant star approximately 216 light-years away in the constellation Hydrus. Based on its mass, it was probably a class A star (similar to Vega or Fomalhaut) when it was on the main sequence, though it is now in the giant stage of its evolution.
[edit] Eta² Hydri b
| Extrasolar planet | Lists of extrasolar planets | |
|---|---|---|
| Orbital elements | ||
| Semimajor axis | (a) | 1.93 AU |
| Eccentricity | (e) | 0.40±0.07 |
| Orbital period | (P) | 711±8 d |
| Inclination | (i) | ?° |
| Longitude of periastron |
(ω) | 351.5±9.5° |
| Time of periastron | (τ) | 2,451,420 JD |
| Physical characteristics | ||
| Mass | (m) | >6.54 MJ |
| Radius | (r) | ? RJ |
| Density | (ρ) | ? kg/m3 |
| Temperature | (T) | ? K |
| Discovery information | ||
| Discovery date | 2005 | |
| Discoverer(s) | Hatzes et al. | |
| Detection method | Radial velocity | |
| Discovery status | Confirmed | |
Eta2 Hydri b (also known as HD 11977 b) is an extrasolar planet orbiting Eta2 Hydri. The presence of the planet around an intermediate-mass giant star provides indirect evidence for the existence of planetary systems around A-type stars.
[edit] References
- Setiawan, J., Rodmann, J., da Silva, L., Hatzes, A., Pasquini, L., von der Lühe, O., de Medeiros, J., Döllinger, M., Girardi, L. (2005). "A substellar companion around the intermediate-mass giant star HD 11977". Astronomy & Astrophysics 437: L31 – L34.
[edit] External links
 |
This star-related article is a stub. You can help Wikipedia by expanding it. |
 |
This extrasolar planet related article is a stub. You can help Wikipedia by expanding it. |
