Eta Corvi
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Corvus |
| Right ascension | 12h 32m 04.2270s[1] |
| Declination | −16° 11′ 45.627″[1] |
| Apparent magnitude (V) | 4.31[1] |
| Characteristics | |
| Spectral type | F2 V[1] |
| U-B color index | +0.00[1] |
| B-V color index | +0.38[1] |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | -3.5[1] km/s |
| Proper motion (μ) | RA: -424.37[1] mas/yr Dec.: -58.41[1] mas/yr |
| Parallax (π) | 54.92 ± 0.66[1] mas |
| Distance | 59.4 ± 0.7 ly (18.2 ± 0.2 pc) |
| Details | |
| Mass | 1.43 ± 0.05[2] M☉ |
| Temperature | 6,840[2] K |
| Metallicity | [Fe/H] = -0.05[2] |
| Rotation | 68 ± 2 km/s |
| Age | 1.3 ± 0.6 × 109[2] years |
| Other designations | |
Eta Corvi (η Crv / η Corvi) is a yellow-white main sequence star in the constellation Corvus. Orbiting this star is a debris disk.[3]
[edit] Properties
This star is about 40% more massive than the Sun but is only about 30% of the Sun's age. Compared to the Sun, it has only 90% of the isotopes heavier than Helium.[2] The projected rotational velocity at the equator (vsini) is a brisk 68 km/s.[4]
The IRAS satellite detected an excess of infrared radiation from this star, beyond what would normally be expected for a stellar object of this class.[5] Observations in the submillimetre band confirmed the presence of excess dust in orbit around the star having about 60% of the mass of the Moon and a temperature of 80 K. The data indicated a debris disk with an estimated maximum radius of 180 A.U. from the star, or 180 times the separation of the Earth and the Sun.[6] (Compare to the Kuiper belt, which extends out to 55 A.U. from the Sun.)
Recent observations have been able to resolved some components of the disk. The debris is arranged in a flat, circumstellar disk with an outer radius of 150 A.U. It is oriented at an inclination to the line of sight from the Earth. Most of the inner 100 A.U. of the disk is relatively free of material, which suggests it was cleared away by a planetary system. However, there is some evidence of a separate component with a temperature that would indicate a radius of 1–2 A.U., but this remains to be confirmed.[3]
Due to the estimated age of this star, the observed circumstellar disk was created following the formation of the system. The Poynting-Robertson effect would have caused the dust in the current disk to spiral in to the star within 20 million years. So it is more likely that the disk was created through collisions of larger objects at a distance of about 150 A.U.[3]
[edit] References
- ^ a b c d e f g h i j SIMBAD query result: NSV 5690 -- Variable Star. Centre de Données astronomiques de Strasbourg. Retrieved on 2007-07-17.
- ^ a b c d e Nordström, B.; Mayor, M.; Andersen, J.; Holmberg, J.; Pont, F.; Jørgensen, B. R.; Olsen, E. H.; Udry, S.; Mowlavi, N. (2004). "The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities and kinematic properties of ~14,000 F and G dwarfs". Astronomy & Astrophysics 418: 989–1019. doi:.
See: VizieR Detailed Page: record #8509. VizieR Service at Centre de Données astronomiques de Strasbourg. - ^ a b c Wyatt, M. C.; Greaves, J. S.; Dent, W. R. F.; Coulson, I. M. (2005). "Submillimeter Images of a Dusty Kuiper Belt around η Corvi" ([dead link] – Scholar search). The Astrophysical Journal 620: 492–500. doi:.
- ^ A. Mora et al (2001). "EXPORT: Spectral classification and projected rotational velocities of Vega-type and pre-main sequence stars". Astronomy & Astrophysics 378: 116–131. doi:.
- ^ Stencel, Robert E.; Backman, Dana E. (1991). "A survey for infrared excesses among high galactic latitude SAO stars". Astrophysical Journal Supplement Series 75: 905–924. doi:.
- ^ Sheret, I.; Dent, W. R. F.; Wyatt, M. C. (2004). "Submillimetre observations and modelling of Vega-type stars". Monthly Notices of the Royal Astronomical Society 348 (4): 1282–1294. doi:.
