Delta Pavonis
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| Observation data Epoch J2000 |
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|---|---|
| Constellation (pronunciation) |
Pavo |
| Right ascension | 20h 08m 43.6084s[1] |
| Declination | −66° 10′ 55.446″[1] |
| Apparent magnitude (V) | 3.56[1] |
| Characteristics | |
| Spectral type | G7IV[1] |
| U-B color index | 0.45[2] |
| B-V color index | 0.76[2] |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | -21.7±0.9[1] km/s |
| Proper motion (μ) | RA: 1210.50±0.58[1] mas/yr Dec.: −1130.27±0.44[1] mas/yr |
| Parallax (π) | 163.78 ± 0.65[1] mas |
| Distance | 19.91 ± 0.08 ly (6.11 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.62 |
| Details | |
| Mass | 0.98 ± 0.03 M☉ |
| Radius | 1.06 R☉ |
| Surface gravity (log g) | 3.8[3] |
| Luminosity | 1.18 L☉ |
| Temperature | 5560[3] K |
| Metallicity | 240% Sun |
| Rotation | 1 km/s (~54 days) |
| Age | 5–7 × 109[4] years |
| Other designations | |
|
HD 190248, HR 7665, CD-66°2367, GCTP 4754, GJ 780, LHS 485, SAO 254733, LTT 7946, LFT 1520, and HIP 99240.[1]
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Delta Pavonis (δ Pav / δ Pavonis) is a star about 19.9 light years away from Earth. It is in constellation Pavo.
Contents |
[edit] Observations
It is a dwarf star (or already a subgiant) of spectral type G7 V-IV, meaning it is about to stop fusing hydrogen in its core and is starting the process of becoming a red giant. Because of that, Delta Pavonis is slightly brighter than the Sun even though it is cooler. The age of this star is in the range of 5–7 Gyr, and the luminosity has increased 60% since it became a zero-age main sequence star. (The later increase is similar to the Sun.) The galactic orbit of Delta Pavonis is very similar to the Sun. No planetary companions have yet been discovered in orbit around this star.[4]
Spectroscopic examination of this star shows that it has a higher abundance of elements heavier than Helium (or metallicity, as astronomers call it) than does the Sun. This value is typically given in terms of the relative ratio of Iron to Hydrogen as compared to the Sun's atmosphere. (Iron being a relatively easy element to detect in a stellar atmosphere.) For Delta Pavonis, the metallicity is about:
![\begin{smallmatrix}\left [ \frac{Fe}{H} \right ]\ =\ 0.38\end{smallmatrix}](../../../../math/9/2/9/929eaea240c95be9b62ca64b41b637ef.png)
(This notation gives the logarithm of the Iron to Hydrogen ratio relative to the Sun.) This corresponds to a 240% abundance of Iron in this star's atmosphere compared to the solar abundance. Past studies have shown a correlation between the heavy element abundance in stars and the presence of a planetary system.[5]
[edit] SETI
It has been identified by Maggie Turnbull and Jill Tarter of the SETI Institute as the "Best SETI target" in a survey of nearby stars.[6] Delta Pavonis is the nearest sun-like star not a member of a binary or multiple star system.[4]
[edit] See also
[edit] References
- ^ a b c d e f g h i HD 190248 -- Variable Star. Centre de Données astronomiques de Strasbourg. Retrieved on 2008-01-17.
- ^ a b Cousins, A. W. J.; Stoy, R. H. (1962). "Photoelectric magnitudes and colours of Southern stars". Royal Observatory Bulletins 64: 103-248.
- ^ a b Abia, C.; Rebolo, R.; Beckman, J. E.; Crivellari, L. (1988). "Abundances of light metals and Ni in a sample of disc stars.". Astronomy & Astrophysics 206: 100-107.
- ^ a b c G. F. Porto de Mello, E. F. del Peloso, L. Ghezzi (2006). "Astrobiologically interesting stars within 10 parsecs of the Sun". Astrobiology 6 (2): 308-331. doi:.
- ^ S.G. Sousa, N.C. Santos, G. Israelian, M. Mayor, M. J. P. F. G. Monteiro (2006). "Spectroscopic parameters for a sample of metal-rich solar-type stars". Astronomy and Astrophysics 458 (3): 873-880. doi:.
- ^ M.C. Turnbull, J.C. Tarter (2003). "Target Selection for SETI. II. Tycho-2 Dwarfs, Old Open Clusters, and the Nearest 100 Stars". The Astrophysical Journal Supplement Series 149 (2): 423-436.
[edit] External links
- Delta Pavonis. SolStation. Retrieved on November 3, 2005.
