18 Scorpii
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| Observation data Equinox J2000.0 |
|
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 15m 37s |
| Declination | -08° 22' 06" |
| Apparent magnitude (V) | 5.50 |
| Characteristics | |
| Spectral type | G1V |
| U-B color index | 0.18 |
| B-V color index | +0.64 |
| Variable type | No |
| Astrometry | |
| Radial velocity (Rv) | 11 km/s |
| Proper motion (μ) | RA: -496 mas/yr Dec.: 232 mas/yr |
| Parallax (π) | 71.30 ± 0.89 mas |
| Distance | 45.7 ± 0.6 ly (14 ± 0.2 pc) |
| Absolute magnitude (MV) | 4.77 |
| Details | |
| Mass | 1.01 ± 0.03 M☉ |
| Radius | 1.02–1.03 R☉ |
| Luminosity | 1.08 L☉ |
| Temperature | 5800 K |
| Metallicity | 105-112% |
| Rotation | 23 days |
| Age | 4.2 × 109 years |
| Other designations | |
18 Scorpii is a star located some 45.7 light years from earth at the northern edge of the Scorpius constellation.
18 Scorpii has many physical properties in common with the Sun and is regarded by some astronomers as the nearest solar twin. Due to this fact some scientists believe that the prospects for life in its vicinity are good.
Contents |
[edit] Star characteristics
18 Scorpii is a yellow main sequence dwarf star of spectral and luminosity type G1-5 V-Va. Its metallicity is about 1.05 to 1.12 that of the Sun.[1][2]
According to Lookwood, 2002,[3] it has a temporal photometric behavior very similar to the Sun however, according to Lookwood, 2000,[4] the activity cycle of 18 Scorpii may be of greater amplitude than the Sun's and that its overall chromospheric activity level is noticeably greater than the Sun's. This excellent solar photometric twin therefore may be a less perfect spectroscopic twin.
18 Scorpii is a solitary star. It is unknown at the moment whether it has planets.
[edit] Prospects for life
18 Scorpii was identified in September 2003 by astrobiologist Margaret Turnbull from the University of Arizona in Tucson as one of the most promising nearby candidates for hosting life based on her analysis of the HabCat list of stars.
[edit] See also
- List of stars
- List of nearest stars
- 37 Geminorum
- Planetary habitability
- Solar twin
- Space colonization
- HD 98618
[edit] References
- ^ Porto de Mello and da Silva (1997). "HR 6060: The Closest Ever Solar Twin?". The Astrophysical Journal 482 (2): L89–L92. DOI:10.1086/310693 .
- ^ Cayrel de Strobel et al, 1991.
- ^ G. W. Lockwood et al (May 2002). "Gauging the Sun: Comparative photometric and magnetic activity measurements of sunlike stars, 1984-2001" (PDF). Bulletin of the American Astronomical Society 34: 651.
- ^ Jeffrey C. Hall and G. W. Lockwood (2000). "Evidence of a Pronounced Activity Cycle in the Solar Twin 18 Scorpii". The Astrophysical Journal 545 (2): L43–L45. DOI:10.1086/317331.
