HD 98618
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 11h 21m 29s |
| Declination | +58° 53′ 18″ |
| Apparent magnitude (V) | 7.66 |
| Characteristics | |
| Spectral type | G5V |
| U−B color index | ? |
| B−V color index | 0.642 |
| Variable type | none |
| Astrometry | |
| Radial velocity (Rv) | 16 km/s |
| Proper motion (μ) | RA: 41.28 mas/yr Dec.: 29.19 mas/yr |
| Parallax (π) | 25.82 ± 0.86 mas |
| Distance | 126 ly (38.7 pc) |
| Absolute magnitude (MV) | 4.74 ± 0.07 |
| Details | |
| Mass | 1.02±0.03 M☉ |
| Radius | 1.00 R☉ |
| Luminosity | 1.06 ± 0.05 L☉ |
| Temperature | 5843 ± 30 K |
| Metallicity | 1.05 sol |
| Rotation | 24 days |
| Age | 4210 ± 900 million years |
| Other designations | |
Coordinates: 
11h 21m 29s, +58° 53′ 18″
HD 98618 is a star 126 light years from Earth that is almost identical in most respects to the Sun; it has therefore been proposed as a candidate solar twin.[1] However, like the solar twin 18 Scorpii, HD 98618 has a lithium abundance significantly higher than that of the Sun ([Li/H] = +0.45 ± 0.08).[2] Meléndez & Ramírez (2007) have suggested that HD 98618 be considered a "quasi solar twin", since they have now identified a solar twin, HIP 56948, with lithium content identical within the observational error to the Sun's.
References
- ↑ Meléndez, J., & Dodds-Eden, K., & Robles, J. A. (2006). "HD 98618: A Star Closely Resembling Our Sun". The Astrophysical Journal 641 (2): L133–L136. arXiv:astro-ph/0603219. Bibcode:2006ApJ...641L.133M. doi:10.1086/503898.
- ↑ Meléndez, J., & Ramírez, I. (2007). "HIP 56948: A Solar Twin with a Low Lithium Abundance". The Astrophysical Journal 669 (2): L89–L92. arXiv:0709.4290. Bibcode:2007ApJ...669L..89M. doi:10.1086/523942.
External links
| ||||||||||||||||||||||||||||||||||
This article is issued from Wikipedia - version of the Friday, January 02, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.