Delta Eridani
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 43m 14.90s[1] |
| Declination | –09° 45′ 48.2″[1] |
| Apparent magnitude (V) | 3.54 |
| Characteristics | |
| Spectral type | K0 IV |
| U−B color index | 0.69 |
| B−V color index | 0.92 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | –6 km/s |
| Proper motion (μ) | RA: –93.16 ± 0.29[1] mas/yr Dec.: +743.64 ± 0.22[1] mas/yr |
| Parallax (π) | 110.61 ± 0.29[1] mas |
| Distance | 29.49 ± 0.08 ly (9.04 ± 0.02 pc) |
| Absolute magnitude (MV) | 3.77[2] |
| Details | |
| Mass | 1.33 ± 0.07[3] M☉ |
| Radius | 2.327 ± 0.029[3] R☉ |
| Luminosity | 3.00 ± 0.12[3] L☉ |
| Surface gravity (log g) | 3.9[4] cgs |
| Temperature | 5,055[5] K |
| Metallicity [Fe/H] | 0.13[5] dex |
| Rotational velocity (v sin i) | 1.0[2] km/s |
| Other designations | |
Delta Eridani (δ Eri, δ Eridani) is a 3.54 magnitude star in the constellation of Eridanus. It is also called Rana. The name Rana means "the frog" in Latin. Rana was referenced as a guide star in "Sky Captain and the World of Tomorrow"[6]
In Chinese, 天苑 (Tiān Yuàn), meaning Celestial Meadows, refers to an asterism consisting of δ Eridani, γ Eridani, π Eridani, ε Eridani, ζ Eridani, η Eridani, π Ceti, τ1 Eridani, τ2 Eridani, τ3 Eridani, τ4 Eridani, τ5 Eridani, τ6 Eridani, τ7 Eridani, τ8 Eridani and τ9 Eridani.[7] Consequently, δ Eridani itself is known as 天苑三 (Tiān Yuàn sān, English: the Third Star of Celestial Meadows.)[8]
Structure
This star is relatively near to the Sun, at a measured distance of about 29 light years. It is sometime listed as a RS Canum Venaticorum-type variable star, but this is likely to be an error. (It is currently a suspected variable.) Rana is a sub-giant star that is near the end of its hydrogen-burning cycle and is now consuming helium. This has caused the star to expand and become hotter than a comparable main sequence star. As a sub-giant star it is subject to pulsations in its atmosphere.
Radial velocity surveys of this star have thus far failed to discern any gas giants in orbit.
See also
References
- 1 2 3 4 5 van Leeuwen, F. (2007). "HIP 17378". Hipparcos, the New Reduction. Retrieved 2009-12-11.
- 1 2 Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics, 361: 614–628, Bibcode:2000A&A...361..614P
- 1 2 3 Bruntt, H.; et al. (July 2010), "Accurate fundamental parameters for 23 bright solar-type stars", Monthly Notices of the Royal Astronomical Society, 405 (3): 1907–1923, arXiv:1002.4268
, Bibcode:2010MNRAS.405.1907B, doi:10.1111/j.1365-2966.2010.16575.x - ↑ Morell, O.; Kallander, D.; Butcher, H. R (1999). "The age of the Galaxy from thorium in G dwarfs, a re-analysis". Astronomy and Astrophysics. 259 (2): 543–548. Bibcode:1992A&A...259..543M.
- 1 2 Piau, L.; et al. (February 2011), "Surface convection and red-giant radius measurements", Astronomy and Astrophysics, 526: A100, arXiv:1010.3649, Bibcode:2011A&A...526A.100P, doi:10.1051/0004-6361/201014442
- ↑ Constellations of Words - Eridanus (Rana)
- ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ↑ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
Sources
- Fisher, G. F., Hall, D. S., Henry, G. W., Landis, H. J., Renner, T. R., and Shore, S. N., "Delta Eridani: A Very Bright New Variable Star,", Information Bulletin on Variable Stars, No. 2259, 1983.
- Eaton, J. A.; Poe, C. H., "Limits on the Variability of epsilon Eridani and delta Eridani", Information Bulletin on Variable Stars, 2712, 1985.
External links
- Jim Kaler's page on Rana
- SolStation entry
- nStars entry