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[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.
References
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- 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
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- ↑ 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.