Astronomy:Upsilon1 Eridani
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Short description: Red clump star in the constellation Eridanus
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 33m 30.55236s[1] |
| Declination | −29° 45′ 59.3725″[1] |
| Apparent magnitude (V) | 4.51[2] |
| Characteristics | |
| Spectral type | K0 III-IV[3] |
| U−B color index | +0.70[2] |
| B−V color index | +0.98[2] |
| Astrometry | |
| Radial velocity (Rv) | +20.89±0.69[4] km/s |
| Proper motion (μ) | RA: −114.78[1] mas/yr Dec.: −271.79[1] mas/yr |
| Parallax (π) | 25.67 ± 0.24[1] mas |
| Distance | 127 ± 1 ly (39.0 ± 0.4 pc) |
| Absolute magnitude (MV) | 1.60[4] |
| Details | |
| Mass | 1.54[4] M☉ |
| Radius | 7.3[5] R☉ |
| Luminosity | 24[4] L☉ |
| Surface gravity (log g) | 3.09[4] cgs |
| Temperature | 4,941[4] K |
| Metallicity [Fe/H] | −0.16±0.08[4] dex |
| Rotational velocity (v sin i) | 2.15[6] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Upsilon1 Eridani (υ1 Eri) is a single star in the constellation Eridanus. It has an apparent visual magnitude is 4.51,[2] which is bright enough to be faintly visible to the naked eye on a clear, dark night. The distance to this star, as determined using the parallax method,[1] is around 127 light years.
This is an evolved red clump[8] giant star with a stellar classification of K0III-IV.[3] The measured angular diameter, after correction for limb darkening, is 1.74±0.02 mas.[9] At an estimated distance of this star, this yields a physical size of about 7.3 times the radius of the Sun.[5] It has 154%[4] of the Sun's mass and radiates 24 times the solar luminosity from its outer atmosphere at an effective temperature of 4,941 K.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Luck, R. Earle; Heiter, Ulrike (June 2007), "Giants in the Local Region", The Astronomical Journal 133 (6): 2464–2486, doi:10.1086/513194, Bibcode: 2007AJ....133.2464L.
- ↑ 5.0 5.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41. The radius (R*) is given by:
- [math]\displaystyle{ \begin{align} 2\cdot R_* & = \frac{(39.0\cdot 1.74\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 14.6\cdot R_{\bigodot} \end{align} }[/math]
- ↑ Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics 475 (3): 1003. doi:10.1051/0004-6361:20078233. Bibcode: 2007A&A...475.1003H.
- ↑ "* ups01 Eri". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+ups01+Eri.
- ↑ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal 539 (2): 732–741, doi:10.1086/309278, Bibcode: 2000ApJ...539..732A.
- ↑ Richichi, A. et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R.
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