| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 05 06 45.65314 |
| Declination | −04° 39′ 18.5939″ |
| Apparent magnitude (V) | 5.12 |
| Characteristics | |
| Spectral type | B9V |
| U−B color index | -0.16 |
| B−V color index | -0.06 |
| Variable type | α CVn |
| Astrometry | |
| Radial velocity (Rv) | 32.28 ± 0.10 km/s |
| Proper motion (μ) | RA: 10.70 mas/yr Dec.: -0.78 mas/yr |
| Parallax (π) | 10.56 ± 0.34 mas |
| Distance | 309 ± 10 ly (95 ± 3 pc) |
| Absolute magnitude (MV) | 0.37 |
| Orbit | |
| Period (P) | 5.5226013 ± 0.0000020 d |
| Eccentricity (e) | 0.0844 ± 0.0013 |
| Periastron epoch (T) | 2441356.499 ± 0.017 |
| Argument of periastron (ω) (secondary) | 160.9 ± 1.1° |
| Semi-amplitude (K1) (primary) | 102.83 ± 0.20 km/s |
| Semi-amplitude (K2) (secondary) | 100.35 ± 0.19 km/s |
| Details | |
| 66 Eri A | |
| Mass | 2.629 ± 0.032 M☉ |
| Radius | 1.948 ± 0.063 R☉ |
| Luminosity | 51.3 ± 3.3 L☉ |
| Surface gravity (log g) | 4.28 ± 0.03 cgs |
| Temperature | 11077 K |
| Rotational velocity (v sin i) | 17.1 ± 0.2 km/s |
| Age | 30 Myr |
| 66 Eri B | |
| Mass | 2.566 ± 0.032 M☉ |
| Radius | 1.919 ± 0.061 R☉ |
| Luminosity | 46.9 ± 3.0 L☉ |
| Surface gravity (log g) | 4.28 ± 0.03 cgs |
| Temperature | 10914 K |
| Rotational velocity (v sin i) | 16.9 ± 0.2 km/s |
| Other designations | |
| EN Eri, BD−04° 1044, HD 32964, HIP 23794, HR 1657, SAO 131777 | |
| Database references | |
| SIMBAD | data |
66 Eridani is a binary star in the constellation of Eridanus. The combined apparent magnitude of the system is 5.12 on average. Parallax measurements by Hipparcos put the system at some 309 light-years (95 parsecs) away.
This is a spectroscopic binary: the two stars cannot be individually resolved, but periodic Doppler shifts in its spectrum mean there must be orbital motion. The two stars orbit each other every 5.5226013 days. Their orbit is fairly eccentric, at 0.0844.
The combined spectrum of 66 Eridani matches that of a B-type main-sequence star, and the two stars have similar masses. The spectrum also shows excess of mercury and manganese, as it is a type of chemically peculiar star called a mercury-manganese star. 66 Eridani is an Alpha Canum Venaticorum variable. For this reason, it has been given the designation EN Eridani.
References
- ^ van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
- ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 5: 0. Bibcode:1999MSS...C05....0H.
- ^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ Makaganiuk, V.; Kochukhov, O.; Piskunov, N.; Jeffers, S. V.; Johns-Krull, C. M.; Keller, C. U.; Rodenhuis, M.; Snik, F.; Stempels, H. C.; Valenti, J. A. (2011). "Chemical spots in the absence of magnetic field in the binary Hg Mn star 66 Eridani". Astronomy & Astrophysics. 529: A160. arXiv:1102.4661. Bibcode:2011A&A...529A.160M. doi:10.1051/0004-6361/201016302. S2CID 118419097.
- Hubrig, S.; et al. (June 2001), "Search for low-mass PMS companions around X-ray selected late B stars", Astronomy and Astrophysics, 372: 152–164, arXiv:astro-ph/0103201, Bibcode:2001A&A...372..152H, doi:10.1051/0004-6361:20010452, S2CID 17507782.
- ^ "* 66 Eri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 13 August 2017.
