Upsilon4 Eridani
Upsilon4 Eridani is a close binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.56.[2] Based upon parallax measurements, the pair are located around 54.6 parsecs (178 ly) from the Sun.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 17m 53.66241s[1] |
| Declination | −33° 47′ 54.0569″[1] |
| Apparent magnitude (V) | 3.56[2] |
| Characteristics | |
| Spectral type | B8V + B9.5V[3] |
| U−B color index | −0.36[2] |
| B−V color index | −0.12[2] |
| Astrometry | |
| Radial velocity (Rv) | +17.6[4] km/s |
| Proper motion (μ) | RA: +62.52[1] mas/yr Dec.: −7.24[1] mas/yr |
| Parallax (π) | 18.33 ± 0.15[1] mas |
| Distance | 178 ± 1 ly (54.6 ± 0.4 pc) |
| Absolute magnitude (MV) | −0.20[5] |
| Orbit[6] | |
| Period (P) | 5.0103250±0.0000008 d |
| Semi-major axis (a) | 1.902±0.006 mas |
| Eccentricity (e) | 0 |
| Inclination (i) | 146.2±0.1° |
| Periastron epoch (T) | 2454407.7214 ± 0.002 JD |
| Semi-amplitude (K1) (primary) | 62.68±0.17[7] km/s |
| Semi-amplitude (K2) (secondary) | 64.70±0.15[7] km/s |
| Details[6] | |
| υ4 Eri A | |
| Mass | 3.17±0.07 M☉ |
| Radius | 2.32±0.18 R☉ |
| Luminosity | 100.6±4.3 L☉ |
| Surface gravity (log g) | 4.21±0.07 cgs |
| Temperature | 12,930±440[8] K |
| Rotational velocity (v sin i) | 19[8] km/s |
| Age | 146[8] Myr |
| υ4 Eri B | |
| Mass | 3.07±0.07 M☉ |
| Radius | 2.32±0.18 R☉ |
| Luminosity | 87.4±3.3 L☉ |
| Surface gravity (log g) | 4.21±0.07 cgs |
| Temperature | 12,250 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a double-lined spectroscopic binary star system,[10] which means that the Doppler-shifted spectral lines of both components can be distinguished. The pair have a circular orbit with a period of five days. The system is composed of two B-type main-sequence stars: one has a stellar classification of B8V and the other B9.5V.[3] Both stars show HgMn peculiarities in their spectrum,[7] and their properties are nearly identical.[6] The spin rate of the two stars is synchronized to their orbital period.[6] It is possible that a nearby K-type star is also related.[3]
References
- van Leeuwen, F. (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.
- Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
- Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
- 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.
- Hummel, Christian A.; et al. (March 2017), "The orbit of the mercury-manganese binary 41 Eridani", Astronomy & Astrophysics, 600 (L5): 6, arXiv:1703.07668, Bibcode:2016SPIE.9907E..0QH, doi:10.1117/12.2231859.
- Hubrig, S.; et al. (November 2012), "Magnetic fields of HgMn stars", Astronomy & Astrophysics, 547: 24, arXiv:1208.2910, Bibcode:2012A&A...547A..90H, doi:10.1051/0004-6361/201219778, A90.
- David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
- "* ups04 Eri -- Spectroscopic binary". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-13.
- Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x.
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