c Ursae Majoris
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 09h 14m 20.542s[1] |
| Declination | +61° 25′ 23.94″[1] |
| Apparent magnitude (V) | 5.18[2] |
| Characteristics | |
| Spectral type | G0 V[3] |
| U−B color index | +0.08[4] |
| B−V color index | +0.605±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −14.3[5] km/s |
| Proper motion (μ) | RA: −7.826 mas/yr [1] Dec.: −31.083 mas/yr [1] |
| Parallax (π) | 49.4145±0.1544 mas [1] |
| Distance | 66.0 ± 0.2 ly (20.24 ± 0.06 pc) |
| Absolute magnitude (MV) | 3.75±0.06/8.2±0.6[3] |
| Orbit [3] | |
| Period (P) | 16.239631 ± 0.000015 d |
| Semi-major axis (a) | 2.9±0.2 mas |
| Eccentricity (e) | 0.10635±0.00054 |
| Inclination (i) | 106.0±12.0° |
| Longitude of the node (Ω) | 107.0±14.0° |
| Periastron epoch (T) | 2454358.214 ± 0.013 HJD |
| Argument of periastron (ω) (secondary) | 137.18±0.29° |
| Semi-amplitude (K1) (primary) | 35.344±0.018 km/s |
| Semi-amplitude (K2) (secondary) | 64.97±0.27 km/s |
| Details | |
| c UMa A | |
| Mass | 1.213[6] M☉ |
| Radius | 2.6±0.1[3] R☉ |
| Surface gravity (log g) | 3.98[7] cgs |
| Temperature | 5,871[7] K |
| Metallicity [Fe/H] | −0.13[7] dex |
| Rotational velocity (v sin i) | 5.59[8] km/s |
| Age | 5.41[6] Gyr |
| c UMa B | |
| Mass | 0.59−0.66[3] M☉ |
| Radius | 0.50±0.14[3] R☉ |
| Luminosity | 0.08±0.04[3] L☉ |
| Other designations | |
| c UMa, 16 UMa, BD+62° 1058, HD 79028, HIP 45333, HR 3648, SAO 14819[9] | |
| Database references | |
| SIMBAD | data |
c Ursae Majoris is the Bayer designation for a double-lined spectroscopic binary star system in the northern constellation of Ursa Major. It has an apparent visual magnitude of 5.18,[2] which indicates that is visible to the naked eye. Parallax measurements yield an estimated distance of 66 light years from the Sun.[1] The star is moving closer to the Earth with a heliocentric radial velocity of −14 km/s.[5]
The spectroscopic binary nature of this system was among the first 75 such discovered by the Dominion Astrophysical Observatory in 1919.[10] The pair orbit each other every 16.2 days with an eccentricity of 0.1. The semimajor axis of their orbit has an angle of around 2.9 mas , and the plane of the orbit is inclined to the line of sight at an angle of around 106°.[3]
The primary component has a stellar classification of G0 V, suggesting that it is a G-type main sequence star similar to ι Per. It has a mass of about 1.2 times the mass of the Sun, and 2.6 times the Sun's radius. The magnitude difference between the two components is estimated to be 4.5±0.6. The estimated properties of the secondary indicate that it is most likely a K-type main sequence star. The system displays no indication of chromospheric activity.[3]
The system has been examined for evidence of an infrared excess that could indicate the presence of a circumstellar debris disk, but none has been found.[11] At present, c UMa is moving in Earth's direction with a radial velocity of −14.3 km/s. Perihelion passage will occur in 1.3 million years when the system comes within 10 ly (4 pc) of the Sun.[5] This is most likely a member of the Milky Way's thin disk population of stars.[6]
References
[edit ]- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv:2012.01533 . Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657 . S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b c d e f g h i Francis C., Fekel; et al. (February 2015), "New Precision Orbits of Bright Double-Lined Spectroscopic Binaries. IX. HD 54371, HR 2692, and 16 Ursa Majoris", The Astronomical Journal, 149 (2): 13, Bibcode:2015AJ....149...63F, doi:10.1088/0004-6256/149/2/63, hdl:2152/34404 , S2CID 1343979, 63.
- ^ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", SIMBAD Astronomical Database, Bibcode:1986EgUBV........0M.
- ^ a b c Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648 , Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, S2CID 59039482, A35.
- ^ a b c Ramírez, I.; et al. (February 2013), "Oxygen abundances in nearby FGK stars and the galactic chemical evolution of the local disk and halo", The Astrophysical Journal, 764 (1): 78, arXiv:1301.1582 , Bibcode:2013ApJ...764...78R, doi:10.1088/0004-637X/764/1/78, S2CID 118751608.
- ^ a b c 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, arXiv:astro-ph/0603770 , Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
- ^ Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter" (PDF), Astronomy and Astrophysics, 520: A79, arXiv:1002.4391 , Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725, S2CID 43455849, archived from the original (PDF) on 2017年09月22日, retrieved 2018年11月04日.
- ^ "c UMa". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2016年07月18日.
{{cite web}}: CS1 maint: postscript (link) - ^ Plaskett, J. S.; et al. (1919), "Fourth list of spectroscopic binaries", Journal of the Royal Astronomical Society of Canada, 13: 372–378, Bibcode:1919JRASC..13..372P.
- ^ Eiroa, C.; et al. (July 2013), "DUst around NEarby Stars. The survey observational results", Astronomy & Astrophysics, 555: A11, arXiv:1305.0155 , Bibcode:2013A&A...555A..11E, doi:10.1051/0004-6361/201321050, S2CID 377244.