16 Aurigae

16 Aurigae
Location of 16 Aurigae (circled in red)
Observation data
Epoch J2000      Equinox ICRS
Constellation Auriga
Right ascension 05h 18m 10.576s
Declination +33° 22′ 17.77″
Apparent magnitude (V) 4.552
Characteristics
Evolutionary stage red giant branch
Spectral type K2.5 IIIb CN-0.5
U−B color index +1.26
B−V color index +1.276
Astrometry
Radial velocity (Rv)−28.44 km/s
Proper motion (μ) RA: +28.505±0.713 mas/yr
Dec.: −158.421±0.504 mas/yr
Parallax (π)9.5090±0.5651 mas
Distance340 ± 20 ly
(105 ± 6 pc)
Absolute magnitude (MV)0.28
Orbit
Period (P)434.16±0.03 d
Semi-major axis (a)7.24±1.59 mas
Eccentricity (e)0.1189±0.0026
Inclination (i)52.93±9.46°
Longitude of the node (Ω)56.20±11.65°
Periastron epoch (T)2,448,348.1172±17.1872 JD
Argument of periastron (ω)
(secondary)		70.1±1.2°
Details
16 Aur A
Mass1.30 M☉
Radius19.86±0.89 R☉
Luminosity127±11 L☉
Surface gravity (log g)1.87 cgs
Temperature4,264±58 K
Metallicity [Fe/H]−0.40 dex
Rotational velocity (v sin i)0.0 km/s
Age5.07 Gyr
Other designations
16 Aur, NSV 1909, BD+33°1000, HD 34334, HIP 24727, HR 1726, SAO 57853, PPM 70153, ADS 3872, WDS J05182+3322
Database references
SIMBADdata

16 Aurigae is a triple star system located 340 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.547, and is located about 2/3 of the way from Capella toward Beta Tauri. It also lies in the midst of the Melotte 31 cluster, but is merely a line-of-sight interloper. The system has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.166 arc seconds per annum, and is moving closer to the Earth with a heliocentric radial velocity of −28 km/s.

The primary component is a single-lined spectroscopic binary with an orbital period of 1.19 years and an eccentricity of 0.1189. The visible member is an aging K-type giant star with a stellar classification of K2.5 IIIb CN-0.5; sometimes just given as K3 III. The notation of the former class indicates weak lines of CN in the spectrum. This star is an estimated five billion years old with 1.30 times the mass of the Sun. As a consequence of exhausting the hydrogen at its core, it has expanded to 20 times the Sun's radius. The star is radiating 127 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,264 K.

A third component is a magnitude 10.6 star at an angular separation of 4.2″. It shows a common proper motion with the primary and thus is a likely third member of the system.

References

  1. 1 2 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. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 4 5 6 7 8 9 10 Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". The Astronomical Journal. 150 (3): 88. arXiv:1507.01466. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88. S2CID 118505114.
  4. 1 2 Keenan, P.; McNeil, R. (October 1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245–266. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  5. ↑ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  6. 1 2 3 4 5 Griffin, R. F. (2008). "Spectroscopic binary orbits from photoelectric radial velocities - Paper 198: 48 Piscium, 16 Aurigae, 5 Herculis, and Beta Scuti". The Observatory. 128: 21–56. Bibcode:2008Obs...128...21G.
  7. ↑ Hartkopf, W. I.; et al. (June 30, 2006). "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 2017-08-01. Retrieved 2017-06-02.
  8. 1 2 3 van Belle, Gerard T.; von Braun, Kaspar; Ciardi, David R.; Pilyavsky, Genady; Buckingham, Ryan S.; Boden, Andrew F.; Clark, Catherine A.; Hartman, Zachary; van Belle, Gerald; Bucknew, William; Cole, Gary (2021-12-01). "Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration against Spectral Types and V - K Color". The Astrophysical Journal. 922 (2): 163. arXiv:2107.09205. Bibcode:2021ApJ...922..163V. doi:10.3847/1538-4357/ac1687. ISSN 0004-637X.
  9. 1 2 Matrozis, E.; et al. (November 2013). "Galactic chemical evolution of sulphur. Sulphur abundances from the [S i] λ1082 nm line in giants". Astronomy & Astrophysics. 559: 13. arXiv:1309.0114. Bibcode:2013A&A...559A.115M. doi:10.1051/0004-6361/201322317. S2CID 118421435. A115.
  10. ↑ Massarotti, Alessandro; et al. (2008). "The Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity". The Astronomical Journal. 135 (1): 209–231. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209.
  11. ↑ "16 Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-05-21.
  12. 1 2 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. S2CID 14878976.
  13. ↑ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  14. ↑ Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. S2CID 2603568.