Theta Persei


Theta Persei (Theta Per, θ Persei, θ Per) is a star system 37 light years away from Earth, in the constellation Perseus. It is one of the closest naked-eye stars.

θ Persei
Perseus constellation map.svg
Red circle.svg
Location of θ Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 02h 44m 11.98704s[1]
Declination +49° 13′ 42.4111″[1]
Apparent magnitude (V) 4.11[2] / 9.987[3]
θ Per A
Evolutionary stage Main sequence
Spectral type F8 V[4]
U−B color index +0.00[5]
B−V color index +0.49[5]
θ Per B
Spectral type M1.5 V[6]
B−V color index +1.48[7]
Radial velocity (Rv)+24.32[8] km/s
Proper motion (μ) RA: +334.66[1] mas/yr
Dec.: -89.99[1] mas/yr
Parallax (π)89.87 ± 0.22 mas[1]
Distance36.29 ± 0.09 ly
(11.13 ± 0.03 pc)
Absolute magnitude (MV)3.88[9]
Period (P)2,720 yr
Semi-major axis (a)22.289″
Eccentricity (e)0.13
Inclination (i)75.44°
Longitude of the node (Ω)128°
Periastron epoch (T)B 1613
Argument of periastron (ω)
θ Per A
Mass1.138±0.010[11] M
Radius1.319±0.011[11] R
Luminosity2.235±0.040[11] L
Surface gravity (log g)4.43±0.17[12] cgs
Temperature6,328±86[12] K
Metallicity [Fe/H]−0.03±0.09[12] dex
Age4.0±0.4[11] Gyr
θ Per B
Mass0.521±0.052[3] M
Radius0.498±0.017[3] R
Temperature3,685±60[3] K
Metallicity [Fe/H]−0.03±0.09[12] dex
Age2.4[3] Gyr
Other designations
θ Per, BD+48°746, GJ 107, CCDM J02441+4913, IDS 02374+4848, WDS J02442+4914
θ Per A: 13 Persei, HR 799, HD 16895, HIP 12777, FK5 93, GC 3277, PPM 45428, SAO 38288
θ Per B: 2MASS J02441025+4913540
Database references
θ Per A
θ Per B

The primary star is a yellowish dwarf (main sequence) star of spectral type F8V, which is somewhat larger and brighter than the Sun, but still within the range considered to have the potential for Earth-like planets. There is also a red dwarf companion of spectral type M1.V, orbiting about 250 AU from the primary. It has a Gaia Data Release 2 parallax of 89.2871±0.1534 mas, corresponding to a distance of 11.2 pc.[13]

An 11th-magnitude star is listed in double-star catalogues as component C of the multiple system. It was 95 away from component A in 2002,[14] although the separation is rapidly increasing as it is a distant background object with a very different proper motion to the other two stars.[15] An unconfirmed companion, possibly a brown dwarf, was reported 6.2 from θ Persei B in 2010.[16]


  1. ^ a b c d e 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, S2CID 18759600.
  2. ^ Van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085.
  3. ^ a b c d e Mann, Andrew W.; Feiden, Gregory A.; Gaidos, Eric; Boyajian, Tabetha; von Braun, Kaspar (2015). "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius". The Astrophysical Journal. 804 (1): 38. arXiv:1501.01635. Bibcode:2015ApJ...804...64M. doi:10.1088/0004-637X/804/1/64. S2CID 19269312.
  4. ^ Abt, H. A. (1981). "Visual multiples. VII. MK classifications". The Astrophysical Journal Supplement Series. 45: 437. Bibcode:1981ApJS...45..437A. doi:10.1086/190719.
  5. ^ a b Hoffleit, D.; Jaschek, C. (1991). The Bright Star Catalogue. New Haven: Yale University Observatory.
  6. ^ Alonso-Floriano, F. J.; Morales, J. C.; Caballero, J. A.; Montes, D.; Klutsch, A.; Mundt, R.; Cortés-Contreras, M.; Ribas, I.; Reiners, Ansgar; Amado, P. J.; Quirrenbach, A.; Jeffers, S. V. (2015). "CARMENES input catalogue of M dwarfs" (PDF). Astronomy & Astrophysics. 577: A128. arXiv:1502.07580. doi:10.1051/0004-6361/201525803. S2CID 53135130.
  7. ^ Weis, Edward W. (1999). "Photometry of Late Dwarf Stars". The Astronomical Journal. 117 (6): 3021–3024. Bibcode:1999AJ....117.3021W. doi:10.1086/300900.
  8. ^ Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477, Bibcode:2002ApJS..141..503N, doi:10.1086/340570, S2CID 51814894.
  9. ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  10. ^ Boulé, Cory; Andrews, Kaitlyn; Penfield, Andrew; Puckette, Ian; Goodale, Keith A.; Harfenist, Steven A. (2017). "Determining Binary Star Orbits Using Kepler's Equation" (PDF). Journal of Double Star Observations. 13 (2): 189. Bibcode:2017JDSO...13..189B.
  11. ^ a b c d Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101, S2CID 18993744. See Table 10, 12.
  12. ^ a b c d Bonfils, Xavier; Delfosse, Xavier; Udry, Stéphane; Santos, Nuno C.; Forveille, Thierry; Ségransan, Damien (2005). "Metallicity of M dwarfs. I. A photometric calibration and the impact on the mass-luminosity relation at the bottom of the main sequence". Astronomy and Astrophysics. 442 (2): 635–642. arXiv:astro-ph/0503260. Bibcode:2005A&A...442..635B. doi:10.1051/0004-6361:20053046. S2CID 13900901.
  13. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  14. ^ Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
  15. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  16. ^ Tanner, Angelle M.; Gelino, Christopher R.; Law, Nicholas M. (2010). "A High-Contrast Imaging Survey ofSIM Lite Planet Search Targets". Publications of the Astronomical Society of the Pacific. 122 (896): 1195–1206. arXiv:1007.4315. Bibcode:2010PASP..122.1195T. doi:10.1086/656481. S2CID 118459054.

External linksEdit

  • "Simbad Query Result". Simbad. Retrieved March 28, 2007.
  • "Draft of SIM target stars". JPL. Archived from the original on February 2, 2007. Retrieved March 28, 2007.