Kruger 60

Kruger 60 A/B

Observation data Epoch J2000      Equinox
Constellation	Cepheus
Kruger 60 A
Right ascension	22h 27m 59.4677s[1]
Declination	+57° 41′ 45.150″[1]
Apparent magnitude (V)	9.59
Kruger 60 B
Right ascension	22h 27m 59.568s[1]
Declination	+57° 41′ 45.28″[1]
Apparent magnitude (V)	11.40
Characteristics
Spectral type	M3V/M4V[2]
U−B color index	1.27/1.3
B−V color index	1.65/1.8
Variable type	None/Flare star
Astrometry
Radial velocity (Rv)	–33.1/–31.9 km/s
Proper motion (μ)	RA: –870.23 mas/yr Dec.: –471.10 mas/yr
Parallax (π)	248.06 ± 1.39 mas
Distance	13.15 ± 0.07 ly (4.03 ± 0.02 pc)
Absolute magnitude (MV)	11.76/13.46
Details
Mass	0.271/0.176[3] M☉
Radius	0.35/0.24[4] R☉
Luminosity	0.010/0.0034 L☉
Temperature	3180/2890 K K
Metallicity	–0.04[5]
Orbit[6]
Primary	Kruger 60 A
Companion	Kruger 60 B
Period (P)	44.67 yr
Semimajor axis (a)	2.383"
Eccentricity (e)	0.410
Inclination (i)	167.2°
Longitude of the node (Ω)	154.5°
Periastron epoch (T)	1970.22
Argument of periastron (ω) (primary)	211.0°
Other designations
DO Cephei, Gl 232-075, GJ 860 A/B, BD +56°2783, HD 239960, LHS 3814/3815, GCTP 5438.00, ADS 15972, Vys 207 A/B, HIP 110893.[7]

Kruger 60 is a binary star system located 13.15 light-years from the Sun. These red dwarf stars orbit each other every 44.6 years.

The larger, primary star is designated component A, while the secondary, smaller star is labeled component B. Component A has about 27% of the Sun's mass and 35% of the Sun's radius. Component B has about 18% of the Sun's mass and 24% of the Sun's radius.^[3][4] Component B is a flare star and has been given the variable star designation "DO Cephei".^[8] It is an irregular flare that typically doubles in brightness and then returns to normal over an 8 minute period.^{[citation needed]}

On average, the two stars are separated by 9.5 AUs, which is roughly the average distance of Saturn from the Sun. However, their eccentric mutual orbit causes their distance to vary between 5.5 AUs at periastron, to 13.5 at apastron.^{[citation needed]}

This system is orbiting through the Milky Way at a distance from the core that varies from 7–9 kpc with an orbital eccentricity of 0.126–0.130.^[9] The closest approach to the Sun will occur in about 88,600 years when this system will come within 1.95 parsecs.^[10]

References

1. ^ ^{a b c d} Perryman, M. A. C. et al; Lindegren; Kovalevsky; Hoeg; Bastian; Bernacca; Crézé; Donati et al. (1997). "The Hipparcos Catalogue". Astronomy and Astrophysics 323: L49–L52. Bibcode 1997A&A...323L..49P. 
2. ^ Henry, Todd J.; et al. (October 1994). "The solar neighborhood, 1: Standard spectral types (K5-M8) for northern dwarfs within eight parsecs". The Astronomical Journal 108 (4): 1437–1444. Bibcode 1994AJ....108.1437H. doi:10.1086/117167. 
3. ^ ^{a b} Delfosse, X.; Forveille; Ségransan; Beuzit; Udry; Perrier; Mayor; et al. (December 2000). "Accurate masses of very low mass stars. IV. Improved mass-luminosity relations". Astronomy and Astrophysics 364: 217–224. arXiv:astro-ph/0010586. Bibcode 2000A&A...364..217D. 
4. ^ ^{a b} Pasinetti Fracassini, L. E.; et al. (February 2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics". Astronomy and Astrophysics 367 (2): 521–524. arXiv:astro-ph/0012289. Bibcode 2001A&A...367..521P. doi:10.1051/0004-6361:20000451.  The data is from the Vizier II/224 catalogue.
5. ^ Bonfils, X.; et al. (November 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.  Only listed for component A.
6. ^ Heintz, W. D. (August 1986). "Orbits of 20 visual binaries". Astronomy and Astrophysics Supplement Series 65 (2): 411–417. Bibcode 1986A&AS...65..411H. 
7. ^ "NSV 14168 – Variable Star". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NSV+14168. Retrieved 2009-09-28. 
8. ^ White, Stephen M.; et al. (December 1989). "A VLA survey of nearby flare stars". Astrophysical Journal Supplement Series 71: 895–904. Bibcode 1989ApJS...71..895W. doi:10.1086/191401. 
9. ^ Allen, C.; Herrera; Herrera, M. A. (1998). "The galactic orbits of nearby UV Ceti stars". Revista Mexicana de Astronomia y Astrofisica 34: 37–46. Bibcode 1998larm.confE.115A. 
10. ^ García-Sánchez, J.; et al. (November 2001). "Stellar encounters with the solar system". Astronomy and Astrophysics 379 (2): 634–659. Bibcode 2001A&A...379..634G. doi:10.1051/0004-6361:20011330. 

Further reading

• James Kaler, Extreme Stars, (Cambridge: Cambridge UP, 2001), p. 32.
• Hires LRGB CCD Image