SZ Crateris

SZ Crateris A/B
Observation data
Epoch J2000      Equinox J2000
Constellation Crater
Right ascension 11h 21m 26.6645s[1]
Declination −20° 27′ 13.619″[1]
Apparent magnitude (V) 8.61/11.0[2]
Characteristics
Spectral type K5V/M1V[2]
U−B color index +1.20[3]/—
B−V color index +1.36[3]/—
Variable type BY Dra
Astrometry
Radial velocity (Rv) +3.7[4] km/s
Proper motion (μ) RA: +178.48[1] mas/yr
Dec.: −115.16[1] mas/yr
Parallax (π) 76.00 ± 1.70[1] mas
Distance 42.9 ± 1 ly
(13.2 ± 0.3 pc)
Absolute magnitude (MV) 8.01/10.4[5]
Details
Radius 0.66/0.42[6] R☉
Surface gravity (log g) 4.5[7]/—
Temperature 5,450[7]/— K
Metallicity \begin{smallmatrix}\left[\frac{Fe}{H}\right]\ =\ 0.04\end{smallmatrix}[7]
Rotational velocity (v sin i) 4.5[7]/— km/s
Age (1.94 ± 0.20) × 108[8] years
Other designations
SZ Crt, BD-19 3242, GJ 425, HD 98712, LTT 4204, SAO 179801, HIP 55454.[9]
B: LTT 4205.[10]

SZ Crateris is a binary star system. Both components belong to the main sequence: the primary star has a spectral classification of K5V while the secondary is a red dwarf of spectral class M0V. The radius of the primary is about 66% the radius of the Sun, while the secondary member is only about 42% of the solar radius.[6] In 1994, the two stars were separated by 5.1 arc seconds, which is equivalent to 112.41 astronomical units.[11]

SZ Crateris is classified as a marginal BY Draconis variable, and has an optical variability cycle of 11.58 days. (The star causing the variability is unspecified.)[12] Compared to the Sun, SZ Crateris has a slightly higher proportion of elements other than hydrogen and helium.[7] Based upon gyrochronology, the estimated age of this star is under 200 million years.[8]

The SZ Crateris system is a member of the Ursa Major moving group of stars that have similar motions through space.[7] The space velocity components of this system are U = +13.86 ± 0.37, V = –3.51 ± 1.97 and W = +1.65 ± 1.53 km/s.[13] It is on an orbit through the Milky Way that has an orbital eccentricity of 0.092, which will bring it as close as 26.06 kly (7.99 kpc) to the galactic core, and as distant as 31.31 kly (9.60 kpc). The inclination of the orbit carries the system as much as 0.352 kly (0.108 kpc) from plane of the galactic disk.[14]

References

  1. ^ a b c d e Perryman, M. A. C.; et al (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics 323: L49–L52. Bibcode 1997A&A...323L..49P. 
  2. ^ a b Reid, I. Neill; et al. (July 2004). "Meeting the Cool Neighbors. VIII. A Preliminary 20 Parsec Census from the NLTT Catalogue". The Astronomical Journal 128 (1): 463–483. arXiv:astro-ph/0404061. Bibcode 2004AJ....128..463R. doi:10.1086/421374. 
  3. ^ a b Corben, P. M.; et al. (1972). "U, B, V photometry of 500 southern stars". Monthly Notes of the Astronomical Society of South Africa 31: 7–22. Bibcode 1972MNSSA..31....8C. 
  4. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". Proceedings from IAU Symposium no. 30. London, England: Academic Press. p. 57. http://adsabs.harvard.edu/abs/1967IAUS...30...57E. Retrieved 2007-11-09. 
  5. ^ The absolute magnitude Mv is determined as follows:
    Mv = m - 5((log10 DL) - 1) = 8.61 - 5((log10 13.2) - 1) = 8.01
    where m is the apparent magnitude and DL is the distance from the Sun in parsecs.
  6. ^ a b Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (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. 
  7. ^ a b c d e f Paulson, Diane B.; Yelda, Sylvana (May 2006). "Differential Radial Velocities and Stellar Parameters of Nearby Young Stars". The Publications of the Astronomical Society of the Pacific 118 (843): 706–715. arXiv:astro-ph/0605433. Bibcode 2006PASP..118..706P. doi:10.1086/504115. 
  8. ^ a b Barnes, Sydney A. (November 2007). "Ages for Illustrative Field Stars Using Gyrochronology: Viability, Limitations, and Errors". The Astrophysical Journal 669 (2): 1167–1189. Bibcode 2007ApJ...669.1167B. doi:10.1086/519295. 
  9. ^ "V* SZ Crt -- Variable of BY Dra type". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=SZ+Crt. Retrieved 2010-02-18. 
  10. ^ "LTT 4205 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=CCDM%20J11214-2027%20B. Retrieved 2010-02-18. 
  11. ^ Poveda, A.; Herrera, M. A.; Allen, C.; Cordero, G.; Lavalley, C. (April 1994). "Statistical studies of visual double and multiple stars. II. A catalogue of nearby wide binary and multiple systems.". Revista Mexicana de Astronomia y Astrofisica 28 (1): 43–89. Bibcode 1994RMxAA..28...43P. 
  12. ^ Cutispoto, G. (October 1996). "Long-term monitoring of active stars. V. UBV(RI)_ c_ photometry collected in Feb.-Mar. 1990.". Astronomy and Astrophysics Supplement 119 (2): 281–292. Bibcode 1996A&AS..119..281C. doi:10.1051/aas:1996245. 
  13. ^ Karataş, Y.; Bilir, S.; Eker, Z.; Demircan, O. (April 2004). "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution". Monthly Notices of the Royal Astronomical Society 349 (3): 1069–1092. arXiv:astro-ph/0404219. Bibcode 2004MNRAS.349.1069K. doi:10.1111/j.1365-2966.2004.07588.x. 
  14. ^ Allen, C.; Herrera, M. A. (April 1998). "The Galactic Orbits of Nearby UV Ceti Stars". Revista Mexicana de Astronomia y Astrofisica 34: 37–46. Bibcode 1998RMxAA..34...37A.