Wolf 359

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This article is about the star Wolf 359. For the article about the fictional Star Trek battle, see Battle of Wolf 359.
Wolf 359

Wolf 359 is shown near the ecliptic in the southern region of Leo. It is invisible to the naked eye.
Observation data
Epoch J2000
Constellation
(pronunciation)		 Leo
Right ascension 10h 56m 28.99s[1]
Declination +07° 00′ 52.0″[1]
Apparent magnitude (V) 13.54[1]
Characteristics
Spectral type M6.5 Ve[1]
U-B color index +1.54[1]
B-V color index +2.01[1]
Variable type Flare star
Astrometry
Radial velocity (Rv) +19±1[2] km/s
Proper motion (μ) RA: -3842[1] mas/yr
Dec.: -2725[1] mas/yr
Parallax (π) 419.10 ± 2.10 mas
Distance 7.78 ± 0.04 ly
(2.39 ± 0.01 pc)
Absolute magnitude (MV) 16.64
Details
Mass 0.09[3] M☉
Radius 0.16[4] R☉
Luminosity 0.0009[5] L☉
Temperature 2,800 ± 100[6] K
Rotation <3.0 km/s[2]
Age 1–3.5 × 108[6] years
Other designations
CN Leonis, CN Leo, GJ 406, G 045-020, LTT 12923, LFT 750, LHS 36,[1] GCTP 2553.

Wolf 359 is a star located approximately 2.4 parsecs or 7.7 light years from Earth. It is one of the nearest stars; only the Alpha Centauri system and Barnard's star are known to be closer. Its celestial position is in the constellation Leo, near the ecliptic. It is an extremely faint red dwarf and too dim to be visible to the naked eye, with a visual magnitude of 13.54. It is a flare star that undergoes random increases in luminosity because of magnetic activity on its surface.

Contents

[edit] Properties

The star was discovered using astrophotography by German astronomer Max Wolf in 1918. Its closest neighbor is Ross 128, 1.16 pc or 3.79 ly away.[7] In 2001 this became the first star other than the Sun to have the spectrum of its corona observed from a ground-based telescope.[8]

The projected rotational velocity of this star's equator is less than 3 km/s; below the threshold of detection through spectral line broadening.[2]

It is classified as a UV Ceti-type flare star,[9] and has a relatively high flare rate. Observations with the Hubble Space Telescope (HST) detected 32 flare events within a two hour period, with energies of 1027 ergs (1020 joules) and higher.[10] The mean magnetic field has a strength of about 2.2 kG, but this varies significantly on time scales a short as six hours.[11] By comparison, the magnetic field of the Sun averages 1 Gauss, although it can rise as high as 3 kG in active sunspot regions.[12]

A search of this star by the HST revealed no stellar companions. However this does not preclude the presence of smaller companions that are below the telescope's detection limit, such as a planet in a close orbit.[13] No excess infrared emission has been detected, which may indicate the lack of a debris disk in orbit around this star.[14]

[edit] See also

[edit] References

  1. ^ a b c d e f g h i SIMBAD Query: V* CN Leo -- Flare Star. Centre de Données astronomiques de Strasbourg. Retrieved on 2007-07-16.
  2. ^ a b c Mohanty, Subhanjoy; Basri, Gibor (2003). "Rotation and Activity in Mid-M to L Field Dwarfs". The Astrophysical Journal 583 (1): 451-472. 
  3. ^ Staff (June 8, 2007). List of the Nearest 100 Stellar Systems. Research Consortium on Nearby Stars. Retrieved on 2007-07-16.
  4. ^ Doyle, J. G.; Butler, C. J. (1990). "Optical and infrared photometry of dwarf M and K stars". Astronomy and Astrophysics 235 (1-2): 335-339. 
  5. ^ West, Frederick R. (2002). "Letter to the Editor: The Corona of CN Leonis (Gliese 406) and its Possible Detection at Radio Frequencies". The Journal of the American Association of Variable Star Observers 30 (2): 149-150. 
  6. ^ a b Pavlenko, Ya. V.; Jones, H. R. A.; Lyubchik, Yu.; Tennyson, J.; Pinfield, D. J. (2006). "Spectral energy distribution for GJ406". Astronomy and Astrophysics 447 (2): 709-717. doi:10.1051/0004-6361:20052979. 
  7. ^ Wolf 359. SolStation Company. Retrieved on 2006-08-10.
  8. ^ Schmitt, J. H. M. M. ; Wichmann, R. (2001). "Ground-based observation of emission lines from the corona of a red-dwarf star". Nature 412 (2): 508-510. doi:10.1038/35087513. 
  9. ^ Gershberg, R. E.; Shakhovskaia, N. I. (1983). "Characteristics of activity energetics of he UV Cet-type flare stars". Astrophysics and Space Science 95 (2): 235-253. doi:10.1007/BF00653631. 
  10. ^ Robinson, R. D.; Carpenter, K. G.; Percival, J. W.; Bookbinder, J. A. (1995). "A Search for Microflaring Activity on dMe Flare Stars. I. Observations of the dM8e Star CN Leonis". Astrophysical Journal 451: 795-805. doi:10.1086/176266. 
  11. ^ Reiners, A.; Schmitt, J. H. M. M.; Liefke, C. (2007). "Rapid magnetic flux variability on the flare star CN Leonis". Astronomy and Astrophysics 466 (2): L13-L16. 
  12. ^ Staff. "Calling Dr. Frankenstein! : Interactive Binaries Show Signs of Induced Hyperactivity", National Optical Astronomy Observatory, January 7, 2007. Retrieved on 2006-05-24. 
  13. ^ Daniel J. Schroeder et al (2000). "A Search for Faint Companions to Nearby Stars Using the Wide Field Planetary Camera 2". The Astronomical Journal 119 (2): 906-922. 
  14. ^ Gautier, T. N.; Beichman, C. A.; Bryden, G.; Chen, C. H.; Gordon, K. D.; Rieke, G. H.; Stansberry, J. A.; Stapelfeldt, K. R.; Trilling, D. E.; Werner, M. W.; MIPS (2004). "Far Infrared Properties of M Dwarfs" (PDF). Bulletin of the American Astronomical Society 36: 1431-. 

[edit] External links