Gliese 445

Gliese 445
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Camelopardalis
Right ascension 11h 47m 41.3771s[1]
Declination +78° 41′ 28.178″[1]
Apparent magnitude (V) 10.78[1]
Characteristics
Spectral type M3.5[1]
B−V color index 1.6[1]
V−R color index 0.8[1]
R−I color index 0.8[1]
Astrometry
Radial velocity (Rv)−119[1] km/s
Proper motion (μ) RA: 743.58[1] mas/yr
Dec.: 480.47[1] mas/yr
Parallax (π)185.52 ± 1.43[1] mas
Distance17.6 ± 0.1 ly
(5.39 ± 0.04 pc)
Details
Mass0.15[2]–0.30[3] M☉
Radius0.320[3] R☉
Other designations
Gliese 445, Gl 445, G 254-29, AC+79 3888, HIP 57544, LFT 849, LHS 2459, LTT 13235, NLTT 28539,[1] PLX 2722, Proxima Camelopardalis[4]
Database references
SIMBADdata
ARICNSdata

Gliese 445 (Gl 445) is an M-type main sequence star in the constellation of Camelopardalis, close to Polaris. It is currently 17.6 light-years from the Sun and has an apparent magnitude of 10.8.[1] It is visible from north of the Tropic of Cancer all night long, but not to the naked eye.[5] Because the star is a red dwarf with a mass only a quarter to a third of that of our Sun, scientists question the ability of this system to support life.[5] Gliese 445 is also a known X-ray source.[6]

Distance

Gliese 445 distance estimates

Source Parallax, mas Distance, pc Distance, ly Distance, Pm Ref.
Woolley et al. (1970) 195±6 5.13+0.16
−0.15		 16.7±0.5 158.2+5
−4.7		 [7]
Gliese & Jahreiß (1991) 191.5±5.3 5.22+0.15
−0.14		 17±0.5 161.1+4.6
−4.3		 [8]
van Altena et al. (1995) 192.2±6.0 5.2+0.17
−0.16		 17±0.5 160.5+5.2
−4.9		 [9]
Perryman et al. (1997) (Hipparcos) 185.48±1.43 5.39±0.04 17.58+0.14
−0.13		 166.4±1.3 [10]
Perryman et al. (1997) (Tycho) 195.40±39.10 5.1+1.3
−0.9		 16.7+4.2
−2.8		 157.9+39.5
−26.3		 [11]
van Leeuwen (2007) 186.86±1.70 5.35±0.05 17.45±0.16 165.1±1.5 [12]
RECONS TOP100 (2012) 187.26±1.64[nb 1] 5.34±0.05 17.42±0.15 164.8+1.5
−1.4		 [13]

Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.

Voyager 1

The star is notable because the Voyager 1 probe will pass within 1.6 light years of it in about 40,000 years,[14] when Gliese 445 makes a close pass by our solar system (see below).

Solar encounter

Distances of the nearest stars from 20,000 years ago until 80,000 years in the future

While the Voyager probe flies through space slowly closing on Gliese 445, the star is rapidly approaching the Sun. At the time the probe passes Gliese 445, the star will be about 1.059 parsecs (3.45 light-years) from the Sun,[2] but with less than half the brightness necessary to be seen with the naked eye.[5] But the dwarf star will still be farther away than other stars have achieved.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 LHS 2459 -- High proper-motion Star, database entry, SIMBAD. Accessed on line July 29, 2008.
  2. ↑ 2.0 2.1 Bobylev, Vadim V. (March 2010). "Searching for Stars Closely Encountering with the Solar System". Astronomy Letters 36 (3): 220–226. arXiv:1003.2160. Bibcode:2010AstL...36..220B. doi:10.1134/S1063773710030060.
  3. ↑ 3.0 3.1 AC+79 3888, entry, Catalogue of nearest stars until 10pc, V. A. Zakhozhaj, CDS ID V/101.
  4. ↑ The Closest Stars
  5. ↑ 5.0 5.1 5.2 Page 168, Planets Beyond: Discovering the Outer Solar System, Mark Littmann, Mineola, New York: Courier Dover Publications, 2004, ISBN 0-486-43602-0.
  6. ↑ Schmitt JHMM, Fleming TA, Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Ap J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
  7. ↑ Woolley R.; Epps E. A.; Penston M. J.; Pocock S. B. (1970). "Woolley 445". Catalogue of stars within 25 parsecs of the Sun. Retrieved 2014-11-23.
  8. ↑ Gliese, W. and Jahreiß, H. (1991). "Gl 445". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2014-11-23.
  9. ↑ Van Altena W. F., Lee J. T., Hoffleit E. D. (1995). "GCTP 2722". The General Catalogue of Trigonometric Stellar Parallaxes (Fourth ed.). Retrieved 2014-11-23.
  10. ↑ Perryman et al. (1997). "HIP 57544". The Hipparcos and Tycho Catalogues. Retrieved 2014-11-23.
  11. ↑ Perryman et al. (1997). "HIP 57544". The Hipparcos and Tycho Catalogues. Retrieved 2014-11-23.
  12. ↑ van Leeuwen F. (2007). "HIP 57544". Validation of the new Hipparcos reduction. Retrieved 2014-11-23.
  13. ↑ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012. Retrieved 2014-11-23.
  14. ↑ NASA – Voyager - Mission - Interstellar Mission

Notes

  1. ↑ Weighted parallax based on parallaxes from van Altena et al. (1995) and van Leeuwen (2007).

External links