Image of AC +79 3888 (circled), also known as Gliese 445, located 17.6 light-years from Earth. NASA's Voyager 1 spacecraft, which is on a trajectory out of our solar system, is headed toward an encounter with AC +79 3888. In about 40,000 years, Voyager 1 will be closer to this star than our own sun.
Epoch J2000.0 Equinox J2000.0 (ICRS)
|Right ascension||11h 47m 41.3771s|
|Declination||+78° 41′ 28.178″|
|Apparent magnitude (V)||10.78|
|B−V color index||1.6|
|V−R color index||0.8|
|R−I color index||0.8|
|Radial velocity (Rv)||−119 km/s|
|Proper motion (μ)|| RA: 743.58 mas/yr |
Dec.: 480.47 mas/yr
|Parallax (π)||185.52 ± 1.43 mas|
|Distance||17.6 ± 0.1 ly |
(5.39 ± 0.04 pc)
It is currently 17.6 light-years from Earth and has an apparent magnitude of 10.8. It is visible from north of the Tropic of Cancer all night long, but not to the naked eye. 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. Gliese 445 is also a known X-ray source.
The Voyager 1 probe and Gliese 445 will pass one another within 1.6 light-years in about 40,000 years. By that time Gliese 445 will be in a part of the sky different from its present location. The probe will no longer be operational. Also, given the star's inherent low brightness, even at that distance it would be barely visible to the naked eye of a hypothetical human being, with an apparent magnitude of only 5.72.
While the Voyager probe moves through space towards a 1.6-light-year minimum distance from Gliese 445, the star is rapidly approaching our Sun. At the time the probe passes Gliese 445, the star will be about 1.059 parsecs (3.45 light-years) from our Sun, but with less than half the brightness necessary to be seen with the naked eye. At that time, Gliese 445 will be approximately tied with Ross 248 for being the closest star to our Sun (see List of nearest stars#Future and past).
- "GJ 445". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 29, 2008.
- 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.
- AC+79 3888, entry, Catalogue of nearest stars until 10pc, V. A. Zakhozhaj, CDS ID V/101.
- Page 168, Planets Beyond: Discovering the Outer Solar System, Mark Littmann, Mineola, New York: Courier Dover Publications, 2004, ISBN 0-486-43602-0.
- Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Astrophys. J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
- NASA – Voyager - Mission - Interstellar Mission
- Wikisky image of TYC 4553-192-1 (Gliese 445)