Wolf 359 (CN Leonis) is a red dwarf that is located in the constellation Leo, near the ecliptic. At a distance of approximately 7.8 light years from Earth, it has an apparent magnitude of 13.5 and can only be seen with a large telescope. Wolf 359 is one of the nearest stars to the Sun; only the Alpha Centauri system (including Proxima Centauri), Barnard's Star and the brown dwarfs Luhman 16 and WISE 0855−0714 are known to be closer. Its proximity to Earth has led to its mention in several works of fiction.
Wolf 359 is one of the faintest and lowest-mass stars known. At the light-emitting layer called the photosphere, it has a temperature of about 2,800 K, which is low enough for chemical compounds to form and survive. The absorption lines of compounds such as water and titanium(II) oxide have been observed in the spectrum. The surface has a magnetic field that is stronger than the average magnetic field on the Sun. As a result of magnetic activity caused by convection, Wolf 359 is a flare star that can undergo sudden increases in luminosity for several minutes. These flares emit strong bursts of X-ray and gamma ray radiation that have been observed by space telescopes. Wolf 359 is a relatively young star with an age of less than a billion years. No companions or disks of debris have been detected in orbit around it.
Wolf 359 has a stellar classification of M6.5, although various sources list a spectral class of M5.5, M6 or M8. An M-type star is known as a red dwarf: it is called red because the energy emission of the star reaches a peak in the red and infrared parts of the spectrum. Wolf 359 has a very low luminosity, emitting about 0.1% of the Sun's energy. If it were moved to the location of the Sun, it would appear ten times as bright as the full Moon.
At an estimated 9% of the Sun's mass, Wolf 359 is just above the lowest limit at which a star can perform hydrogen fusion through the proton–proton chain reaction: 8% of the Sun's mass. The radius of Wolf 359 is an estimated 16% of the Sun's radius, or about 110,000 km. For comparison, the equatorial radius of the planet Jupiter is 71,492 km, which is 65% as large as Wolf 359's.
Wolf 359 is classified as a UV Ceti?-type flare star, which is a star that undergoes brief, energetic increases in luminosity because of magnetic activity in the photosphere. Its variable star designation is CN Leonis. Wolf 359 has a relatively high flare rate. Observations with the Hubble Space Telescope detected 32 flare events within a two-hour period, with energies of 1027 ergs (1020 joules) and higher. The mean magnetic field at the surface of Wolf 359 has a strength of about 2.2 kG (0.22 teslas), but this varies significantly on time scales as short as six hours. By comparison, the magnetic field of the Sun averages 1 gauss (100 µT), although it can rise as high as 3 kG (0.3 T) in active sunspot regions.During flare activity, Wolf 359 has been observed emitting X-rays and gamma rays.
It follows an orbit through the Milky Way that will bring it as close as 20.5 kly (6.3 kpc) and as distant as 28 kly (8.6 kpc) from the Galactic Center. The galactic orbit has an eccentricity of 0.156, and the star can travel as far as 444 light-years (136 pc) away from the galactic plane. The closest stellar neighbor to Wolf 359 is the red dwarf Ross 128? at 3.79 ly (1.16 pc) away. Approximately 13,850 years ago, Wolf 359 was at its minimal distance of about 7.35 ly (2.25 pc) from the Sun.
Wolf 359 in Space Opera
- "The Best of Both Worlds" (1990), double episode of Star Trek: The Next Generation? written by Michael Piller?. The Battle of Wolf 359, the subject of the second episode, is a pivotal confrontation between the Borg? and a defensive Federation? fleet in 2367, in which a single Borg cube obliterates a substantial fleet of 39 Federation ships. The battle and its aftermath are significant historical events in the fictional history of the Star Trek franchise. The battle appears in greater detail in the Star Trek: Deep Space Nine? pilot episode "Emissary" (1993) and is recounted again by the ex-Borg character Seven of Nine in the Star Trek: Voyager? episode "Infinite Regress" (1998).
- The Space Pioneers (1953), novel in the Tom Corbett, Space Cadet? franchise originated by Carey Rockwell?. Corbett is in training at the Space Academy to become a member of the elite Solar Guard. The action of the novel takes place at the Academy, aboard the training ship Polaris, and on alien worlds, both within the Solar System and in orbit around nearby stars—specifically on Roald?, a planet circling Wolf 359.
- Frontier: Elite II? (1993) and Frontier: First Encounter?s (1995), computer games written by David Braben? et al. Wolf 359 is an industrial and mining colony in these games.
- Terminal Velocity? (1995), video game developed by Terminal Reality and published by 3D Realms. The game has three episodes, the first of which is distributed as shareware. Each episode features three different worlds, making a total of nine levels. The third mission, to destroy the spaceship Moon Dagger, is set in the Wolf 359 planetary system.
- Descent: FreeSpace – The Great War? (1998), computer game developed by Volition, Inc. and published by Interplay Entertainment. As a kind of in-game payback for failing a mission, the unsuccessful player is given a throw-away assignment with little chance of augmenting his score: The player's character is assigned to fly support for an unimportant mission in the "remote" Wolf 359 system (remote from the War theater, not from the Earth!)
- Chindi? (2002), Priscilla Hutchins novel by Jack McDevitt?. Possibly alien satellites of unknown origin have been discovered orbiting various planets of the Solar System, including the Earth. Hutch's crew sets out to find who placed them there and why. In the course of the mission, the lost ship Venture is found in the Wolf 359 system.
- Escape Velocity Nova? (2002), computer game developed and published by Ambrosia Software. The Federation's Bureau of Internal Investigation—the secret police—has its interstellar headquarters on the planet New England in the Wolf 359 system.
- There Will Be Dragons? (2003), first in the series of four Council Wars? novels by John Ringo?. In this series, humanity inhabits two main worlds: the Earth and a planet in the Wolf 359 system. Civilization is in a state of stagnant decline as men dream away their days in luxury under the care of an omnipotent nanny-AI. Revolutionaries act to shatter this crippling system, and they plunge the worlds into a new Dark Age, complete with medieval-style warfare.
- Sword of the Stars? (2006), computer game developed by Kerberos Productions and published by Paradox Interactive. In the game the player chooses one of six races to form an interstellar empire and conquer the galaxy. Key to winning the game's space battles are advanced military technologies, and the game provides the means to "research" them. Character Blasky Yao Hsiang's "research pod" travels in the direction of Wolf 359 on its first subspace journey.
- "Who's Afraid of Wolf 359?" (2008), short story by Ken MacLeod. After running afoul of Security on a space station, the unnamed protagonist is coerced into accepting a dangerous assignment: finding out what happened to an experimental colony orbiting Wolf 359. Find it he does—with rather unexpected results.
- Troy Rising? (2010—2011), trilogy of military science fiction novels by John Ringo?. The Earth is found by aliens arriving through a jumpgate. The first arrivals, the Glatun? are friendly traders, but the next species of aliens to arrive, the Horvath?, demand all of Earth's Platinum-group and other heavy metals production. One human, Tyler Vernon, manages to enlist the aid of the friendly aliens to help Earth's resistance forces free humanity from the oppressive yoke of the Horvath. With the new found support from the Glatun, Tyler and his corporation, Apollo Mining, use the portal to travel to the star system Wolf 359, where they build a space-elevator in orbit around a relatively small gas giant. The lower end of the space elevator is deep in the atmosphere of the gas giant and "mines" helium-3 from its atmosphere. The Helium-3 isotope is used as fuel by both mankind's newly built space fleet and the friendly Glatun. The books go into some of the difficulties of shielding the newly constructed gas mine from the flares and eruptions from Wolf 359.
- Wolf 359? (2014–) a podcast series, in the tradition of the Golden Age of radio dramas like Escape! and Suspense. The U.S.S. Hephaestus Station?, currently on Day 448 of its orbit around red dwarf star Wolf 359, is a tough place for Communications Officer Doug Eiffel. His only company on board the station are stern mission chief Minkowski, insane science officer Hilbert, and Hephaestus Station's sentient, often malfunctioning operating system HERA. He doesn't have much to do for his job other than monitoring static and intercepting the occasional decades-old radio broadcast from Earth, so he spends most of his time creating extensive audio logs about the ordinary, day-to-day happenings within the station.
- Mentioned in the Space: Above and Beyond TV-Series