Wolf 359 - the third nearest star system

 Wolf 359, also known as the variable star CN Leonis, is an obscure magnitude-13.4 red-dwarf star near the ecliptic in the constellation Leo.  It is the 359th entry in a catalog of high-proper-motion stars compiled by astronomer Max Wolf over a century ago.  At this time of year (October), it is an early-morning object in the eastern sky just before dawn.

E-P5 + Rokinon 135mm f/2, ISO 1600, 60 s. 2-deg square.

Wolf 359 has a proper motion of 4.7" per year and is 7.8 ly distant.  The only nearer stars are Barnard's Star (6 ly) and the three-star Alpha Centauri system (4.3 ly).  It is a typical red-dwarf flare star with a mass of about 11% of our sun and a hydrogen-burning lifetime of about 5 trillion years.  

Since about ten years ago, it is necessary to make a distinction between the nearest stars and the nearest extra-solar objects.  In 2013 Penn-State astronomer Kevin Luhman announced the discovery of a binary brown-dwarf system at a distance of 6.5 ly, closer than Wolf 359.  This system is now known as Luhman 16.  Its two components each have a mass of about 3% of our sun (or ≈ 30 Jupiters) .  A brown dwarf is a "failed star".  It does not have enough mass to raise its core temperature high enough to initiate hydrogen fusion.  Brown dwarfs glow with the heat of their formation and gradually cool over time.  Luhman also announced the discovery of a third object (Wise 0855-0714), a sub-brown dwarf at a distance of 7.4 ly.  This object has a mass of between 3-10 Jupiters and an effective temperature less than the freezing point of water.

The images above and below were taken around 5 am MDT on Oct 25, when the planet Venus was only 2.4° away. Venus was shining at magnitude -4.4, 13.7 million times brighter than Wolf 359.

Venus, Wolf 359 (circled), satellite trail.