Kapteyn’s Star

Star type
g M0-1.5 VI

Distance from Earth
g 12.77 ly

Star Service No.
g NA

Age
g Old halo star

Diameter/Mass/Temp (xSol)
g 173,000 miles (twice that of Jupiter); 0.38; 3,800 K

Brightness (xSol)
g 0.383%

Metallicity
g 7.4 percent of Sol's abundance iron and a mean weight metallicity abundance of elements heavier than hydrogen of almost 10.5 percent of Sol's; due to the scarcity of heavier elements, the star looks a bit more bluish than a main sequence red dwarf of class M

Comparison to Sol
g See chart
g See chart

Picture of star
g NA

Star system features
g Space velocity of 291 km/sec, making it a one of the highest “high” velocity stars known; based on its eccentric, retrograde galactic orbital path, the star may have been born a globular cluster similar to Omega Centauri
g Closest known halo star

Known planets
g NA

Habitable zone
g Accounting for the great infrared output of M-stars like Kapteyn's Star, the equivalent orbital distance for an Earth-type planet may move out to around 0.26 AUs. At a little over half of Mercury's distance in the Solar System, however, the rotation of the planet could become tidally locked with the star so that one side would have perpetual daylight with the other in darkness. Assuming that Kapteyn's Star has at least 39.3 percent of Sol's mass, a small Earth-type rocky planet would complete its orbit the star in around 77 days.

Orbital map
g NA

View from star
g See sky map

Nearby stars
(Star systems with 10 light years)
g LHS 1565, 3.7 ly
g LP 944-20 (brown dwarf), 6.1 ly
g Sirius 2, 7.5 ly
g Epsilon Eridani, 8.5 ly
g 82 Eridani 2, 8.9 ly
g Hip 15689, 9.2 ly
g Gliese 229, 9.3 ly

Map locating star system
g See star map

Location in Earth sky
g In the part of Constellation Pictor, the Painter's Easel, northwest of Beta Pictoris; not visible to the naked eye

Other names
g VZ Pictoris
g GJ 191
g HD 33793
g CD-45°1841, CP(D)-44°612
g SAO 217223
g LHS 29
g LTT 2200
g LFT 395
g CD GCTP 1181
g UGPMF 628
g HIP 24186

Sci-fi mentions
g Frontier: Elite II and Frontier: First Encounters, computer games. Like Groombridge 1618, Kapteyn's Star is uninhabited.
g Doctor Who novels by Kate Orman. Kapteyn's Star is mentioned as home system to several dozen intelligent species who occupy many terrestrial and aquatic ecological niches.

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