The Star of Kapteyn, the Halo Star Nearest to the Solar System

Kapteyn's Star is situated a mere 12.8 light-years away from Earth, making it the 24th closest star to the Sun, yet its origins hail from a far more distant past. This celestial body is distinguished by a dynamic significantly different from that of other stars in the solar vicinity. Its orbit is, in fact, retrograde, and it traverses space at exceptionally high speeds; imagine that merely 10,000 years ago, Kapteyn's Star was situated only 7 light-years from Earth!

Reconstructing its evolutionary history, commencing with its motion in space and examining the abundance of elements in its atmosphere, it has been discovered that Kapteyn's Star most likely once belonged to the Omega Centauri globular cluster, the remnants of a dwarf galaxy torn apart by the tidal forces of the Milky Way, which today is 16,000 light-years distant from Earth.

You may now be intrigued to learn how to observe this peculiar star so close to Earth with the naked eye. Regrettably, despite its relative proximity, Kapteyn's Star exhibits a magnitude of +10.9, rendering it imperceptible to the unaided eye. This is attributable to its physical properties: the star is, in fact, a red subdwarf with a surface temperature of merely 3500 K, while its mass and diameter are less than 30% of those of the Sun. This implies a luminosity that is a mere 0.012 of the Sun's, thus making Kapteyn's Star too faint to be discerned by the naked eye from Earth.

Credit: Palomar Observatory.

Written by Chatsonic