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Selected Star Systems Within 65 Light Years (20 Parsecs)
Asterisks indicate exoplanetary systems. For more information, see Table of Selected Nearby Star Systems.
This diagram provides a visual summary of the Solar neighborhood, seen from the perspective of an observer located in the constellation Ursa Minor. Within 65 light years of the Sun, it includes:
The volume of space within 65 light years (20 parsecs) of our Sun is well studied and better understood than any other region of the extrasolar universe. If our species ever expands into interstellar space, the Solar neighborhood will be the scene of our earliest missions of exploration and colonization. Key attributes of this region are probably typical of our entire Local Bubble.
Our immediate neighborhood lacks the very brightest species of stars, represented by spectral classes O and B. Thus the most luminous star systems within this 20-parsec radius contain either giants (e.g., Capella, Arcturus, Pollux), subgiants (e.g., Procyon), or blue-white main sequence stars of spectral class A (e.g., Sirius, Vega). A total of 15 systems within this radius contain A stars (see SolSation.com); shown here are 11, some of which contain binary or multiple stars.
In order of decreasing mass and luminosity, the remaining spectral classes represented in our neighborhood are F, G, K, and M. Stellar populations increase as mass decreases, so that each spectral class has a much larger population than the one above it. In addition to the 15 systems containing A stars, the local neighborhood includes almost 90 yellow-white stars of type F (like Upsilon Andromedae), more than 130 yellow stars of type G (like the Sun and Tau Ceti), more than 300 orange stars of type K (like Epsilon Eridani) and several hundred red dwarfs of type M (like GJ 876).
Because the present diagram focuses on exoplanetary systems and bright “landmark” stars (those most visible from the greatest distances), it is misleading. We should picture this region with a heavy peppering of dim red stars, along with hundreds more of the yellowish and orange stars that furnish the best candidates for planetary hosts. Such detail, unfortunately, would make a small-format diagram indecipherable.
Absent from our neighborhood are the extreme objects that typically fascinate astronomers – pulsars, quasars, black holes, neutron stars, dark matter filaments. The closest known neutron star is about 200 light years away, while the closest known black hole is 1600 light years away. If we seek prodigies nearby, we should consider giant stars like Arcturus, white dwarfs like the companion of Sirius, and multiple star systems like the Castor sextet.
All text is copyright Raymond Harris 2006-2011. Image credits appear in the accompanying caption.