Although the definition will vary from person to person, I will assume close means within “20 light years,” a region which encompasses the 106 closest stars to the Sun.
Also, I will assume that “stars like the Sun” refers to dwarf class G-stars since the Sun is a G2V* star.
Within these parameters, we find three stars, the first of which, conveniently, is within the closest star system to the Sun.
1st: Alpha Centauri A
Distance: 4.344 light years from the Sun.
Within the Alpha Centauri system, the closest one to the Sun, we find Alpha Centauri A, a G2V star. Also known as Rigel Kentarus, Alpha Centauri A is 4.344 light years from us. In isolation, Alpha Centauri A would shine at magnitude 0.1, about 3.8 times dimmer than Sirius. It is 1.08 times more massive and 1.8 times larger in terms of volume than the Sun and is 1.5 times as luminous. With an effective temperature of approximately 5,800 K, it is only slightly hotter than the Sun (effective temperature 5,777 K).
Alpha Centauri A is part of the Alpha Centauri system, which marks the front hoof of the southern constellation Centaurus. Image credit: Sky and Telescope.
With a declination of -60, Alpha Centauri is only visible to observes south of 30 degrees N. It marks a front hoof of the Centaur Chiron, the “good” centaur.
*G-type dwarf (luminosity class V) stars have an effective temperature of 5,300–6,000 K. a mass within the range of 0.8 – 1.04 solar masses; and a radius between 0.96 – 1.15 solar radii, inclusive.
2nd: Tau Ceti
Distance: 11.9 light years from the Sun
Tau Ceti is classified as a G8V star, meaning that it is slightly cooler than the Sun (effective temperature around 5,300 K.) Although Tau Ceti is 80% as massive as the Sun, it is half its size in terms of volume and also half as luminous. With an apparent magnitude of 3.5, it appears 96 times dimmer than Sirius and is therefore visible in darker (little or no light pollution) skies.
Tau Ceti is the star that marks the left edge of the southernmost starline within the constellation Cetus the Whale. Deneb Kaitos (Betsa Ceti) marks the right edge. Image credit: Sky and Telescope.
With a declination of almost -16, Tau Ceti is visible to all observers south of 74 degrees N. It marks part of the underside of Cetus the whale (or seamonster.)
3rd: 82 G Eridani
Distance: 19.7 light years from the Sun
The faint naked eye star 82 G Eridani is classified as G6V, meaning that its approximate effective temperature of 5,470 K is only slightly lower than the Sun’s. With both a mass and a volume 80% that of the Sun, it is only about 69% as luminous. With an apparent magnitude of 4.3, 82 G Eridani is about 200 times dimmer than Sirius and can only be found in the darkest skies.
82 G Eridani is represented by a black dot just down to the lower left of theta Eridani. (Also, if you extend the “l” in Horologium upward, it will interesct with 82 G Eridani and it passes through the rectilinear region defined by Eridanus.) Image credit: Torsten Bronger.
With a declination of -43 degrees, 82 G Eridani is only visible to observers south of 47 degrees North. it is not actually part of the Eridanus constellation pattern. Instead, it is located with the rectilinear region surrounding the Eridanus pattern and is therefore considered to within Eridanus.
Considering that 7.6% of all main sequence stars are G-types, we’d expect slightly less than handful of such stars within the closest hundred, which is conveniently consistent with our findings.
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