Sun's radius in the context of "51 Ophiuchi"

Canopus is the brightest star in the southern constellation of Carina and the second-brightest star in the night sky. It is designated α Carinae, which is romanized (transliterated) to Alpha Carinae. With a visual apparent magnitude of −0.74, it is outshone only by Sirius.

Located around 310 light-years from the Sun, Canopus is a bright giant of spectral type A9, so it is essentially white when seen with the naked eye. It has a luminosity over 10,000 times the luminosity of the Sun, is nine to ten times as massive, and has expanded to 71 times the Sun's radius. Its enlarged photosphere has an effective temperature of around 7400 K. Canopus is undergoing core helium burning and is currently in the so-called blue loop phase of its evolution, having already passed through the red-giant branch after exhausting the hydrogen in its core. Canopus is a source of X-rays, which are likely being emitted from its corona.

HD 202628 is a single star in the southern constellation of Microscopium. It has an apparent visual magnitude of +6.7, which makes it too faint to be readily visible to the naked eye. The star is located at a distance of 77.6 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +12.1 km/s. The absolute magnitude of this star is 4.86.

The stellar classification of HD 202628 is G1.5V, matching a yellow-hued G-type main-sequence star similar to the Sun. The chromospheric activity level and amount of X-ray emission is consistent with a star that is younger than the Sun. It is spinning with a projected rotational velocity of 2.6 km/s. The star has 107% of the mass of the Sun and 95% of the Sun's radius. The metallicity, or abundance of heavier elements, appears to be about the same as in the Sun. It is radiating 95% of the luminosity of the Sun from its photosphere at an effective temperature of 5,843 K.

ν Serpentis, Latinized as Nu Serpentis, is a solitary star in the Serpens Cauda section of the equatorial constellation of Serpens. It is a white-hued star that is faintly visible to the naked eye with an apparent visual magnitude of 4.32. Based upon an annual parallax shift of 16.05 mas as seen from the Sun, it is about 203 light years from the Sun. The star is drifting further away with a radial velocity of +5 km/s.

This is an A-type main-sequence star with a stellar classification of A2V, and is generating energy through hydrogen fusion at its core. It is 350 million years old with a high rate of spin, showing a projected rotational velocity of 123 km/s. The star has 2.64 times the mass of the Sun and 3.0 times the Sun's radius. It is radiating 76 times the Sun's luminosity from its photosphere at an effective temperature of 9,120 K. Nu Serpentis has an optical companion, a magnitude +9.4 star at an angular separation of 46 arcseconds.

5 Vulpeculae is a single, white-hued star in the northern constellation of Vulpecula. It is situated amidst a random concentration of bright stars designated Collinder 399, or Brocchi's Cluster. This is a faint star that is just visible to the naked eye with an apparent visual magnitude of 5.60. Based upon an annual parallax shift of 13.8921±0.0900 mas, it is located around 235 light years from the Sun. It is moving closer with a heliocentric radial velocity of −21 km/s, and will make its closest approach in 2.5 million years at a separation of around 120 ly (36.89 pc).

This is a young A-type main-sequence star with a stellar classification of A0 V. It is a rapidly rotating star with a projected rotational velocity of 154 km/s. The star has an estimated 2.33 times the mass of the Sun and about 2.7 times the Sun's radius. It is radiating 34 times the Sun's luminosity from its photosphere at an effective temperature of 8,940 K.

HD 134060, also known by its Gould designation of 38 G. Circini, is a star in the southern constellation of Circinus. It is near the lower limit of stars visible to the naked eye, having an apparent visual magnitude of 6.29. The distance to HD 134060, as determined using an annual parallax shift measurement of 41.6 mas, is 78.4 light years. It is moving further away with a heliocentric radial velocity of 43.5 km/s, having come within 34.6 ly some 439,000 years ago.

During the NStars project, Grey et al. (2006) found a stellar classification of G0 V Fe+0.4 for this star, matching a Sun-like G-type main-sequence star with an overabundance of iron in its outer atmosphere. However, an older classification of G3 IV is still used, which would suggest it is instead a more evolved subgiant star. HD 134060 has an estimated 1.07 times the mass of the Sun and 1.15 times the Sun's radius. It is radiating 1.63 times the Sun's luminosity from its photosphere at an effective temperature of about 5,965 K.