HD 193721
HD 193721 (HR 7785) is an astrometric binary in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.77, allowing it to be faintly seen with the naked eye. Parallax measurements place the system 760 light years away from the Solar System and it is currently receding with a heliocentric radial velocity . HD 193721 has a stellar classification of G6/8 II — intermediate between a G6 and 8 bright giant. At present it has 3.49 times the mass of the Sun, but has expanded to 24.4 times its girth. It shines with a luminosity of  from its enlarged photosphere at an effective temperature of , giving a yellow hue. HD 193721 is metal deficent with an iron abundance 71% that of the Sun and spins leisurely with a projected rotational velocity of . The system has an companion designated CPD −81°900. The object has a spectral classification of F8 and is located  along a position angle of  (as of 1998). CPD −81°900 is a foreground object, having a higher parallax and different proper motion. References

G-type bright giants
Octans
Astrometric binaries
Double stars
193721
PD-81 00901
101427
7785
Octantis, 47