HD 204018
HD 204018, also designated as HR 8202, is a visual binary located in the southern constellation Microscopium. The primary has an apparent magnitude of 5.58, making it faintly visible to the naked eye under ideal conditions. The companion has an apparent magnitude of 8.09. The system is located relatively close at a distance of 176 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of . At its current distance, HD 204018's combined brightness is diminished by 0.13 magnitudes due to interstellar dust. HD 204018A is an Am star with a stellar classification of kA4hF0 VmF6, indicating that it has the calcium K-line of an A4 star, the hydrogen lines of a F0 main-sequence star and the metallic lines of a F6 star. It has 1.65 times the mass of the Sun and 2.55 times the Sun's radius. It radiates 15 times the luminosity of the Sun from its photosphere at an effective temperature of , giving it a yellowish-white hue. At an age of 1.5 billion years, HD 2014018A is estimated to be on the subgiant branch. An alternate model places it on the main sequence at an age of 1,35 billion years. The object spins at a moderate speed with a projected rotational velocity of . The companion is an F8 main sequence star located " away along a position angle of 151°. It has an angular diameter of , which yields a radius of  at its estimated distance. It has 102% times the mass of the Sun and an effective temperature of . HD 204018B is estimated to be 3.46 billion years old and is slightly metal deficent. There is a magnitude 12 co-moving companion located 295.3" away from the system along a position angle of 75°. It is a red dwarf with an estimated spectral class of K6 and any orbit would take over a million years. References

Binary stars
A-type subgiants
Am stars
F-type main-sequence stars
Microscopium
Microscopii, 69
CD-43 14539
204018
105913
8202