Delta Andromedae

Delta Andromedae (δ And, δ Andromedae) is a multiple star system in the northern constellation of Andromeda. Based upon parallaxmeasurements, it is located at a distance of approximately 105.5 light-years (32.3 parsecs) from the Earth.

In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of δ Andromedae, η Andromedae, 65 Piscium, ζ Andromedae, ι Piscium, ε Andromedae,  π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, the Chinese name for δ Andromedae itself is 奎宿五 (Kuí Sù wǔ, English: the Fifth Star of Legs.)[13] Apart from its Bayer designation, it was also given the title Delta by Elijah H. Burritt in his star atlas.[14]

This is a long-period spectroscopic binary with an orbital period of approximately 15,000 days (41 years) and an overall apparent visual magnitude of approximately 3.28. The primary of the spectroscopic binary has a stellar classification of K3 III, indicating that it is a giant star.[5][7]It most likely evolved from a F-type main sequence star after consuming the hydrogen at its core.[11] The secondary is a relatively faint K-type dwarf, which has been imaged using a stellar coronagraph.[15] The star has two optical companions, the closest of which may be an orbiting red dwarf of class M3 with a separation of at least 900 astronomical units.[16]

An excess of infrared emission from δ Andromedae suggested that it may be surrounded by a shell of dust.[3] In 2003 it was determined that this is more likely a circumstellar debris disk.