Iota Andromedae
Iota Andromedae, also named Rasalnaqa, is a single star in the northern constellation of Andromeda. It has the Flamsteed designation 17 Andromedae, while Iota Andromedae is the Bayer designation as Latinized from ι Andromedae. This object is visible to the naked eye at night as a faint, blue-white hued star with an apparent visual magnitude of +4.29. Based upon parallax measurements, it is located approximately 510 light years distant from the Sun.
This object is a B-type main-sequence star with a stellar classification of B8 V. It is among the least variable stars observed during the Hipparcos mission. The star is 116 million years old with 3.1 times the mass of the Sun and is spinning with a projected rotational velocity of 70 km/s. It is radiating 638 times the luminosity of the Sun from its photosphere at an effective temperature of 12,620 K. The star is somewhat metal-poor, although the abundance of helium is close to solar. The latter excludes it from membership among the class of peculiar stars. Iota Andromedae is a debris disk candidate, showing an infrared excess at a wavelength of 18 μm.
Name
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Keff al-Salsalat, which was translated into Latin as Manus Catenata, meaning hand of the chained woman. This name originally referred to a group of three stars – ι Andromedae, κ Andromedae, and λ Andromedae – also known in traditional Arabic astronomy as Ra’s al-Nāqa, the head of the she-camel. The IAU Working Group on Star Names approved the name Rasalnaqa for ι Andromedae on 8 May 2025 and it is now so entered in the IAU Catalog of Star Names; the name Kaffalmusalsala was given to κ Andromedae.In Chinese, 螣蛇, meaning Flying Serpent, refers to an asterism consisting of ι Andromedae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae and ψ Andromedae. Consequently, the Chinese name for ι Andromedae itself is 螣蛇二十二.