Iota Andromedae
Star in the constellation of Andromeda
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Iota Andromedae, also named Rasalnaqa,[13] is a single[14] 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.[2] Based upon parallax measurements, it is located approximately 510 light years distant from the Sun.[1]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 23h 38m 08.200s[1] |
| Declination | +43° 16â² 05.06â³[1] |
| Apparent magnitude (V) | +4.29[2] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B8 V[3][4] |
| UâB color index | â0.29[5] |
| BâV color index | â0.11[5] |
| Variable type | constant[6] |
| Astrometry | |
| Radial velocity (Rv) | â0.5[2] km/s |
| Proper motion (μ) | RA: +27.163 mas/yr[1] Dec.: â1.246 mas/yr[1] |
| Parallax (Ï) | 6.4313±0.1375 mas[1] |
| Distance | 510 ± 10 ly (155 ± 3 pc) |
| Absolute magnitude (MV) | â1.63[7] |
| Details | |
| Mass | 3.1 Mâ[4] 3.98±0.06[8] Mâ |
| Radius | 4.6[9] Râ |
| Luminosity | 638[7] Lâ |
| Surface gravity (log g) | 3.35[6] cgs |
| Temperature | 12,620[10] K |
| Metallicity [Fe/H] | â0.19±0.14[6] dex |
| Rotational velocity (v sin i) | 70[11] km/s |
| Age | 116[4] Myr |
| Other designations | |
| Rasalnaqa, ι And, 17 And, BD+42°4720, FK5 891, HD 222173, HIP 116631, HR 8965, SAO 53216, PPM 64473[12] | |
| Database references | |
| SIMBAD | data |
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.[6] The star is 116[4] million years old with 3.1[4] times the mass of the Sun and is spinning with a projected rotational velocity of 70 km/s.[11] It is radiating 638[7] times the luminosity of the Sun from its photosphere at an effective temperature of 12,620 K.[10] 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.[6] Iota Andromedae is a debris disk candidate, showing an infrared excess at a wavelength of 18 μm.[15]
Name
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Keff al-Salsalat (Ù٠اÙ٠سÙسÙØ© - kaf al-musalsala), which was translated into Latin as Manus Catenata, meaning hand of the chained woman (i.e. Andromeda).[16] This name originally referred to a group of three stars â ι Andromedae, κ Andromedae, and λ Andromedae â also known in traditional Arabic astronomy as Raâs al-NÄqa, the head of the she-camel.[17] 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.[13]
In Chinese, è£è (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of ι Andromedae, α Lacertae, 4 Lacertae, Ï2 Cygni, Ï1 Cygni, HD 206267, ε Cephei, β Lacertae, Ï Cassiopeiae, Ï Cassiopeiae, Ï Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae and Ï Andromedae. Consequently, the Chinese name for ι Andromedae itself is è£èäºåäº (Téng Shé èrshÃèr, English: the Twenty Second Star of Flying Serpent).[18]