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Location of Theta Aquilae to the left of center |
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| Observation data Epoch J2000 Equinox J2000 |
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|---|---|
| Constellation | Aquila |
| Right ascension | 20h 11m 18.2855s |
| Declination | -00° 49′ 17.26″ |
| Apparent magnitude (V) | 3.242 |
| Characteristics | |
| Spectral type | B9.5III |
| U−B color index | -0.14 |
| B−V color index | -0.07 |
| Astrometry | |
| Radial velocity (Rv) | -27.3 km/s |
| Proper motion (μ) | RA: 35.48 mas/yr Dec.: 6.05 mas/yr |
| Parallax (π) | 11.36 ± 0.92 mas |
| Distance | 290 ± 20 ly (88 ± 7 pc) |
| Absolute magnitude (MV) | -1.48 |
| Details | |
| Mass | 3.7 M☉ |
| Radius | 5.5 R☉ |
| Luminosity | 370 L☉ |
| Temperature | 10,800 K |
| Rotation | 63 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Database references | |
| SIMBAD | data |
Theta Aquilae (θ Aql, θ Aquilae) is a binary star in the constellation Aquila. It is approximately 287 light years from Earth. It has the traditional name Tseen Foo, which is derived from the Mandarin 天桴 tiānfú meaning "the heavenly raft(er)"; it may also mean drumsticks, with Altair, Beta Aquilae and Gamma Aquilae being the drum.
In Chinese, 天桴 (Tiān Fú), meaning Celestial Drumstick, refers to an asterism consisting of θ Aquilae, 62 Aquilae, 58 Aquilae and η Aquilae.[1] Consequently, θ Aquilae itself is known as 天桴一 (Tiān Fú yī, English: the First Star of Celestial Drumstrick.)[2]
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Thanih Ras al Akab (تاني ألرأس ألعقاب - taanii al ra’s alʕuqāb), which was translated into Latin as Secunda Capitis Vulturis, meaning the second (star) of eagle's head.[3]
This star, along with δ Aql (Denebokab) and η Aql, were Al Mizān (ألميزان), the Scale-beam.[4]. According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Mizān were the title for three stars :δ Aql as Al Mizān I, η Aql as l Mizān II and θ Aql as Al Mizān III[5]
Theta Aquilae is a spectroscopic binary classified as a blue-white B-type giant with an apparent magnitude of +3.24. The binary has an orbital period of 17.123 days.
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