Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 22h 25m 16.62285s [1] |
Declination | +01° 22′ 38.6346″ [1] |
Apparent magnitude (V) | 4.42 - 4.87 [2] |
Characteristics | |
Spectral type | B1III-IVe [3] |
U−B color index | −0.98 [4] |
B−V color index | −0.03 [4] |
Variable type | γ Cas [2] |
Astrometry | |
Radial velocity (Rv) | +4.0 [5] km/s |
Proper motion (μ) |
RA: +17.83
[1]
mas/
yr Dec.: +2.41 [1] mas/ yr |
Parallax (π) | 4.17 ± 0.28 mas [1] |
Distance | 780 ± 50
ly (240 ± 20 pc) |
Absolute magnitude (MV) | −2.09 [6] |
Orbit [7] | |
Period (P) | 84.07±0.02 d |
Semi-major axis (a) | ≥ 0.96 AU |
Eccentricity (e) | 0.0 (fixed) |
Periastron epoch (T) | 2,450,318.5±13.2 JD |
Argument of periastron (ω) (secondary) | 0.0 (fixed)° |
Semi-amplitude (K1) (primary) | 16.7±0.2 km/s |
Semi-amplitude (K2) (secondary) | 101.4±0.2 km/s |
Details | |
A | |
Mass | 10.7±0.7 [8] M☉ |
Radius | 6.2 [9] R☉ |
Luminosity | 7,302 [10] L☉ |
Temperature | 27,094 [9] K |
Metallicity [Fe/H] | −0.02 [6] dex |
Rotational velocity (v sin i) | 215 [11] km/s |
Age | 10.0±5.0 [8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Pi Aquarii, Latinized from π Aquarii, is the Bayer designation for a binary star in the equatorial constellation of Aquarius. This system has an apparent visual magnitude of a mean apparent magnitude of +4.57. [4] Based upon parallax measurements, it is located at a distance of roughly 780 light-years (240 parsecs) from Earth. [1] It is drifting further away with a radial velocity of +4 km/s. [5]
This is a binary star system with an orbital period of 84.1 days. [14] [15] The primary component is a B1 giant or subgiant star. [3] This is a large star with nearly eleven [8] times the mass and over six times the radius of the Sun. [9] Pi Aquarii shines about 7,300 [10] times as brightly as the Sun. This energy is being radiated from its outer atmosphere at an effective temperature of 27,094 K, [9] giving it the blue-hued glow of a B-type star. [16] It is spinning rapidly with a projected rotational velocity of 215 km/s. [11] The nature of the secondary is unknown; some analyses have suggested it is an A- or F-type main-sequence star, [7] but the possibility of a white dwarf has not been ruled out. [17]
Pi Aquarii is notable for having undergone a transition from a Be star (showing hydrogen emission lines) into an ordinary B-type star. [15] It is classified as a Gamma Cassiopeiae type [2] variable star and its brightness varies from magnitude +4.45 to +4.71; a range of 0.28. The dominant variability period, 83.8±0.8 days, is nearly the same as the orbital period. [15] Pi Aquarii has a reasonable chance of becoming a supernova some day. [14]
Pi Aquarii was called Seat /ˈsiːæt/ by Grotius in the 17th century, but the name has rarely been used since. [14]
In Chinese, 墳墓 (Fén Mù), meaning Tomb, refers to an asterism consisting of π Aquarii, γ Aquarii, ζ Aquarii, η Aquarii. [18] Consequently, the Chinese name for π Aquarii itself is 墳墓四 (Fén Mù sì, English: the Fourth Star of Tomb.) [19]
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Wasat al Achbiya (وسط الأخبية - wasath al ahbiyah), which was translated into Latin as Media Tabernaculorum, meaning the middle of luck of the homes (tents). [20] This star, along with γ Aqr (Sadachbia), ζ Aqr (Sadaltager / Achr al Achbiya) and η Aqr (Hydria), were al Aḣbiyah (الأخبية), the Tent. [21] [22] [23]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 22h 25m 16.62285s [1] |
Declination | +01° 22′ 38.6346″ [1] |
Apparent magnitude (V) | 4.42 - 4.87 [2] |
Characteristics | |
Spectral type | B1III-IVe [3] |
U−B color index | −0.98 [4] |
B−V color index | −0.03 [4] |
Variable type | γ Cas [2] |
Astrometry | |
Radial velocity (Rv) | +4.0 [5] km/s |
Proper motion (μ) |
RA: +17.83
[1]
mas/
yr Dec.: +2.41 [1] mas/ yr |
Parallax (π) | 4.17 ± 0.28 mas [1] |
Distance | 780 ± 50
ly (240 ± 20 pc) |
Absolute magnitude (MV) | −2.09 [6] |
Orbit [7] | |
Period (P) | 84.07±0.02 d |
Semi-major axis (a) | ≥ 0.96 AU |
Eccentricity (e) | 0.0 (fixed) |
Periastron epoch (T) | 2,450,318.5±13.2 JD |
Argument of periastron (ω) (secondary) | 0.0 (fixed)° |
Semi-amplitude (K1) (primary) | 16.7±0.2 km/s |
Semi-amplitude (K2) (secondary) | 101.4±0.2 km/s |
Details | |
A | |
Mass | 10.7±0.7 [8] M☉ |
Radius | 6.2 [9] R☉ |
Luminosity | 7,302 [10] L☉ |
Temperature | 27,094 [9] K |
Metallicity [Fe/H] | −0.02 [6] dex |
Rotational velocity (v sin i) | 215 [11] km/s |
Age | 10.0±5.0 [8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Pi Aquarii, Latinized from π Aquarii, is the Bayer designation for a binary star in the equatorial constellation of Aquarius. This system has an apparent visual magnitude of a mean apparent magnitude of +4.57. [4] Based upon parallax measurements, it is located at a distance of roughly 780 light-years (240 parsecs) from Earth. [1] It is drifting further away with a radial velocity of +4 km/s. [5]
This is a binary star system with an orbital period of 84.1 days. [14] [15] The primary component is a B1 giant or subgiant star. [3] This is a large star with nearly eleven [8] times the mass and over six times the radius of the Sun. [9] Pi Aquarii shines about 7,300 [10] times as brightly as the Sun. This energy is being radiated from its outer atmosphere at an effective temperature of 27,094 K, [9] giving it the blue-hued glow of a B-type star. [16] It is spinning rapidly with a projected rotational velocity of 215 km/s. [11] The nature of the secondary is unknown; some analyses have suggested it is an A- or F-type main-sequence star, [7] but the possibility of a white dwarf has not been ruled out. [17]
Pi Aquarii is notable for having undergone a transition from a Be star (showing hydrogen emission lines) into an ordinary B-type star. [15] It is classified as a Gamma Cassiopeiae type [2] variable star and its brightness varies from magnitude +4.45 to +4.71; a range of 0.28. The dominant variability period, 83.8±0.8 days, is nearly the same as the orbital period. [15] Pi Aquarii has a reasonable chance of becoming a supernova some day. [14]
Pi Aquarii was called Seat /ˈsiːæt/ by Grotius in the 17th century, but the name has rarely been used since. [14]
In Chinese, 墳墓 (Fén Mù), meaning Tomb, refers to an asterism consisting of π Aquarii, γ Aquarii, ζ Aquarii, η Aquarii. [18] Consequently, the Chinese name for π Aquarii itself is 墳墓四 (Fén Mù sì, English: the Fourth Star of Tomb.) [19]
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Wasat al Achbiya (وسط الأخبية - wasath al ahbiyah), which was translated into Latin as Media Tabernaculorum, meaning the middle of luck of the homes (tents). [20] This star, along with γ Aqr (Sadachbia), ζ Aqr (Sadaltager / Achr al Achbiya) and η Aqr (Hydria), were al Aḣbiyah (الأخبية), the Tent. [21] [22] [23]