Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hercules |
Right ascension | 17h 55m 25.18845s [1] |
Declination | 26° 02′ 59.9701″ [1] |
Apparent magnitude (V) | (5.34 - 5.54 [2]) |
Characteristics | |
Evolutionary stage | post-AGB |
Spectral type | F2Ibe [3] |
U−B color index | −0.34 [4] |
B−V color index | +0.34 [4] |
Variable type | SRd [2] |
Astrometry | |
Radial velocity (Rv) | −28.5 [5] km/s |
Proper motion (μ) |
RA: 3.894
[1]
mas/
yr Dec.: 5.193 [1] mas/ yr |
Parallax (π) | 0.6893 ± 0.0718 mas [1] |
Distance | approx. 4,700
ly (approx. 1,500 pc) |
Absolute magnitude (MV) | −6.5 [6] |
Details | |
89 Her A | |
Mass | 1.0 [7] M☉ |
Radius | 71.0 [7] R☉ |
Luminosity | 8,350 [7] L☉ |
Surface gravity (log g) | 0.55 [3] cgs |
Temperature | 6,550 [3] K |
Metallicity | −0.5 [3] |
Rotational velocity (v sin i) | 23 [8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
89 Herculis is a binary star system located about 4,700 light years away from the Sun in the northern constellation of Hercules. It is visible to the naked eye as a faint, fifth magnitude star. The system is moving closer to the Earth with a heliocentric radial velocity of −28.5 km/s. [5]
This is a spectroscopic binary with the pair surrounded by a dusty disc, and an hourglass-shaped nebula formed from outflowing gas. [10] The mass of the nebula is about 0.018 M☉, of which a majority is in the outflow. [10] The system shows variable brightness and spectral line profiles. [11] The companion has a very low mass and luminosity and orbits the primary in 288 days. [3]
The primary component has a stellar classification of F2Ibe, [3] and is among a rare class of post- asymptotic giant branch stars – low-mass stars in the last stages of their lives, highly inflated to appear as supergiants. [3] It is classified as a semiregular variable star, subtype SRd, and ranges from magnitude 5.3 down to 5.5 over a period of around 68 days. [2] The star has expanded to 71 [7] times the Sun's radius and is radiating 8,350 [7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 6,550 K. [3]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hercules |
Right ascension | 17h 55m 25.18845s [1] |
Declination | 26° 02′ 59.9701″ [1] |
Apparent magnitude (V) | (5.34 - 5.54 [2]) |
Characteristics | |
Evolutionary stage | post-AGB |
Spectral type | F2Ibe [3] |
U−B color index | −0.34 [4] |
B−V color index | +0.34 [4] |
Variable type | SRd [2] |
Astrometry | |
Radial velocity (Rv) | −28.5 [5] km/s |
Proper motion (μ) |
RA: 3.894
[1]
mas/
yr Dec.: 5.193 [1] mas/ yr |
Parallax (π) | 0.6893 ± 0.0718 mas [1] |
Distance | approx. 4,700
ly (approx. 1,500 pc) |
Absolute magnitude (MV) | −6.5 [6] |
Details | |
89 Her A | |
Mass | 1.0 [7] M☉ |
Radius | 71.0 [7] R☉ |
Luminosity | 8,350 [7] L☉ |
Surface gravity (log g) | 0.55 [3] cgs |
Temperature | 6,550 [3] K |
Metallicity | −0.5 [3] |
Rotational velocity (v sin i) | 23 [8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
89 Herculis is a binary star system located about 4,700 light years away from the Sun in the northern constellation of Hercules. It is visible to the naked eye as a faint, fifth magnitude star. The system is moving closer to the Earth with a heliocentric radial velocity of −28.5 km/s. [5]
This is a spectroscopic binary with the pair surrounded by a dusty disc, and an hourglass-shaped nebula formed from outflowing gas. [10] The mass of the nebula is about 0.018 M☉, of which a majority is in the outflow. [10] The system shows variable brightness and spectral line profiles. [11] The companion has a very low mass and luminosity and orbits the primary in 288 days. [3]
The primary component has a stellar classification of F2Ibe, [3] and is among a rare class of post- asymptotic giant branch stars – low-mass stars in the last stages of their lives, highly inflated to appear as supergiants. [3] It is classified as a semiregular variable star, subtype SRd, and ranges from magnitude 5.3 down to 5.5 over a period of around 68 days. [2] The star has expanded to 71 [7] times the Sun's radius and is radiating 8,350 [7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 6,550 K. [3]