Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Delphinus |
Right ascension | 20h 28m 18.6367s [1] |
Declination | +18° 46′ 10.180″ [1] |
Apparent magnitude (V) | 6.97 + 10.60 [2] |
Characteristics | |
Spectral type | G1V [3] + K3: [4] |
B−V color index | 0.662±0.007 [5] |
Astrometry | |
Radial velocity (Rv) | −91.290±0.0039 [6] km/s |
Proper motion (μ) |
RA: 349.620(16)
mas/
yr
[1] Dec.: −56.618(19) mas/ yr [1] |
Parallax (π) | 26.6465 ± 0.0225 mas [1] |
Distance | 122.4 ± 0.1
ly (37.53 ± 0.03 pc) |
Absolute magnitude (MV) | 4.01 [5] |
Details [7] | |
HD 195019 A | |
Mass | 1.08±0.01 [8] M☉ |
Radius | 1.47±0.04 [8] R☉ |
Luminosity | 2.23±0.02 [8] L☉ |
Surface gravity (log g) | 4.13±0.02 [8] cgs |
Temperature | 5,825±56 [8] K |
Metallicity [Fe/H] | 0.068±0.030 [9] dex |
Rotational velocity (v sin i) | 2.47±0.50 [9] km/s |
Age | 7.7±0.7 [8] Gyr |
HD 195019 B | |
Mass | 0.7 [10] M☉ |
Surface gravity (log g) | 4.46 [11] cgs |
Temperature | 4,652 [11] K |
Rotational velocity (v sin i) | 1.71 [11] km/s |
Other designations | |
Database references | |
SIMBAD | data |
HD 195019 is a binary star system in the northern constellation of Delphinus. The brighter star has a close orbiting exoplanet companion. This system is located at a distance of 122 light years from the Sun based on parallax measurements, [1] but it is drifting closer with a radial velocity of −91.3 km/s. [6] Although it has an absolute magnitude of 4.01, [5] at that distance the system is considered too faint to be viewed with the naked eye, having a combined apparent visual magnitude of 6.87. [5] However, it should be readily visible with a pair of binoculars or a small telescope. [13]
The spectrum of the primary member, designated component A, presents as a G-type main-sequence star with a stellar classification of G1V. [3] An older stellar classification of G3 V/IV [14] suggested it may be near the end of its main sequence lifespan and is evolving into a subgiant star. [13] This is an older star with an estimated age of nearly 8 [8] billion years and a low level of magnetic activity in its chromosphere. [8] The abundance of iron is near solar. [9] The star has a mass similar to the Sun but a larger radius. It is radiating 2.23 times the luminosity of the Sun from its photosphere at an effective temperature of 5,825 K. [8]
The co-moving companion, component B, was first reported by G. W. Hough in 1881. As of 2016, it is located at an angular separation of 3.40 ″ along a position angle of 334° relative to the primary. [2] This corresponds to a projected separation of 131 AU. This is a K-type star with 70% of the mass of the Sun [10] and is magnitude 10.60. [2]
In 1998, a planet was discovered at Lick Observatory utilizing a radial velocity method, orbiting around Star HD 195019 A. [14] A search of astrometric observations from Hipparcos suggested this may be a stellar object in a near polar orbit. [15] [16] [13] However, interferometric observations ruled out a stellar companion in this orbit with high likelihood. [17]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | >3.69 ± 0.30 MJ | 0.1388 ± 0.0080 | 18.20132 ± 0.00039 | 0.0138 ± 0.0044 | — | — |
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Delphinus |
Right ascension | 20h 28m 18.6367s [1] |
Declination | +18° 46′ 10.180″ [1] |
Apparent magnitude (V) | 6.97 + 10.60 [2] |
Characteristics | |
Spectral type | G1V [3] + K3: [4] |
B−V color index | 0.662±0.007 [5] |
Astrometry | |
Radial velocity (Rv) | −91.290±0.0039 [6] km/s |
Proper motion (μ) |
RA: 349.620(16)
mas/
yr
[1] Dec.: −56.618(19) mas/ yr [1] |
Parallax (π) | 26.6465 ± 0.0225 mas [1] |
Distance | 122.4 ± 0.1
ly (37.53 ± 0.03 pc) |
Absolute magnitude (MV) | 4.01 [5] |
Details [7] | |
HD 195019 A | |
Mass | 1.08±0.01 [8] M☉ |
Radius | 1.47±0.04 [8] R☉ |
Luminosity | 2.23±0.02 [8] L☉ |
Surface gravity (log g) | 4.13±0.02 [8] cgs |
Temperature | 5,825±56 [8] K |
Metallicity [Fe/H] | 0.068±0.030 [9] dex |
Rotational velocity (v sin i) | 2.47±0.50 [9] km/s |
Age | 7.7±0.7 [8] Gyr |
HD 195019 B | |
Mass | 0.7 [10] M☉ |
Surface gravity (log g) | 4.46 [11] cgs |
Temperature | 4,652 [11] K |
Rotational velocity (v sin i) | 1.71 [11] km/s |
Other designations | |
Database references | |
SIMBAD | data |
HD 195019 is a binary star system in the northern constellation of Delphinus. The brighter star has a close orbiting exoplanet companion. This system is located at a distance of 122 light years from the Sun based on parallax measurements, [1] but it is drifting closer with a radial velocity of −91.3 km/s. [6] Although it has an absolute magnitude of 4.01, [5] at that distance the system is considered too faint to be viewed with the naked eye, having a combined apparent visual magnitude of 6.87. [5] However, it should be readily visible with a pair of binoculars or a small telescope. [13]
The spectrum of the primary member, designated component A, presents as a G-type main-sequence star with a stellar classification of G1V. [3] An older stellar classification of G3 V/IV [14] suggested it may be near the end of its main sequence lifespan and is evolving into a subgiant star. [13] This is an older star with an estimated age of nearly 8 [8] billion years and a low level of magnetic activity in its chromosphere. [8] The abundance of iron is near solar. [9] The star has a mass similar to the Sun but a larger radius. It is radiating 2.23 times the luminosity of the Sun from its photosphere at an effective temperature of 5,825 K. [8]
The co-moving companion, component B, was first reported by G. W. Hough in 1881. As of 2016, it is located at an angular separation of 3.40 ″ along a position angle of 334° relative to the primary. [2] This corresponds to a projected separation of 131 AU. This is a K-type star with 70% of the mass of the Sun [10] and is magnitude 10.60. [2]
In 1998, a planet was discovered at Lick Observatory utilizing a radial velocity method, orbiting around Star HD 195019 A. [14] A search of astrometric observations from Hipparcos suggested this may be a stellar object in a near polar orbit. [15] [16] [13] However, interferometric observations ruled out a stellar companion in this orbit with high likelihood. [17]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | >3.69 ± 0.30 MJ | 0.1388 ± 0.0080 | 18.20132 ± 0.00039 | 0.0138 ± 0.0044 | — | — |