HD 195019
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus |
| A | |
| Right ascension | 20h 28m 18.6367s |
| Declination | +18° 46′ 10.180″ |
| Apparent magnitude (V) | 6.97 |
| B | |
| Right ascension | 20h 28m 18.5185s |
| Declination | +18° 46′ 13.365″ |
| Apparent magnitude (V) | 10.60 |
| Characteristics | |
| Spectral type | G1V + K3: |
| B−V color index | 0.662±0.007 |
| Astrometry | |
| Absolute magnitude (MV) | +4.01 |
| A | |
| Radial velocity (Rv) | −91.290±0.0039 km/s |
| Proper motion (μ) | RA: +349.620(16) mas/yr Dec.: −56.618(19) mas/yr |
| Parallax (π) | 26.6465±0.0225 mas |
| Distance | 122.4 ± 0.1 ly (37.53 ± 0.03 pc) |
| B | |
| Proper motion (μ) | RA: +361.063(18) mas/yr Dec.: −65.735(23) mas/yr |
| Parallax (π) | 26.6192±0.0251 mas |
| Distance | 122.5 ± 0.1 ly (37.57 ± 0.04 pc) |
| Details | |
| HD 195019 A | |
| Mass | 1.08±0.01 M☉ |
| Radius | 1.47±0.04 R☉ |
| Luminosity | 2.23±0.02 L☉ |
| Surface gravity (log g) | 4.13±0.02 cgs |
| Temperature | 5,825±56 K |
| Metallicity [Fe/H] | 0.068±0.030 dex |
| Rotation | 25 days |
| Rotational velocity (v sin i) | 2.47±0.50 km/s |
| Age | 7.7±0.7 Gyr |
| HD 195019 B | |
| Mass | 0.7 M☉ |
| Radius | 0.62 R☉ |
| Luminosity | 0.10 L☉ |
| Surface gravity (log g) | 4.46 cgs |
| Temperature | 4,652 K |
| Rotational velocity (v sin i) | 1.71 km/s |
| Other designations | |
| BD+18°4505, HD 195019, HIP 100970, SAO 106138, WDS J20283+1846, LTT 15981, NLTT 49312, GCRV 12790, 2MASS J20281860+1846103 | |
| 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, but it is drifting closer with a radial velocity of −91.3 km/s. Although it has an absolute magnitude of 4.01, 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. However, it should be readily visible with a pair of binoculars or a small telescope.
The spectrum of the primary member, designated component A, presents as a G-type main-sequence star with a stellar classification of G1V. An older stellar classification of G3 V/IV suggested it may be near the end of its main sequence lifespan and is evolving into a subgiant star. This is an older star with an estimated age of nearly 8 billion years and a low level of magnetic activity in its chromosphere. The abundance of iron is near solar. 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.
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. This corresponds to a projected separation of 131 AU. This is a K-type star with 70% of the mass of the Sun and is magnitude 10.60.