HD 156279
Star in the constellation Draco
From Wikipedia, the free encyclopedia
HD 156279 is a star with a pair of orbiting exoplanets[9] located in the northern constellation of Draco.[1] It has various alternate designations, including HIP 84171 and BD+63 1335. Parallax measurements yield a distance of 118 light years from the Sun,[2] but it is drifting closer with a radial velocity of −20 km/s.[5] Despite an absolute magnitude of 5.25,[1] at that distance the star is too faint to be visible to the naked eye with an apparent visual magnitude of 8.17.[3] It is presumed to be a single star, as in 2019 all imaging surveys have failed to find any stellar companions.[3]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco[1] |
| Right ascension | 17h 12m 23.204816s[2] |
| Declination | +63° 21′ 07.531205″[2] |
| Apparent magnitude (V) | 8.167±0.013[3] |
| Characteristics | |
| Evolutionary stage | main-sequence[4] |
| Spectral type | K0[3] or G6[4] |
| Apparent magnitude (R) | 7.60[1] |
| Apparent magnitude (G) | 7.8657[2] |
| Apparent magnitude (J) | 6.677±0.018[1] |
| B−V color index | 0.801±0.014[1] |
| Astrometry | |
| Radial velocity (Rv) | −20.144±0.161[5] km/s |
| Proper motion (μ) | RA: −1.879±0.024 mas/yr[2] Dec.: 160.429±0.027 mas/yr[2] |
| Parallax (π) | 27.6756±0.0200 mas[2] |
| Distance | 117.85 ± 0.09 ly (36.13 ± 0.03 pc) |
| Absolute magnitude (MV) | 5.25[1] |
| Details | |
| Mass | 0.999+0.046 −0.045[6] M☉ |
| Radius | 0.94±0.02[7] R☉ |
| Luminosity | 0.70±0.01[7] L☉ |
| Surface gravity (log g) | 4.45±0.03[7] cgs |
| Temperature | 5,449±31[7] K |
| Metallicity [Fe/H] | 0.14±0.01[3] dex |
| Rotational velocity (v sin i) | 2.51±1[4] km/s |
| Age | 7.4±2.2[7] Gyr |
| Other designations | |
| BD+63 1335, HD 156279, HIP 84171, SAO 17390, PPM 20265, NLTT 44404, TYC 4202-656-1, 2MASS J17122319+6321074, Gaia DR2 1631084478574318976[8] | |
| Database references | |
| SIMBAD | data |
The spectrum of HD 156279 has a stellar classification of G6[4] or K0,[3] depending on the study. Hence it presents as an ordinary main sequence star[4] of the late G-type or early K-type. The star has 93% of the mass of the Sun and 94% of the Sun's radius. HD 156279 is roughly seven[7] billion years old and is spinning with a projected rotational velocity of 2.5 km/s.[4] Based on the abundance of iron, this star is slightly enriched in heavy elements, having 140% of the solar abundance.[3] It is radiating 70%[7] of the luminosity of the Sun from its photosphere at an effective temperature of 5,449 K.[7]
Planetary system
Orbiting HD 156279 are two superjovian planets, the inner HD 156279 b (discovered in 2011)[4] and outer HD 156279 c (discovered in 2016).[9] In 2022, the inclination and true mass of HD 156279 c were measured for the first time, using the astrometry technique.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 9.82±0.29 MJ | 0.5126+0.0077 −0.0078 |
0.365235(10) | 0.6479+0.00070 −0.00077 |
— | — |
| c | 10.53+0.65 −0.59 MJ |
5.570+0.086 −0.084 |
13.093±0.081 | 0.2602+0.0047 −0.0048 |
110.9+6.9 −9.4° |
— |