HD 42936
HD 42936, also known as DMPP-3, is a star located in the southern circumpolar constellation Mensa. With an apparent magnitude of 9.1, it is too faint to be detected with the naked eye but can be seen with a telescope. The star is relatively close at a distance of about 153 light-years (47 parsecs) but is receding with a heliocentric radial velocity of 35.6 km/s.
Location of HD 42936 in the night sky. The star is marked within the red diamond. | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Mensa |
| Right ascension | 06h 06m 29.84725s |
| Declination | −72° 30′ 45.5674″ |
| Apparent magnitude (V) | 9.10 |
| Characteristics | |
| HD 42936A | |
| Evolutionary stage | main sequence star |
| Spectral type | K0 IV/V |
| B−V color index | +0.91 |
| HD 42936B | |
| Evolutionary stage | main sequence star |
| Spectral type | L |
| Astrometry | |
| Radial velocity (Rv) | 35.64±0.49 km/s |
| Proper motion (μ) | RA: −0.716 mas/yr Dec.: −382.755 mas/yr |
| Parallax (π) | 21.2496 ± 0.1143 mas |
| Distance | 153.5 ± 0.8 ly (47.1 ± 0.3 pc) |
| Absolute magnitude (MV) | 5.78 |
| Orbit | |
| Primary | HD 42936A |
| Companion | HD 42936B |
| Period (P) | 506.89±0.01 d |
| Semi-major axis (a) | 1.139±0.004 AU |
| Eccentricity (e) | 0.596±0.001 |
| Inclination (i) | 63.89±0.78° |
| Argument of periastron (ω) (secondary) | 158.88+0.03 −0.01° |
| Semi-amplitude (K1) (primary) | 2.65731+0.00033 −0.00002 km/s |
| Details | |
| HD 42936A | |
| Mass | 0.900±0.009 M☉ |
| Radius | 0.861±0.005 R☉ |
| Luminosity | 0.510±0.003 L☉ |
| Surface gravity (log g) | 4.266±0.045 cgs |
| Temperature | 5,201±20 K |
| Metallicity [Fe/H] | 0.147±0.013 dex |
| Rotation | 21.8+0.5 −16.5 d |
| Rotational velocity (v sin i) | 3.17±0.1 km/s |
| Age | 9.6±0.8 Gyr |
| HD 42936B | |
| Mass | 91.90±0.85 MJup |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 42936 is an early K-type star with the blended luminosity class of a main sequence star and a subgiant. At present it has 87% the mass of the Sun and 91% the radius of the Sun. The object shines at 51% the luminosity of the Sun from its photosphere at an effective temperature of 5,138 K, which gives it an orangish yellow glow. HD 42936 has iron abundance 151% that of the Sun, meaning it is metal enriched despite an age of 10.9 billion years.
HD 42936 has a very low mass companion star in a close orbit, approaching to 0.498 AU at periastron.