09h56m29.84s, −24° 05′ 57.8″| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h56m 29.844s[1] |
| Declination | –24° 05′ 57.80″[1] |
| Apparent magnitude (V) | 7.93[2] |
| Characteristics | |
| Spectral type | G2V[3] |
| Apparent magnitude (B) | 8.577[2] |
| Apparent magnitude (R) | 7.71[2] |
| Apparent magnitude (J) | 6.839±0.019[2] |
| Apparent magnitude (H) | 6.577±0.034[2] |
| Apparent magnitude (K) | 6.463±0.023[2] |
| B−V color index | 0.647±0.014[2] |
| V−R color index | 0.22[4] |
| Astrometry | |
| Radial velocity (Rv) | +19.56±0.19[4] km/s |
| Proper motion (μ) | RA: –177.127 mas/yr[1] Dec.: +47.099 mas/yr[1] |
| Parallax (π) | 21.9301 ± 0.0267 mas[1] |
| Distance | 148.7 ± 0.2 ly (45.60 ± 0.06 pc) |
| Absolute magnitude (MV) | 4.66[2] |
| Details[5] | |
| Mass | 1.019+0.061 −0.066 M☉ |
| Radius | 1.053+0.026 −0.026 R☉ |
| Luminosity | 1.180+0.036 −0.029 L☉ |
| Surface gravity (log g) | 4.400+0.029 −0.032 cgs |
| Temperature | 5863±88 K |
| Metallicity [Fe/H] | 0.018+0.057 −0.043 dex |
| Rotational velocity (v sin i) | 3.6[6] km/s |
| Age | 4.6+3.7 −2.7 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 86226 is a star with a pair of orbiting exoplanet companions, found in the constellation of Hydra. With an apparent visual magnitude of 7.93,[2] it is too dim to be visible with the naked eye. The distance to this system has been determined by the parallax method, yielding a range of 149 light years. It is receding with a heliocentric radial velocity of +19.6 km/s.[4] A survey in 2015 has ruled out the existence of any stellar companions at projected distances above 12 astronomical units.[8]
This is an ordinary G-type main-sequence star with a stellar classification of G2V.[3] It is similar in size, mass, and composition to the Sun,[5] although it isn't considered a solar twin.[9] The age is about the same; roughly 4.6 billion years old. The star is radiating 18% greater luminosity (compared to the Sun) from its photosphere at an effective temperature of 5,863 K.[5] It is spinning with a projected rotational velocity of 3.6 km/s.[6]
As of 2014[update], Radio emission at a frequency of 150 MHz has been tentatively detected from the proximity of this system, although it is not clear whether the star or a satellite orbiting a rapidly rotating planet is the source.[10]
Due to the periodic spectrum shifts when it had when placed under a Doppler test, 13 Magellan Doppler Velocity observations were made of an object found near the star. The object discovered in 2010 had a Keplerian orbit, was declared an exoplanet and dubbed HD 86226 b.[11] A hot Super-Earth planet called HD 86226 c was discovered in 2020.[5] It may be undergoing considerable atmospheric mass loss.[12]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | 7.25+1.19 −1.12 M🜨 |
0.049±0.001 | 3.98442±0.00018 | 0.075+0.065 −0.048 |
86.45+0.26 −0.16° |
2.16±0.08 R🜨 |
| b | 0.45+0.04 −0.05 MJ |
2.73±0.06 | 1628+22 −21 |
0.059+0.062 −0.039 |
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