  | |
| Observation data EpochJ2000 EquinoxJ2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 19m 46.38309s[1] |
| Declination | −11° 58′ 29.4577″[1] |
| Apparent magnitude (V) | 4.770[2] + 12.4[3] |
| Characteristics | |
| Evolutionary stage | red clump[4] |
| Spectral type | G7III[5] or G8II[6] |
| U−Bcolor index | +0.67[7] |
| B−Vcolor index | +0.927±0.017[8] |
| Astrometry | |
| Radial velocity (Rv) | −1.18±0.09[9] km/s |
| Proper motion (μ) | RA: −29.269[1]mas/yr Dec.: +11.613[1]mas/yr |
| Parallax (π) | 9.7770±0.1610 mas[1] |
| Distance | 334 ± 5 ly (102 ± 2 pc) |
| Absolute magnitude (MV) | −0.29[8] |
| Details | |
| 26 Hya A | |
| Mass | 2.72[10] M☉ |
| Radius | 15.14+0.81 −2.47[1] R☉ |
| Luminosity | 138.5±2.7[1] L☉ |
| Surface gravity (log g) | 2.48±0.07[11] cgs |
| Temperature | 5,003±82[10] K |
| Metallicity[Fe/H] | −0.13±0.06[11] dex |
| Rotational velocity (v sin i) | 2.7[9] km/s |
| Age | 0.51[10] Gyr |
| Other designations | |
| 26 Hya,BD−11°2609,FK5 2741,HD 80499,HIP 45751,HR 3706,SAO 155096,WDS J09198-1158AB[12] | |
| Database references | |
| SIMBAD | data |
26 Hydrae is abinary star[3] system located 334 light years away from the Sun in theequatorialconstellation ofHydra. It is visible to the naked eye as a faint, yellow-hued point of light with a combinedapparent visual magnitude of 4.77,[2] just a few degrees away fromAlphard. The system is moving closer to the Earth with a leisurelyradial velocity of -1 km/s.[9]
Keenan and McNeil (1989) gave the brighter component astellar classification of G7 III,[5] matching an aginggiant star. Houk and Swift (1999) have it classed as a G8II[6]bright giant. This is ared clump giant,[4] which indicates it is on thehorizontal branch and is generating energy throughhelium fusion at itscore. It has a high lithium abundance and displays afar infraredemission excess.[13] The star is an estimated 510[10] million years old with 2.72[10] times themass of the Sun and has expanded to 15[1] times theSun's radius. It is radiating 139[1] times theluminosity of the Sun from its swollenphotosphere at aneffective temperature of 5,003 K.[10]
The secondary component is a magnitude 12.4 star at anangular separation of3.2″, as of 2008.[3]
