HD 17925 is a variable star in the equatorial constellation of Eridanus. It has the Gould designation 32 G. Eridani and the variable star designation EP Eri. The star has a yellow-orange hue and is dimly visible to the naked eye in good seeing conditions with an apparent visual magnitude that varies from 6.03 down to 6.08.[16] It is located nearby at a distance of 34 light years from the Sun based on parallax,[2] and is drifting further away with a radial velocity of +18 km/s.[7] It is a likely member of the Local Association of nearby, co-moving stars.[12] The spectrum shows a strong abundance of lithium, indicating that it is young star.[17] This likely makes its point of origin the nearby Scorpio–Centaurus Complex.[18]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Eridanus |
Right ascension | 02h 52m 32.12819s[2] |
Declination | –12° 46′ 10.9681″[2] |
Apparent magnitude (V) | 6.04[3] |
Characteristics | |
Evolutionary stage | Main sequence |
Spectral type | K1V[4] |
U−B color index | +1.41[5] |
B−V color index | +0.86[5] |
Variable type | RS CVn[6] |
Astrometry | |
Radial velocity (Rv) | +17.77±0.08[7] km/s |
Proper motion (μ) | RA: 397.353[2] mas/yr Dec.: −189.281[2] mas/yr |
Parallax (π) | 96.5200 ± 0.0258 mas[2] |
Distance | 33.792 ± 0.009 ly (10.361 ± 0.003 pc) |
Absolute magnitude (MV) | 5.97[8] |
Details | |
Mass | 0.88[9] M☉ |
Radius | 0.85±0.05[10] R☉ |
Luminosity | 0.408±0.005[2] L☉ |
Surface gravity (log g) | 4.58[9] cgs |
Temperature | 5,225±5[11] K |
Metallicity [Fe/H] | +0.10[12] dex |
Rotation | 6.6 days[12] |
Rotational velocity (v sin i) | 4.80[13] km/s |
Age | 100[14] Myr |
Other designations | |
Database references | |
SIMBAD | data |
The stellar classification of HD 17925 is K1V,[4] which indicates this is a K-type main-sequence star that is engaged in core hydrogen fusion. It is an active star[17] that is classified as a RS Canum Venaticorum variable,[16] showing a rotational modulation with a period of 6.9 days, and has been observed to flare.[6] The star has an estimated age of 100[14] million years and is spinning with a projected rotational velocity of 4.8 km/s.[13] The rotation period of 6.6 days days can be determined from its activity cycle.[12] The star has 88%[9] of the mass of the Sun and 85%[10] of the Sun's radius. It is radiating 41%[2] of the luminosity of the Sun from its photosphere at an effective temperature of 5,225 K.[11]
The presence of an unseen companion has been suggested based on variations in the widths of absorption lines in the star's photosphere.[17] It displays low-amplitude radial velocity variation, which may indicate it is a spectroscopic binary.[10] However, the binary hypothesis doesn't appear to be consistent with Hipparcos satellite data.[12] An infrared excess has been detected around this star, most likely indicating the presence of a circumstellar disk at a radius of 17.9 AU. The temperature of this dust is 52 K.[19]