HD 16754 is a binary[11] or triple-star[8] system in the constellation Eridanus. It has the Bayer designation s Eridani; HD 16754 is the designation from the Henry Draper catalogue. The system is visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.74.[2] It is located at a distance of approximately 132 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +18 km/s.[2] The system is a member of the Columba association of co-moving stars.[12]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Eridanus |
Right ascension | 02h 39m 47.96544s[1] |
Declination | −42° 53′ 30.3638″[1] |
Apparent magnitude (V) | +4.74[2] |
Characteristics | |
Spectral type | A1 Vb[3] + M2-5V[4] + ? |
B−V color index | 0.061±0.003[2] |
Astrometry | |
Radial velocity (Rv) | +18.0±4.2[2] km/s |
Proper motion (μ) | RA: +88.20[5] mas/yr Dec.: −17.82[5] mas/yr |
Parallax (π) | 24.7076 ± 0.3930 mas[1] |
Distance | 132 ± 2 ly (40.5 ± 0.6 pc) |
Absolute magnitude (MV) | +1.76[6] |
Details | |
Aa | |
Mass | 1.95[7] M☉ |
Radius | 1.93[8] R☉ |
Luminosity | 17.44[2] L☉ |
Surface gravity (log g) | 4.40±0.14[7] cgs |
Temperature | 9,099±309[7] K |
Metallicity [Fe/H] | −0.06[3] dex |
Rotational velocity (v sin i) | 167.6±1.7[9] or 13.4±1.5[6] km/s |
Age | 212[7] or 30[8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
This object was flagged as an astrometric binary based on proper motion measurements made from the Hipparcos spacecraft.[13][14] Zuckerman et al. (2011) consider it a multi-star system, with a bright A-type primary plus a faint M-type companion at an angular separation of 25″ to the north. The astrometric companion to the primary remains unresolved.[8]
The main component is an A-type main-sequence star with a stellar classification of A1 Vb.[3] Based upon stellar models, it has an age estimated at 212 million years.[7] Consistency with its membership in the Columba association suggests a much younger age of 30 million years.[8] Earlier measurements showed a high projected rotational velocity of 168 km/s.[9] However, Ammler-von Eiff and Reiners (2012) found a much lower velocity of 13 km/s.[6]
The visible companion is a red dwarf star with a class in the range M2-5V. The system is a source of X-ray emission with a luminosity of 924×1020 W, which is most likely coming from this component and the unresolved companion.[4]