HD 16754
HD 16754 is a binary or triple-star 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. It is located at a distance of approximately 132 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +18 km/s. The system is a member of the Columba association of co-moving stars.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 02h 39m 47.96544s |
| Declination | −42° 53′ 30.3638″ |
| Apparent magnitude (V) | +4.74 |
| Characteristics | |
| Spectral type | A1 Vb + M2-5V + ? |
| B−V color index | 0.061±0.003 |
| Astrometry | |
| Radial velocity (Rv) | +18.0±4.2 km/s |
| Proper motion (μ) | RA: +88.20 mas/yr Dec.: −17.82 mas/yr |
| Parallax (π) | 24.7076 ± 0.3930 mas |
| Distance | 132 ± 2 ly (40.5 ± 0.6 pc) |
| Absolute magnitude (MV) | +1.76 |
| Details | |
| Aa | |
| Mass | 1.95 M☉ |
| Radius | 1.93 R☉ |
| Luminosity | 17.44 L☉ |
| Surface gravity (log g) | 4.40±0.14 cgs |
| Temperature | 9,099±309 K |
| Metallicity [Fe/H] | −0.06 dex |
| Rotational velocity (v sin i) | 167.6±1.7 or 13.4±1.5 km/s |
| Age | 212 or 30 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. 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.
The main component is an A-type main-sequence star with a stellar classification of A1 Vb. Based upon stellar models, it has an age estimated at 212 million years. Consistency with its membership in the Columba association suggests a much younger age of 30 million years. Earlier measurements showed a high projected rotational velocity of 168 km/s. However, Ammler-von Eiff and Reiners (2012) found a much lower velocity of 13 km/s.
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.