 HD 984 is the brightest star in this Sloan Digital Sky Survey image. The spiral galaxy NGC 47 can be seen at upper left. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus[note 1] |
| Right ascension | 00h 14m 10.25283s[1] |
| Declination | −07° 11′ 56.8127″[1] |
| Apparent magnitude (V) | 7.32[2] |
| Characteristics | |
| A | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | F7V[3] |
| B−V color index | 0.522±0.01[4] |
| B | |
| Evolutionary stage | Brown dwarf[4][5] |
| Spectral type | M6.5±1.5[6] |
| Apparent magnitude (J) | 13.28±0.06[6] |
| Apparent magnitude (H) | 12.6±0.05[6] |
| Astrometry | |
| Radial velocity (Rv) | 1.04±0.25[1] km/s |
| Proper motion (μ) | RA: 104.775 mas/yr[1] Dec.: −68.016 mas/yr[1] |
| Parallax (π) | 21.877 ± 0.0249 mas[1] |
| Distance | 149.1 ± 0.2 ly (45.71 ± 0.05 pc)[1] |
| Absolute magnitude (MV) | 3.95±0.07[4] |
| Orbit[5] | |
| Primary | A |
| Companion | B |
| Period (P) | 140+50 −30 yr |
| Semi-major axis (a) | 28+7 −4 AU |
| Eccentricity (e) | 0.76±0.05 |
| Inclination (i) | 120.8+1.8 −1.6° |
| Details | |
| A | |
| Mass | 1.2±0.06[4] M☉ |
| Radius | 1.247±0.053[4] R☉ |
| Luminosity | 2.218+0.142 −0.134[6] L☉ |
| Surface gravity (log g) | 4.38±0.06[3] cgs |
| Temperature | 6326±80[3] K |
| Metallicity [Fe/H] | −0.01±0.12[3] dex |
| Rotation | 1.39±0.05[7] d |
| Rotational velocity (v sin i) | 42.13±1.65[4] km/s |
| Age | 30–200[4] Myr |
| B | |
| Mass | 61±4[5] MJup |
| Radius | 0.162[5][a] R☉ |
| Luminosity | 1.318+0.094 −0.088×10−3[5] L☉ |
| Temperature | 2730+120 −180[6] K |
| Metallicity [Fe/H] | −0.62±0.02[3][note 2] dex |
| Rotational velocity (v sin i) | 12.72+0.03 −0.02[3] km/s |
| Position (relative to A)[4] | |
| Component | B |
| Epoch of observation | 2015 |
| Angular distance | 201.6±0.4 mas |
| Position angle | 92.2±0.5° |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 984 is a F-type main-sequence star located in the equatorial constellation Cetus. It is a young star, estimated 30 to 200 million years old, and is orbited by a brown dwarf companion. Parallax measurements by the Gaia spacecraft imply a distance of 150 light-years (46 pc) to HD 984. At an apparent magnitude of 7.32, the star is too dim to be visible to the naked eye.
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