| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sculptor |
| Right ascension | 01h 33m 17.14454s[1] |
| Declination | −38° 14′ 42.0572″[1] |
| Apparent magnitude (V) | 8.35[2] |
| Characteristics | |
| Spectral type | G1V[3] + ~M4[4] |
| Apparent magnitude (B) | 8.788[5] |
| Apparent magnitude (J) | 7.156[6] |
| Apparent magnitude (H) | 6.89[6] |
| Apparent magnitude (K) | 6.798[6] |
| B−V color index | 0.680±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | −3.94±0.13[1] km/s |
| Proper motion (μ) | RA: −31.339±0.013 mas/yr[1] Dec.: −38.258±0.015 mas/yr[1] |
| Parallax (π) | 17.8453 ± 0.0199 mas[1] |
| Distance | 182.8 ± 0.2 ly (56.04 ± 0.06 pc) |
| Absolute magnitude (MV) | 4.76[2] |
| Details[7] | |
| A | |
| Mass | 1.02+0.03 −0.02 M☉ |
| Radius | 1.11+0.05 −0.08[8] R☉ |
| Luminosity | 1.4[8] L☉ |
| Surface gravity (log g) | 4.42±0.05 cgs |
| Temperature | 5,798±50 K |
| Metallicity [Fe/H] | 0.08±0.04 dex |
| Rotational velocity (v sin i) | 2.36[9] km/s |
| Age | 5.56+0.65 −3.36 Gyr |
| B | |
| Mass | 0.21[4] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 9578 is a candidate wide binary star system located at a distance of approximately 183[1] light-years from the Sun in the southern constellation of Sculptor. The main star must be viewed with binoculars or a telescope, as its low apparent visual magnitude of 8.35[2] is too faint to be viewed with the naked eye. The system is drifting closer to the Sun with a radial velocity of −4 km/s.[1]
The primary component is an ordinary G-type main-sequence star with a stellar classification of G1V.[3] It is around five and a half billion years old,[7] and is spinning with a projected rotational velocity of 2.4 km/s.[9] The star has nearly the same mass as the Sun[7] but with an 11% greater girth.[8] It is radiating 1.4[8] times the luminosity of the Sun from its photosphere at an effective temperature of 5,798 K.[7]
A faint co-moving companion was detected in 2015, located at an angular separation of 3.245″±0.010″ along a position angle of 251.19°±0.10° from the primary, corresponding to a projected separation of 186 AU. Designated component B, it is a red dwarf with a class of around M4 and has an estimated 0.21 times the mass of the Sun.[4]
The discovery of a candidate extrasolar planetary companion was announced in a press release in October 2009,[11] but although mentioned in one paper,[4] it has not been published in a peer-reviewed journal, as noted by a 2017 study.[12] Designated HD 9578 b, this object is thought to have at least 0.62 times the mass of Jupiter, and take 1.35 years to orbit the primary, with an orbital semimajor axis of 1.27 AU.[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | ≥ 0.62 MJ | 1.27 | 494 | — | — | — |
Gaia DR3 was invoked but never defined (see the help page).Anderson2012 was invoked but never defined (see the help page).houk1979 was invoked but never defined (see the help page).Mugrauer2015 was invoked but never defined (see the help page).Høg2000 was invoked but never defined (see the help page).Cutri2003 was invoked but never defined (see the help page).AguileraGómez2018 was invoked but never defined (see the help page).Gaia DR2 was invoked but never defined (see the help page).Delgado_Mena2015 was invoked but never defined (see the help page).SIMBAD was invoked but never defined (see the help page).Udry2009 was invoked but never defined (see the help page).Ngo2017 was invoked but never defined (see the help page).