HD 4113
Binary star system in the constellation of Sculptor
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HD 4113 is a double star system in the southern constellation of Sculptor. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.88.[3] The distance to this star, as estimated by parallax measurements, is 137 light years.[2] It is receding away from the Sun with a radial velocity of +5 km/s.[2]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sculptor[1] |
| HD 4113 A | |
| Right ascension | 00h 43m 12.59559s[2] |
| Declination | −37° 58′ 57.4777″[2] |
| Apparent magnitude (V) | 7.880±0.013[3] |
| HD 4113 B | |
| Right ascension | 00h 43m 11.89423s[4] |
| Declination | −37° 58′ 09.1687″[4] |
| Apparent magnitude (V) | 12.70±0.02[3] |
| Characteristics | |
| Spectral type | G5V and M0–1V[3] |
| B−V color index | 0.716±0.003[3] |
| Astrometry | |
| HD 4113 A | |
| Radial velocity (Rv) | 5.05±0.12[2] km/s |
| Proper motion (μ) | RA: 49.412±0.016 mas/yr[2] Dec.: −114.290±0.024 mas/yr[2] |
| Parallax (π) | 23.8256±0.0240 mas[2] |
| Distance | 136.9 ± 0.1 ly (41.97 ± 0.04 pc) |
| Absolute magnitude (MV) | 4.780±0.046[3] |
| HD 4113 B | |
| Radial velocity (Rv) | 4.44±0.39[4] km/s |
| Proper motion (μ) | RA: 53.733±0.022 mas/yr[4] Dec.: −113.983±0.032 mas/yr[4] |
| Parallax (π) | 23.9023±0.0327 mas[4] |
| Distance | 136.5 ± 0.2 ly (41.84 ± 0.06 pc) |
| Absolute magnitude (MV) | 9.600±0.049[3] |
| Orbit[5] | |
| Name | HD 4113 C |
| Period (P) | 348.325+21.932 −15.139 yr |
| Semi-major axis (a) | 50.438+2.060 −1.420 AU |
| Eccentricity (e) | 0.648+0.008 −0.007 |
| Inclination (i) | 83.456+2.342 −1.269° |
| Longitude of the node (Ω) | 225.686+0.704 −1.486° |
| Periastron epoch (T) | 2324305.035+127045.323 −7894.349 |
| Argument of periastron (ω) (secondary) | 249.665+3.552 −4.805° |
| Semi-amplitude (K1) (primary) | 0.263535+0.002058 −0.003037 km/s |
| Details[6] | |
| A | |
| Mass | 1.02+0.02 −0.03 M☉ |
| Radius | 1.08+0.02 −0.04[7] R☉ |
| Luminosity | 1.085+0.04 −0.03[7] L☉ |
| Surface gravity (log g) | 4.31±0.04 cgs |
| Temperature | 5,638±50 K |
| Metallicity [Fe/H] | 0.20±0.04 dex |
| Rotational velocity (v sin i) | 2.324[3] km/s |
| Age | 7.29+1.91 −1.46 or 5.0+1.3 −1.7[3] Gyr |
| B | |
| Mass | 0.55[3] M☉ |
| Surface gravity (log g) | 4.76[3] cgs |
| Temperature | 3,833[3] K |
| C | |
| Mass | 51.913+0.604 −0.458[5] MJup |
| Radius | 1.4–1.5[3] RJup |
| Surface gravity (log g) | 4.5–5[3] cgs |
| Temperature | 500–600[3] K |
| Other designations | |
| CD−38°223, GC 858, HD 4113, HIP 3391, SAO 192693, GSC 03654-02131[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
System components
The primary member of this system, component A, is a Sun-like G-type main-sequence star with a stellar classification of G5V.[3] Estimates of its age are five[3] to seven[6] billion years old, and it is spinning with a leisurely projected rotational velocity of 2.3 km/s.[3] The star is metal rich, with nearly the same mass,[6] radius, and luminosity[7] as the Sun.
Orbiting this star is a giant planet and a brown dwarf (HD 4113 C); the latter has been directly imaged. It also has a co-moving stellar companion, designated component B, which is a red dwarf with a class of M0–1V at an angular separation of 43″. This angle is equivalent to a projected separation of 2,000 AU.[3]
The most recent parameters for HD 4113 C as of 2022 come from a combination of data from radial velocity, astrometry, and imaging, showing that it is about 52 times the mass of Jupiter, and on an eccentric orbit with a semi-major axis of about 50.4 AU and an orbital period of about 348 years.[5]
Observations with SPHERE found a lack of a detection of HD 4113 C in H3, likely due to methane absorption in the H-band. Using the extracted spectrum the team estimated a spectral type of T9.[3] Observation with GRAVITY+ showed strong methane absorption in the K-band spectrum of HD 4113 C. The inconsistency between temperature and isochronal mass estimate is seen as potential evidence for a binary brown dwarf.[9]
Planetary system
On 26 October 2007, Tamuz et al. used the radial velocity method to find a planet with a minimum mass one and half times that of Jupiter orbiting at 1.28 AU away from HD 4113 A. The planet's orbit is highly eccentric.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.703+0.040 −0.059 MJ |
1.280±0.004 | 1.442+0.0002 −0.0001 |
0.899+0.004 −0.003 |
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