| Observation dataEpoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Eridanus[1] |
| Right ascension | 01h 50m 06.33044s[2] |
| Declination | −54° 27′ 53.8624″[2] |
| Apparent magnitude (V) | 7.88[3] |
| Characteristics | |
| Evolutionary stage | Red giant branch[4] |
| Spectral type | K2III/IV[5] |
| B−V color index | 1.10[6] |
| J−H color index | 0.556[6] |
| J−K color index | 0.722[6] |
| Astrometry | |
| Radial velocity (Rv) | +6.92±0.12[2] km/s |
| Proper motion (μ) | RA: 110.617[2]mas/yrDec.: −46.798[2]mas/yr |
| Parallax (π) | 6.4964±0.0156 mas[2] |
| Distance | 502 ± 1 ly (153.9 ± 0.4 pc) |
| Absolute magnitude (MV) | +1.77[1] |
| Orbit | |
| Primary | HD 11343 A |
| Companion | HD 11343 B |
| Semi-major axis (a) | ~2600 AU[7] |
| Details | |
| HD 11343 A | |
| Mass | 1.17±0.28[7] / 2.009±0.115[8] M☉ |
| Radius | 7.83±1.02[9] R☉ |
| Luminosity | 25.1+5.8−5.6[9] L☉ |
| Surface gravity (log g) | 2.70±0.20[7] cgs |
| Temperature | 4,670±100[7] K |
| Metallicity[Fe/H] | −0.15±0.08[7] dex |
| Rotational velocity (v sin i) | 1.3±0.9[9] km/s |
| HD 11343 B | |
| Mass | 0.680+0.078−0.083[10] M☉ |
| Radius | 0.698+0.062−0.060[10] R☉ |
| Luminosity | 0.157[10] L☉ |
| Surface gravity (log g) | 4.58+0.11−0.09[10] cgs |
| Temperature | 4,351+142−113[10] K |
| Other designations | |
| CD−55 412, CPD−55 351, Gaia DR3 4912062772547406976, GC 2232, HD 11343, HIP 8541, SAO 232538, PPM 331373, TIC 231019255, TYC 8482-1124-1, GSC 08482-01124, 2MASS J01500631-5427539[6] | |
| Database references | |
| SIMBAD | data |
HD 11343 (HIP 8541) is a wide binary system between HD 11343 A, a K-type borderline giant star, and HD 11343 B, a red dwarf companion, located in the southern constellation of Eridanus about 500 light-years (150 pc) distant. Two gas giant exoplanets are known to orbit the primary star.
The HD 11343 system has an apparent magnitude of 7.88,[3] making it too faint to be visible by the naked eye from Earth under most circumstances, but can be observed using binoculars[11] as an orangish dot near Achernar.
The primary component, HD 11343 A, is a red-giant branch star slightly more massive than the Sun (albeit one estimate places its mass at a significantly higher 2.0 M☉[8]), but approximately eight times as large in radius and 25 times as luminous. It has an effective temperature of 4,670 K (4,400 °C; 7,950 °F), corresponding to its spectral type of K2, and is slightly metal-poor, with an iron content 71% that of the Sun.[9]
During a 2021 survey[12] searching for binaries within data from Gaia DR3, the star was found to be orbited by a 13th-magnitude[10] M-dwarf, designated HD 11343 B. It is about 70% as large as the Sun both in mass and radius, is slightly cooler than the primary red giant at 4,351 K (4,078 °C; 7,372 °F), and is situated at a separation of roughly 2,600 astronomical units (0.041 ly) from its brighter companion.[7][10]
In 2016, a super-Jupiter planet orbiting HD 11343 A was discovered from radial-velocity observations, alongside three other substellar companions to giant stars, namely HIP 74890 b, HIP 84056 b, and HIP 95124 b.[9] This planet, HD 11343 b, is estimated to be slightly larger than Jupiter and has a mass of 5.7 MJ,[7] close to the initially estimated minimum of 5.5 MJ.[9] It revolves around its host star at a semi-major axis of 2.8 AU (420,000,000 km), around where the asteroid belt would lie in the Solar System, every 1,585 days (4.34 years) in a mildly eccentric orbit.[9]
Another planet, HD 11343 c, was discovered in 2022 closer to HD 11343 A, also using the radial-velocity method. The planet is reportedly a Jupiter analog, larger than the previous planet but likely considerably less massive, with a minimum mass of 0.804 MJ. It orbits its star at a distance of 0.923 AU (138,100,000 km) every 228.5 days (0.626 years). Due to the faintness of the astrometric signals it produces, its orbital inclination cannot be well-constrained. The discovery paper for HD 11343 c notably presents a higher mass (7.71+0.73−1.19MJ), semi-major axis (3.729 AU), orbital period (5.07 years), and eccentricity (0.360) for HD 11343 b.[8]
| Companion(in order from star) | Mass | Semimajor axis(AU) | Orbital period(days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | ≥0.804 MJ | 0.923 +0.019−0.022 | 228.5 +3.3−3.8 | 0.169 +0.142−0.102 | — | ~1.24[13] RJ |
| b | 5.7 +1.2−1.1 MJ | 2.80 +0.21−0.25 | 1585 +27−40 | 0.122 +0.060−0.067 | 73.0 +12.0−16.0° | ~1.13[14] RJ |