  | |
| Observation data Epoch 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−Vcolor index | 1.10[6] |
| J−Hcolor index | 0.556[6] |
| J−Kcolor index | 0.722[6] |
| Astrometry | |
| Radial velocity (Rv) | +6.92±0.12[2] km/s |
| Proper motion (μ) | RA: 110.617[2]mas/yr Dec.: −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) | ~2600AU[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 widebinary system between HD 11343 A, aK-type borderlinegiant star, and HD 11343 B, ared dwarf companion, located in the southern constellation ofEridanus about 500 light-years (150 pc) distant. Twogas giant exoplanets are known to orbit the primary star.
The HD 11343 system has anapparent magnitude of 7.88,[3] making it too faint to be visible by the naked eye fromEarth under most circumstances, but can be observed using binoculars[11] as an orangish dot nearAchernar.
The primary component, HD 11343 A, is ared-giant branch star slightly more massive than theSun (albeit one estimate places its mass at a significantly higher 2.0M☉[8]), but approximately eight times as large inradius and 25 times as luminous. It has aneffective temperature of 4,670 K (4,400 °C; 7,950 °F), corresponding to its spectral type of K2, and is slightlymetal-poor, with aniron content 71% that of the Sun.[9]
During a 2021 survey[12] searching for binaries within data fromGaia 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, asuper-Jupiter planet orbiting HD 11343 A was discovered fromradial-velocity observations, alongside three other substellar companions to giant stars, namelyHIP 74890 b,HIP 84056 b, andHIP 95124 b.[9] This planet, HD 11343 b, is estimated to be slightly larger thanJupiter and has a mass of 5.7MJ,[7] close to the initially estimated minimum of 5.5MJ.[9] It revolves around its host star at asemi-major axis of 2.8 AU (420,000,000 km), around where theasteroid belt would lie in theSolar System, every 1,585 days (4.34 years) in a mildlyeccentric 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 aminimum mass of 0.804MJ. 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, itsorbital 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 |
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