LTT 1445
Hubble ACS/HRC image showing all three stars. Upper left is LTT 1445 A and in the lower right part of the image is the LTT 1445 BC pair. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Eridanus |
| LTT 1445 A | |
| Right ascension | 03h 01m 51.39367s |
| Declination | −16° 35′ 36.0312″ |
| Apparent magnitude (V) | 11.22±0.02 |
| LTT 1445 BC | |
| Right ascension | 03h 01m 51.04s |
| Declination | −16° 35′ 31.1″ |
| Apparent magnitude (V) | 11.37±0.03 |
| Characteristics | |
| Spectral type | M2.5+M3.0+M |
| Variable type | flare star (A & C) |
| Astrometry | |
| LTT 1445 A | |
| Radial velocity (Rv) | −5.74±0.33 km/s |
| Proper motion (μ) | RA: −369.972 mas/yr Dec.: −267.931 mas/yr |
| Parallax (π) | 145.6922±0.0244 mas |
| Distance | 22.387 ± 0.004 ly (6.864 ± 0.001 pc) |
| Orbit | |
| Primary | LTT 1445 B |
| Companion | LTT 1445 C |
| Period (P) | 36.2±5.3 yr |
| Semi-major axis (a) | 1.159±0.076″ |
| Eccentricity (e) | 0.50±0.11 |
| Inclination (i) | 89.64±0.13° |
| Longitude of the node (Ω) | 137.63±0.19° |
| Periastron epoch (T) | 2019.2±1.7 |
| Argument of periastron (ω) (secondary) | 209±13° |
| Details | |
| A | |
| Mass | 0.257±0.014 M☉ M☉ |
| Radius | 0.271+0.019 −0.010 R☉ R☉ |
| Luminosity (bolometric) | 0.00805±0.00035 L☉ |
| Surface gravity (log g) | 4.967+0.061 −0.075 cgs |
| Temperature | 3,337±150 K |
| Metallicity [Fe/H] | −0.34±0.08 dex |
| B | |
| Mass | 0.215±0.014 M☉ |
| Radius | 0.236±0.027 R☉ |
| C | |
| Mass | 0.161±0.014 M☉ |
| Radius | 0.197±0.027 R☉ |
| Rotation | 1.4 d |
| Other designations | |
| BD−17 588, HIP 14101, WDS J03019-1633A,BC, IRAS 02595-1647, 2MASS J03015142-1635356, 2MASS J03015107-1635306, TIC 98796344, TOI-455, GJ 3192, GJ 3193 | |
| Database references | |
| SIMBAD | The system |
| A | |
| BC | |
| Exoplanet Archive | data |
LTT 1445 is a triple M-dwarf system 22.4 light-years (6.9 parsecs) distant in the constellation Eridanus. The primary LTT 1445 A hosts two exoplanets—one discovered in 2019 that transits the star every 5.36 days, and another found in 2021 that transits the star every 3.12 days, close to a 12:7 resonance. As of October 2022 it is the second closest transiting exoplanet system discovered, with the closest being HD 219134 bc.