| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda[1] |
| Right ascension | 00h 01m 26.9168s[2] |
| Declination | +39° 23′ 01.784″[2] |
| Apparent magnitude (V) | 10.63[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F5[4] |
| Astrometry | |
| Radial velocity (Rv) | 1.296[2] km/s |
| Proper motion (μ) | RA: −9.696[2]mas/yr Dec.: −7.823[2]mas/yr |
| Parallax (π) | 3.6836±0.0144 mas[2] |
| Distance | 885 ± 3 ly (271 ± 1 pc) |
| Position (relative to KELT-1)[5] | |
| Component | KELT-1B |
| Epoch of observation | 2012 |
| Angular distance | 0.588±0.001″ |
| Position angle | 157.4±0.2° |
| Projected separation | 154±8AU |
| Details[5] | |
| Mass | 1.324±0.026 M☉ |
| Radius | 1.462+0.037 −0.024 R☉ |
| Luminosity | 3.11±0.05[6] L☉ |
| Surface gravity (log g) | 4.229+0.012 −0.019 cgs |
| Temperature | 6,518±50 K |
| Metallicity[Fe/H] | 0.008±0.073 dex |
| Rotational velocity (v sin i) | 55 km/s |
| Age | 1.75±0.25 Gyr |
| Other designations | |
| TOI-1476,TYC 2785-2130-1,GSC 02785-02130,2MASS J00012691+3923017[7] | |
| Database references | |
| SIMBAD | data |
KELT-1 is aF-type main-sequence star. Its surface temperature is 6518±50K. It is similar to theSun in its concentration of heavy elements, with ametallicity Fe/H index of 0.008±0.073, but is much younger at an age of 1.75±0.25 billion years. The star is rotating very rapidly.[5]
Ared dwarf stellar companion at a projected separation of 154±8 AU was detected in 2012, simultaneously with a planetary companion.[5]
The star was found to be orbited by a low-massbrown dwarf or giant planet in 2012.[5]
The atmosphere of the brown dwarfKELT-1b has been extensively measured from space- and ground-based observatories by a team of astronomers led byThomas Beatty. They found that KELT-1b has an equilibrium temperature of 2422+32
−26K,[5] but features a very strong contrast between measured dayside and nightside temperatures. Dayside temperature appears to be 3340±110K,[8] while nightside temperature is 1173+175
−130K.[9] The excess dayside temperature may be an artifact arising from highly reflective (dayside albedo reaching 0.5, which is unusual for hot planets and brown dwarfs) rock-vapor clouds. Also, the brightest band is shifted eastward from thesubsolar point by 18.3±7.4°.[8]
KELT-1b's density of 22.1+5.62
−9.16 g/cm3 is the highest among well characterized planets.[6]
The planetary orbit is well aligned with the equatorial plane of the star, with the misalignment angle equal to 2±16°.[5] Despite the short orbital period, orbital decay of KELT-1b has not been detected as of 2018.[10]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 27.23+0.50 −0.48 MJ | 0.02466±0.00016 | 1.21749397 | 0 | 85.3+2.9 −2.6° | 1.15+0.10 −0.15 RJ |
