KELT-1 is a

F-type main-sequence star An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables ...

. Its surface temperature is 6518 K. It is similar to the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

in its concentration of heavy elements, with a

metallicity In astronomy, metallicity is the Abundance of the chemical elements, abundance of Chemical element, elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-Dark matter, dark) matt ...

Fe/H index of 0.008, but is much younger at an age of 1.75 billion years. The star is rotating very rapidly. A

red dwarf A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs are ...

stellar companion at a projected separation of 154 AU was detected in 2012, simultaneously with a planetary companion.

Planetary system

The star was found to be orbited by a low-mass

brown dwarf Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...

or giant planet in 2012. The atmosphere of the brown dwarf KELT-1b has been extensively measured from space- and ground-based observatories by a team of astronomers led by Thomas Beatty. They found that KELT-1b has an equilibrium temperature of 2422 K, but features a very strong contrast between measured dayside and nightside temperatures. Dayside temperature appears to be 3340 K, while nightside temperature is 1173 K. 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 the

subsolar point The subsolar point on a planet or a moon is the point at which its Sun is perceived to be directly overhead (at the zenith); that is, where the Sun's rays strike the planet exactly perpendicular to its surface. The subsolar point occurs at the ...

by 18.3°. KELT-1b's density of 22.1 g/cm³ is the highest among well characterized planets. The planetary orbit is well aligned with the equatorial plane of the star, with the misalignment angle equal to 2°. Despite the short orbital period, orbital decay of KELT-1b has not been detected as of 2018.

References

{{DEFAULTSORT:KELT-1 Andromeda (constellation) Binary stars Planetary systems with one confirmed planet Planetary transit variables F-type main-sequence stars J00012691+3923017 Brown dwarfs TIC objects

Planetary system

See also

References