 Artist’s illustration of LHS 3844 b | |
| Discovery[1] | |
|---|---|
| Discovered by | Vanderspek et al. |
| Discovery date | September 2018 |
| Transit | |
| Designations | |
| Kua'kua,[2] TOI-136.01, TIC 410153553 b[3][4] | |
| Orbital characteristics | |
| 0.00622±0.00017 AU[3][4] | |
| 0.46292913±0.00000190 d[3][4] | |
| Inclination | 88.50±0.51[4] |
| Star | LHS 3844 |
| Physical characteristics | |
Mean radius | 1.303±0.022 R🜨[3][4] |
| Albedo | <0.2[5] |
| Temperature | 1,040 K (770 °C; 1,410 °F) (day side)[5] |
LHS 3844 b, formally named Kua'kua,[2] is an exoplanet orbiting the red dwarf LHS 3844, about 48.5 light-years (14.9 parsecs) away in the constellation Indus,[6] discovered using the Transiting Exoplanet Survey Satellite. It orbits its parent star once every 11 hours, and its radius is 1.32 times that of Earth.[1] It has a low albedo, indicating that its surface may resemble that of the Moon or Mercury. LHS 3844 b probably does not have an atmosphere as almost no heat goes to its night side, and it has a dayside temperature of 1,040 K (770 °C; 1,410 °F).[5][7] The presence of cloudy atmosphere with cloud tops above pressure level of 0.1 bar cannot be excluded though.[8]
In order to explain the lack of atmosphere, it has been proposed that the planet was formed interior to the star system's snow-line, because if it formed beyond the snow-line it would have carried volatiles, on the surface and in a thick atmosphere, that according to models on atmospheric loss should have been enough to sustain an atmosphere to the present.[9] The planet probably also formed with a volatile-poor outgassing mantle, in a stagnant lid regime, because if the mantle was similar in constitution to Earth's, with plate tectonics, then it should still have a thick atmosphere, unless the red dwarf consistently flared at an uncharacteristically extreme rate not yet considered in atmospheric loss models.[9] An alternative explanation for the lack of atmosphere could be through a large impact event, one with enough momentum to strip the planet of its atmosphere and a large portion of its mantle.[9] In order to explain the non replenishment of volatiles via comets back onto the planet, it is also proposed that perhaps there is an outer gas giant in the star system.[9]
