| Discovery[1] | |
|---|---|
| Discovery site | Kepler Space Observatory |
| Discovery date | 2016 |
| Transit | |
| Orbital characteristics | |
| 0.04994+0.00048 −0.00049 AU | |
| Eccentricity | 0.197+0.067 −0.060[2] |
| 4.01593 (± 0.0005)[3] d | |
| Inclination | 88.36 +0.17 −0.15[2] |
| Star | K2-38 |
| Physical characteristics | |
| 1.54±0.14[2] R🜨 | |
| Mass | 7.3+1.1 −1.0[2] ME |
Mean density | 11.0+5.8 −3.7 g cm−3 |
| 3.08+1.2 −0.74 g | |
| Temperature | 1,266 K (993 °C; 1,819 °F)[2] |
K2-38b, also designated EPIC 204221263 b, is a massive rocky exoplanet closely orbiting a Sun-like star and is one of the densest planets ever found. Discovered in 2016 by Crossfield et al. and later characterized by Sinukoff et al., K2-38b is a rocky super-Earth about 55% larger than Earth (nearly 20,000 km wide) but about 12 times more massive (around 7.2*10^25 kg, a bit less than Uranus) indicating a composition rich in iron and an extremely high surface gravity. The planet is within K2 Campaign 2, in the constellation Scorpius.
Characteristics
[edit]Mass, radius, and temperature
[edit]K2-38b is a massive rocky exoplanet significantly larger and more massive than Earth. It has a radius of 1.55 R🜨,[3] close to the 1.6 R🜨 limit where planets would begin to accumulate thick hydrogen-helium atmospheres and become something similar to a Mini-Neptune. However, K2-38b is instead a very dense terrestrial planet. Initially it was believed planet is made almost entirely of iron,[1] with a mass of about 12.0 ME and a density of about 17.5 g/cm3.[3] This made it one of the densest exoplanets ever discovered. Measurement in 2020 have resulted in lower mass of 7.3+1.1
−1.0[2] ME, and less extreme constraints on composition though.
Orbit
[edit]K2-38b has a very tight orbit around its host star. The planet takes just 4 days to complete a single orbit at a distance of about 0.05 AU. For comparison, Mercury orbits every 88 days at 0.38 AU from the Sun. The eccentricity of K2-38's orbit is slightly larger than that of Mars.[2]
Host star
[edit]The parent star K2-38 is a G2 main-sequence star, similar to our own Sun. It is 1.10 R☉ and 1.07 M☉, with a temperature of 5757 K and an unknown age. For comparison, the Sun has a temperature of 5778 K and is about 4.5 billion years old.[3]
The visual magnitude of K2-38, or how bright it appears to the human eye, is 11.39. Therefore, it is far too dim to be seen without a telescope.[1]
See also
[edit]References
[edit]- ^ a b c Sinukoff, Evan; et al. (2016). "Eleven Multiplanet Systems from K2 Campaigns 1 and 2 and the Masses of Two Hot Super-Earths". The Astrophysical Journal. 827 (1). 78. arXiv:1511.09213. Bibcode:2016ApJ...827...78S. doi:10.3847/0004-637X/827/1/78.
- ^ a b c d e f g Toledo-Padrón, B.; et al. (2020), "Characterization of the K2-38 planetary system", Astronomy & Astrophysics, 641: A92, arXiv:2007.01081, doi:10.1051/0004-6361/202038187, S2CID 220302044
- ^ a b c d "K2-38 b CONFIRMED PLANET OVERVIEW PAGE". NASA Exoplanet Archive. Retrieved 2018-01-20.
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction