Some planets have very high surface temperatures and rapid orbits. Hot Jupiters are planets in the size range of Jupiter and have similar compositions to Jupiter. Their size makes it easier to spot them using the transit method.
There is a planet that is very close to their stars and has very high surface temperatures. They are small, rocky, and they are in less than 24 hours. TESS found a planet that was only eight hours old.
The planet is almost as dense as iron.
The red dwarf star named GJ 361 is 31 light-years away. It is 70% as large as Earth and 45% as massive. Astronomers call it a sub- Earth.
The discovery is detailed in a paper. The title is a dense ultra- short period sub- Earth planet transiting a red dwarf star. The first author is a Post-Doctoral Researcher at the German Aerospace Center.
A principal research scientist at MIT said that they had found a Mars-sized planet that had the composition of Mercury. It is among the smallest planets detected to date, and it is spinning around an M dwarf.
Sub-Earths are so small that it can be hard to find them around other stars. Their small size makes their transit signals weak, and their low mass makes them barely tug on their host stars. The detection was easier because the star is a small M-dwarf.
Sub- Earths have no atmosphere because their stars strip it away. They don't have enough mass or a strong magnetic field to keep their atmospheres.
Why is the planet missing its atmosphere? How close was it to the door? Was this process peaceful or violent?
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TESS Team Member is Natalia Guerrero.
GJ 361b is the same.
It is showered with more radiation than Earth and there is no way the atmosphere can cope with that intensity. The surface temperature is around 1500 C. No living thing could survive the amount of energy stripped away from it.
It has no atmosphere and no chance of supporting life, but it is an interesting exoplanet because of its density.
Astronomers were able to measure some of the planet's other properties because it is so close to its star. The planet is rocky and likely has a core of solid iron and nickel, similar to Mercury, according to follow-up observations by the HARPS instrument at the La Silla Observatory. The planet's size and mass were determined by those observations.
The iron core makes up over 70% of the interior.
The structure of the exoplanet is similar to that of Mercury, according to the discoverers. The internal structure of Mercury is shown in this image. The surface is 100–300 km thick. The mantle is 600 km thick. The core is 1,800 km away. Credit: NASA
The situation of the exoplanet is very similar to that of our own Solar System. Its discovery raises a lot of questions.
TESS team member Natalia Guerrero said, "Understanding how these planets get so close to their host stars is a bit of a detective story." Why is the planet missing its atmosphere? How close was it to the door? Was the process peaceful or violent? Hopefully, this system will give us more information.
We know that planets can change positions. Jupiter did that. The theory of planet formation is called the nebular hypothesis. The leftover material from a star forms a disk that planets form from. There are limitations on where planets can form.
Planets can't be as close to their star as GJ . There is less material available for planetary formation that is close to the star, and the temperatures are too high for material to condense. There are planets that can't form there. The paper states that the surface temperature is high enough to cause the silicates and metallic iron to melt. They must form further out.
The density of GJ s is shown in relation to other rocky planets. The density is closer to pure iron than other planets, and it has an iron core that makes up most of the planet's radius. Flam et al 2021.
There are different types of planetary migration. When there is still a disk of gas around a young star, planetary migration takes place. The planets exert a influence on the gas as they move through it. That can cause an equal and opposite force on the planet. There can be either an inward or an outward migration.
Astronomers will likely study what happened in GJ s solar system.
There is a sign that says, "Look here for extra planets!"
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George Ricker is from MIT.
The star GJ 361 is a red dwarf. They host an average of 2.5 planets of less than four Earth radii, with the orbital periods less than 100 days, according to some estimates. Since M-dwarfs are low mass, it is easier to detect planets around them. The authors write that the transit signal produced by a planet around an M dwarf is larger than that of a planet around a solar-type star.
The principle of a similar principle holds true for radial velocity measurement. The authors say that the RV signal is larger for an M dwarf host than for a G dwarf. M dwarfs give an opportunity to search for exoplanets with small radii and low mass. The higher stellar activity of M dwarfs makes it difficult to accurately measure RV.
We have a good chance of seeing other planets in this system since this star is so close by. George Ricker is a senior research scientist in MIT's Kavli Institute for Astrophysics and Space Research.
M dwarfs can flare so powerfully that they may not support life on nearby planets. That flaring would make any planet that wasn't already too hot for life. Is it possible that the star host other planets further out?
Ricker said that the star's habitable zone would be around a month-long orbit.
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