hot jupiter

[Kozima]

Hot Jupiter, as the name suggests, means hot Jupiter, but isn't it actually a scorching gas planet? Hot Jupiters are probably the most easily discovered, but because of their small numbers, they are rarely discovered. Hot Jupiter was the first exoplanet to be discovered. I will explain why. Hot Jupiters are very close to their stars and very massive. This makes it easy to observe with the Doppler method, which has been used since the early days of exoplanet exploration (except for the astrometry method, which is difficult to discover from the ground even today). However, in the early days, observations were often miscalculated, and all the discoveries of extrasolar planets were dismissed. Therefore, it was recommended to reduce the survey cost and personnel. But in 1992. It was the first exoplanet discovered. The name is the planet PSR B1257+12b. The discovery method is the pulsar timing method.

Pulsars rotate so precisely that they are said to be the beacons of the universe, and they emit jets. Furthermore, although it maintains a strong magnetic field, if a planet exists, the gravity of the planet will shift the rotation period. What is necessary is to observe the period of the deviation of the rotation period. Although it is an extremely accurate exoplanet discovery method, the number of pulsars is small and the probability of planet formation is also low. In the first place, a pulsar is a celestial body that has become very small due to the gravitational collapse of the iron core caused by a supernova explosion of a star with a mass 10 to 29 times that of the sun. But scientists weren't looking for pulsar planets. They wanted a planet orbiting a normal main-sequence star. After that, Dr. Mayor, who was observing the 51st star Pegasi. Scientists at the time were unaware of the existence of hot Jupiters, as they thought gas planets orbited with long orbital periods. In addition, there were exoplanets that had been discovered but had not been confirmed due to the influence of technology. The mass of 51 Pegasi is 0.5 times that of Jupiter. The orbital period is 4.25 days. It's 102 hours in time. It's surprisingly shorter than most people think. The exoplanet with the shortest orbital period is GJ 367b (Gliese 367b). The orbital period is 7.7 hours. A lot of hot Jupiters were discovered after that, but it is true that there are few hot Jupiters after all. Hot Jupiters are so close to their stars that they are likely to be absorbed by their host stars. If it reaches the red giant stage, it will surely be swallowed up. Moreover, it will be swallowed in the early stage. Anyway, the chances of life on Hot Jupiter are close to 0%.