Exoplanets in Galaxy
In January 1992, two space objects changed our galaxy forever.
For the first time in history, evidence of planets or exoplanets orbiting other stars appeared outside the solar system: two rocky planets orbiting a star 2300 light-years away.
Now, 30 years later, the number of exoplanets has increased dramatically. On March 21, 2022, it was confirmed that 5,000 exoplanets had already been discovered. More specifically, the NASA catalog documents 5005 exoplanets, all with their own unique characteristics.
Each of these exoplanets appeared in a peer-reviewed study at the time of the month and was observed by many different methods of analysis and fixation.
The collection is a pretty good target for future research to explore these planets with new instruments, such as the recently launched James Webb Space Telescope and the upcoming Nancy Gray novel space telescope.
“This is not just a number. Each of them is a new planet, completely new. “Each of them is very exciting because we do not know anything about them yet,” said Jesse Christiansen, an astronomer at NASA’s Exoplanet Science Institute.
The first exoplanets in history were discovered by two astronomers, Alexander Wolshan and Dale Fryl – massive exoplanets 4.3 times and 3.9 times Earth, orbiting a dead star known as the millisecond pulsar; Stars of this type emit radio wave pulses at milliseconds.
A third, 0.2 Earth-mass exoplanet was discovered in 1994 around the star Leach. These exoplanets have been called poltergeist, phobeter, and drag.
The discovery indicated that the galaxy must have been crowded with such objects. Pulsars are one type of neutron star: the dead nuclei of massive stars that remain after the star is removed from outer space before death and collapses by its own gravity. The process of their formation is quite extreme and is often accompanied by colossal explosions.
“If you find planets around a neutron star, it means that the planets must be everywhere. “The process of planet formation must be quite stable,” Wolshan said.
However, there was one difficulty. The method used to identify the exoplanets was based on the synchrony of the star’s strong regular pulses, which changed very little of the gravitational influence of the bodies moving around.
Consequently, this method is only suitable for pulsars; Unsuitable for main sequence stars that do not have regular, millisecond pulses.
However, when NASA astronomer William Borough developed the transit method, the number of exoplanets has since really risen; The transit method involves observing faint, regular eclipses in starlight caused by the arrival of a planet between us and that star.
Launched in 2009, the Kepler Space Telescope has added more than 3,000 exoplanets to the list, with another 3,000 on the candidate list and awaiting confirmation.
In addition to the transit method, astronomers can study the gravitational effects of exoplanets on their own star. When objects move around a common center of gravity, the star “vibrates” slightly on the ground and its light waves change.
In addition, if you know the mass of a star, you can also study how much it oscillates and thus determine the mass of an exoplanet; And if you know the brightness of a star, you can also determine the size of an exoplanet.
This is how we know that there are so many planets in the universe that are so different from what we have in our solar system.
Hot Jupiters are huge gas giant planets that move very close to their own stars and therefore, their temperature is even higher than some stars.
The size of mini-Neptunes varies between the size of Earth and Neptune and may be life-threatening. There are also super-Earths that are rocky (solid) like our planet but have several times their mass.
Exoplanets are difficult to study directly because they are so small, faint, so far away, and often so close to bright stars that their light completely obscures what the exoplanet might reflect; Consequently, we still do not know much. There are still too many planets in the universe that our technologies are not yet able to detect.
However, in the coming years, advanced technologies and new methods of analysis will cross this line and we may find planets we could never have imagined. We may even find signs of life beyond the solar system.
Prepared according to ScienceAlert.