2024-02-05 09:40:45
Astronomers have found a super-Earth planet orbiting a red dwarf Saturn at a distance of 137 light years from us The radius of the planet, whose catalog name is TOI-715b, is 1.55 times the radius of the Earth – and it is located inthe sitting area“, that is, at the right distance from its star to allow the existence of liquid water on the surface. In the red dwarf system there is another candidate for a planet, also in the sitting area of the system – but at the radius of the Earth. If it turns out that it is indeed a planet, it will be a planet The smallest that the TESS space telescope has discovered inside the satyr region.
A world that shouldn’t exist
TESS space telescopeshort for Transiting Exoplanet Survey Satellite, discovered thousands Extrasolar planets Since it was launched in 2018. From there, the telescope looks for objects that pass between the telescope and the stars and thus dim the starlight, with a maximum sensitivity of up to 0.1% dimming of the starlight.
Like most stars in our universe, TOI-715b is a red dwarf – a small, faint star much brighter than the Sun. It is an average red dwarf – about a quarter of the mass and radius of the Sun. As such, its equatorial region is much closer than that of our Sun, and one year on TOI-716b lasts only 19 days.
Of course, the correct distance from the star does not guarantee suitable conditions for life as we know it – there are many variables such as the degree of light reflectivity (albedo) of the planet, its mass and the composition of the atmosphere. fact thatMars The frozen andVenus The hot are both on the edge of the sitting area of Solar System – and water certainly cannot exist today on their surface in a liquid state of accumulation. That’s why astronomers sometimes prefer a more conservative definition of the emissive zone, according to which a rocky world receives between 42% and 84% of the solar radiation that Earth receives. TOI-716b is right in the center of this “conservative sitting area”.
Equally intriguing is the fact that the world TOI-716b is not supposed to exist. Since humanity started finding extrasolar planets, it has become clear that there are two very common types of worlds – that simply do not exist in our solar system: super-Earths and mini-Neptunes. But while hundreds of super-Earth and mini-Neptune planets have been found, it is very rare to find planets in between – between a radius of 1.5 times and a radius of 2 times that of Earth.
Scientists believe that our universe does not tend to “produce” worlds with a radius of between 1.5 and 2 times the Earth, and that the few of these worlds that were found began their journey as mini-Neptunes with a radius of over 2 Earth, and later lost part of their mass in the process of evaporating in the light – That is, due to powerful electromagnetic radiation from the star, which blew part of their atmosphere into space. At a radius of 1.55 times Earth, TOI-716b may shed light on this mysterious process of shrinking mini-Neptunes, and confirm (or disprove) the theory.
Shortly after TOI-716b’s orbit, a smaller object appears to dim the red dwarf’s light. If further observations confirm that it is a planet, it seems that before us is a planet with a radius equal to the radius of the Earth. It is at the far end of the conservative accretionary region and completes orbit around its star every 25 days. As mentioned, if the candidate is officially recognized as a planet, it will be the smallest planet that the TESS space telescope has found within the sat region.
But is one of the two planets of the TOI-716 system inhabited? For that we will have to wait forSpace Telescope James WB. TESS knows how to measure the size, mass, material density and orbit of extrasolar planets, but its main function is to prepare the area for Webb’s observations, which is able to directly photograph the atmospheres of some of the nearby planets found by TESS – and analyze their composition according to the light absorption lines in the material. Being relatively close and dense (so the planets pass very close to Saturn), the TOI-716 system is a perfect candidate for Webb’s capabilities, and the astronomers who discovered the planets are eagerly awaiting their “donor” on the telescope.
The two candidates Wob discovered around two white dwarfs. The star in the middle is formed when Webb’s coronagraph blocks the light of the Saturn star to emphasize the dim light of the planet around it. Credit: Mulaney, et al, 2024
Webb peeks into the future
Meanwhile, Webb himself is very busy, and continues to amaze us with his discoveries. The space telescope recently found two candidates for planets orbiting two different “dead” stars, or white dwarfs. A white dwarf is the core of a M starThe main serieslike our sun, which remains after the star runs out of “fuel”, i.e. hydrogen, it swells into a red giant and sheds most of its mass asplanetary nebula. In five billion years (more or less), our sun You will swell into a red dwarf, and its wings will swallow you Mercury, Venus, the Earth and maybe even Mars. The outer layers will cool, and all that will be left in the solar system is a small, dense, cold white dwarf and its surroundings Jupiter, Saturn, Uranus andNeptune cold and dark.
Although they are very rare, this is not the first time astronomers have found worlds orbiting dead stars. What makes Webb’s discovery so interesting is that the white dwarfs WD 1202-232 and WD 2105-82 are very similar to the white dwarf that our Sun is expected to leave behind – and the planets that orbit them are similar in mass and orbit to Jupiter and Saturn. In other words, Webb provides us with a glimpse into the future of the Solar System, proving that Jupiter and Saturn will indeed survive the death of the Sun.
It should be noted that the Webb Space Telescope photographed these planets directly, meaning it photographed the light of the planets themselves. Since the 1990s, astronomers have discovered about 5,000 extrasolar planets, of which only 50 have been photographed directly – and not as shadows on the background of their stars.
#planets #light #years #Earths #twin