It has been almost ten years since the launch of the mission.NASA "Kepler". Since 2009, this spacecraft has watched hundreds of thousands of stars in our own galaxy, measuring the total amount of light flux for each of them and looking for any, even minor changes. By the end of the mission, Kepler and its additional missions K2 discovered thousands of new planets near stars outside our system, including many potentially inhabited worlds the size of Earth.
If Kepler showed us that our galaxyfull of planets, his successor mission TESS - Transiting Survey Satellite - will show the transit worlds near the stars closest to us. If there is any Earthlike world passing in front of its native star relative to our line of sight, TESS will show it. For the first time we will be able to see the abundance of planets that are literally scattered under our noses.
TESS telescope set to work
The search for Kepler was an amazing adventure: he searched in a narrow field of view covering a distance of 3,000 light years. His main mission was to continuously view the same field of view for many years. Having caught a total of more than 100,000 stars, Kepler searched for systematic, periodic dips in the total amount of light coming from each star. If something was detected, it potentially indicated the presence of a planet with a magnitude and period of dips corresponding to the radius and orbital distance to the planet.
But TESS is different. Instead of studying a narrow strip of sky, TESS studies the sky entirely, sector by sector, in order to find planets near the stars closest to us. If a planet properly aligned with us is within about 200 light years away from a star, TESS will see it, determining the radius and distance to the orbit. Moreover, each TESS discovery that gives us a planet also gives us a system of candidates, looking at which future observatories - like the James Webb space telescope - can try to find signs of life.
TESS launched in April 2018, starting the searchnew worlds. His first scientific data collection began in July; After almost half a year, he released his first data set. During its life, TESS is expected to find thousands of new planets near thousands of stars, from gas giants the size of Jupiter to small solid worlds of Earth size.
When reviewing the first six segments, TESS found this:
- more than 300 candidate planets;
- 8 confirmed planets;
- including several giant planets;
- some of them are slightly larger than the Earth.
But the numbers do not make these discoveries something out of the ordinary. Only by examining them in detail can we appreciate the phenomenal science that TESS supplies us with.
Pi Mensae c
The first confirmed planet was Pi Mensae cwhich revolves around a star very similaron ours. Pi Mensae, by weight, is only 10% larger than our Sun and 20% larger in size. It is very similar to our star, but its system is very different. By blocking a small part of its light, Pi Mensae c is extremely close to its star, turning around it with a period of only 6.3 days. This is about twice the radius of the Earth and almost five times more massive, which implies a fairly typical situation for hot worlds the size of somewhere between the Earth and Neptune.
But this is not typical; it is significant. Back in 2001, a large planet was discovered that violates the orbit of Pi Mensae: Pi Mensae b. It was one of the most massive planets ever discovered: 10 times the mass of Jupiter. Its orbit is very eccentric, it leads it further than Jupiter from the Sun (5.54 AU), but leads closer than the Earth to the Sun (1.21 AU) in the periastron.
Now that Pi Mensae c has discovered TESS, wemet both a distant and a nearby planet in a system with such different properties and orbits. The leading theory is that planets nearby form in almost perfect circular orbits, but to create an eccentric planet with a mass of Jupiter (or more), something had to interfere with this process.
The Pi Mensae system is currentlythe most extreme known in this regard, and the mystery of how such systems come to such a configuration will surely be the subject of much research and discussion in the future.
The most extreme planet detected - LHS 3884bwhich is only slightly larger than Earth with a radius1.3 earthly. It is so close to the parent star that it makes a turn every 11 hours. Located at a distance of 49 light years from us, this world is so hot that its side facing the star can be filled with pools of melted lava in the hottest places. This world is so hot that, at least in theory, its breed itself is in a liquid state.
Although it is unlikely that a planet with suchproperties of mass and temperature has an atmosphere, it may still be present in a thin form on a permanent basis, depending on the chemical composition of the surface. The characteristics of such a system make it an ideal candidate for measuring the absorption spectrum of the atmosphere. If there is an atmosphere, we can find out what it consists of before telescopes are turned to it.
What is most impressive, TESS gave usneighboring star, behind which you need an eye and an eye: HD 21749. Located in some 53 light years, this star is smaller and less massive than the Sun: approximately 70% less. Being a K-class star, it should not bombard the planets near catastrophic flashes or block them tidal; if there was a world the size of the Earth at the right distance from this star, it would be a great chance for life to be born on it.
On the eve of the New Year academic team TESS has released a work announcing the discovery of the planet in the orbit of this star: HD 21749b, with a 36-day orbit and 2.84 Earth radius. This world, slightly smaller than Neptune, was confirmed by subsequent observations, which determined that its mass is 23.2 times the mass of the Earth, which makes it smaller, but more massive and denser than Uranus or Neptune.
This is interesting for a variety of reasons. First, at such distances the temperature should be warm, but not very hot: about 150 degrees Celsius. Secondly, it is the longest-period planet of all known within 100 light years from Earth. And perhaps the most interesting thing is that there is a hint of a signal - and a possible candidate planet - in the HD 21749 system. An additional candidate, if confirmed, will have a period of 8 days and a radius approximately equal to that of the earth.
If this planet exists, it will be the very first world of earthly dimensions, discovered by TESS: the smallest of those that this telescope has discovered.
TESS's ultimate goal is to find Earth-likeworlds and star systems in which solid, potentially habitable worlds can be. Since TESS is optimized for finding the nearest stars to us, its greatest finds will be among the first targets for future, the most powerful observatories that can not only find these worlds, but also measure their atmospheric contents. If we are lucky, some of these worlds will contain water, methane, carbon dioxide, or even oxygen in atmospheres.
Nobody says that these worlds will definitely beinhabited, but TESS will bring us one step closer to finding the nearest worlds, which may be the greatest hope of humanity for finding life outside our solar system. Those worlds that we have found so far are absolutely adorable. TESS is already beginning to meet the highest expectations, even a few months after launch.
Just imagine if we can find a second Earth within some 200 light years from us. Will we plan a mission? Tell in our chat in Telegram.