00:00A new super-Earth has recently been observed by astronomers, and it arouses great interest.
00:06This planet, designated as TOA-715b, has an equivalent size to one and a half times that of our Earth,
00:14which justifies its name of super-Earth.
00:17In addition, it is relatively close to us, at only 137 light years.
00:22To put this into perspective, the majority of exoplanets are located at several hundred light years,
00:28while fascinating celestial objects such as black holes and nebulae are generally thousands of light years away from us.
00:35Could it therefore be habitable?
00:37The habitable zone represents an estimate of the regions where a planet could present favorable conditions to the existence of liquid water.
00:45This refers to a specific distance from the star, where the temperatures on the planet should be tolerable.
00:51However, this estimate is not very precise, because it depends on various factors such as the type of star,
00:58the ability to reflect the planet, as well as its size, among many others.
01:03In addition, being located in this zone does not guarantee the presence of water.
01:07The planet must also have an appropriate atmosphere as well as other favorable conditions.
01:12To remedy this, a stricter definition was established in 2014, the habitable zone conservative.
01:20This more precise term refers to the best candidates likely to present liquid water.
01:25Otherwise, we would risk meeting too many potentially habitable planets, which, in reality, are not.
01:33The ZHC is determined by the amount of energy a planet receives from its star compared to that of the Earth.
01:39If a telluric planet receives between 40 and 85% of this energy, it is considered to be in the ZHC,
01:46regardless of its distance from its star.
01:49These planets are more likely to be habitable.
01:52And indeed, roof 715 B is located in this zone.
01:56This super-Earth gravitates around a type M star, also known as the red dwarf.
02:02This star is much smaller and less warm than our sun, representing about a quarter of its size and mass.
02:09However, if this planet is located in the habitable zone, it is actually a more suitable option for life,
02:16because red dwarfs live much longer than our sun, which is a yellow dwarf.
02:21This also means that it has more time to allow the emergence of small life forms.
02:26In addition, this red dwarf is older than our star.
02:29Our star is 4.6 billion years old, while this star is 6.6 billion years old.
02:35About a few hundred million years.
02:38This star has little magnetic activity, which puts it at risk.
02:42It does not know of strong eruptions like young red dwarfs.
02:45These eruptions can be extremely powerful and risk damaging the planets by tearing up their atmosphere.
02:51Although some planets in orbit around it have less dense atmospheres,
02:55it seems that this red dwarf has already reached a state of stability.
02:59These red dwarfs are currently privileged targets in the search for planets likely to shelter life.
03:06Our super-Earth is extremely close to its star and completes an orbit in just 19 days.
03:12Given the small size of the star and the proximity of the planet,
03:16the passage of it in front of its star occurs frequently and in a very distinct way.
03:21This facilitates the study of its atmosphere by telescopes such as James Webb,
03:25thus requiring less observation time.
03:28Speaking of the James Webb Space Telescope,
03:30it plunges us into a new era of understanding of distant planets beyond our solar system.
03:35Imagine being able to determine what gases make up the atmosphere of a planet with millions of light years.
03:41James Webb will help us to unravel these potentially habitable worlds.
03:44At the moment, he is working to verify whether Toa 715 b has an atmosphere.
03:50If this is the case, it could be more easily detectable compared to a drier and denser planet.
03:56This would arouse great enthusiasm, because it would indicate an environment conducive to life.
04:02In addition, there could be another planet in this system, also located in the habitable zone.
04:07Its existence is not yet confirmed.
04:09It is only a candidate for the non-extravagant.
04:12But if it turns out to exist, it would be comparable to Earth in terms of size,
04:16thus becoming the smallest planet observed in the habitable zone by the TESS telescope.
04:22Another fascinating feature of Toa 715 b is that it could not only house water,
04:28but also be a real aquatic world.
04:31An oceanic planet designates a type of planet entirely covered by an ocean
04:35or possessing underground oceans.
04:37These planets can only have very few emerging lands,
04:40and sometimes they can even be submerged by other liquids, such as lava or ammonia.
04:46As for the planets located outside our solar system,
04:50our current technology does not allow us to observe the water directly on their surface.
04:55Scientists focus more on the detection of water vapor in the atmosphere,
05:00which can indicate the presence of liquid water below.
05:03Of course, we are also wondering about the possibility of life on these planets,
05:08hoping that they do not take the form of Leviathan-type monsters.
05:12Our models suggest that oceanic planets could be quite widespread in our galaxy.
05:17This means that there could be many more oceanic worlds to discover.
05:22However, the most captivating part about Toa 715 b
05:26is that it is located in what is designated as the Fulton gap.
05:30If we draw up a list of planets,
05:32we will observe those that are larger or smaller than Earth.
05:36However, a void suddenly appears for the celestial bodies,
05:40measuring once and a half to twice the size of our planet.
05:44Where did they go?
05:45This gap arouses the interest of scientists,
05:48because it reveals information about the way in which planets form and evolve over time.
05:53It is not about a lack of planet formation in this size range.
05:57In reality, they often start larger and then lose part of their mass,
06:01like a balloon that is slowly deflating.
06:04This could be due to the way they orbit around their stars,
06:07which can eliminate part of their mass,
06:09like our sun, which interacts with the gas of comets.
06:13This gap contains many mysteries,
06:15and planets like our new super-Earth could provide precious clues to help us pierce them.
06:21We do not yet know if this phenomenon exists around red dwarfs.
06:25It is possible that it is a difference in density among these planets,
06:29rather than a question of size.
06:31Thus, the study of this newly discovered planet becomes all the more interesting.
06:36It will allow us to learn more about distant stars and their planets.
06:40We mentioned TESS a little earlier.
06:42NASA's TESS satellite, or Transiting Exoplanet Survey Satellite,
06:46was launched six years ago, and has since had remarkable success.
06:50NASA launched TESS because we had already identified more than 5,000 planets in orbit around other stars,
06:57mainly thanks to the Kepler telescope.
06:59However, Kepler has mostly detected large planets that do not necessarily look like Earth.
07:05We have therefore decided to orient TESS towards the search for smaller planets,
07:09of terrestrial size, around bright and close stars,
07:13which will facilitate their study through future telescopes.
07:16Here's how it works.
07:18The camera observes the stars and scrutinizes the variations in their brightness.
07:23If it suddenly decreases for a while before returning to normal,
07:27it can indicate that a planet is passing in front of the star.
07:30However, the stars can also darken for other reasons,
07:34such as eruptions or dark spots on their surface.
07:37This is why it is essential to take these data with tweezers.
07:41TESS provides us with information on the size and orbit of these planets.
07:46Then, the terrestrial telescopes help determine their mass.
07:50Thanks to these three parameters, we can understand the composition of the planets
07:54and know whether they are telluric like Earth or gaseous like Jupiter.
07:58And yes, it is better to avoid Jupiter after a night out.
08:02An example of the discoveries made by TESS is the TOA 700 system.
08:07This is where it launched its first planet similar to Earth, TOA 700s d.
08:12This exoplanet also orbits around a red dwarf
08:16and is even closer to us, about 100 light years away.
08:20Unfortunately, it is unlikely that it is habitable due to the extreme temperatures that reign there.
08:25Another great discovery took place in the HOMICROSCOPY system.
08:30TESS detected a planet about four times larger than Earth,
08:34as well as another almost three times larger.
08:38This system has become a key area for studying the formation
08:42and evolution of stars and planets over time.
08:45TESS has also observed a variety of other exciting discoveries,
08:48such as supernovas and burning worlds.
08:51At the dawn of its sixth year, we can expect even more fascinating discoveries.
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