hello this is a question of science. i am aleksey semehav throughout almost the entire history of mankind and almost all the history of science, our cosmic house of the sun from the mountain planet was perceived as something absolutely unique , the only and unrepeatable data in the singular. we didn't even imagine . how often can planets be found around other stars. now we know much. more we discovered thousands of exoplanets. the question is what conclusions we have drawn about

the structure of the cosmos, about the possibility of existence. anywhere on these planets. and as a result, we now look at our good old eight planets of the solar system in a new way. my guest is candidate of mathematical sciences, junior researcher of the laboratory, 51st department of planetary physics of the institute of space research of the russian academy of sciences vladislava and gorevna vladislava igorevna ananyeva hello, thank you very much for taking the time to come to the studio. hello alexey thanks to what miracle against the background of bright stars? well, they, of course, do not seem too bright to us, but nevertheless, in comparison

with a planet that does not itself glow, like we catch a speck of dust on the planet against the backdrop of a spotlight. you are absolutely right for a very long time the question of whether there are planets around other stars remained unanswered, because the planet is very difficult to detect. and it's not a miracle. this is the development of observational technology, which at the end of the 20th century. achieved that we were able to register very weak movements of the star caused by the planet, that is, the method of radial velocities. what is it based on is based on the fact that both the planet and the star revolve around common center of mass. we do not see the planet. we see that the star. as it rotates it fluctuates its radial velocity changes and we can measure it by measuring the slight shift of the spectral lines in its spectrum. let's go back then to how we discover them historically. the first planet. the sun has a similar

star. it was discovered by the radial velocity method. for a very long time, the accuracy of measuring the radial velocities of stars was measured in kilometers per second. for example, uh, the sun. the center of the jupiter sun system revolves around bari at a speed of about 13 m / s. earth causes the sun to revolve around a common center of mass at a speed of 9 cm/s. therefore, these values ​​were crawling at approximately the same speed, approximately like this, that is, for a very long time we could not discover anything, because our observational technique did not allow us to do this. finally, at the end of the 20th century. development of spectrographs. reached the level that the accuracy measured by the radial velocity of stars comparable to the sun was approximately 15 m/s. and at the end of the twentieth century. two research teams at once. the so-called

california band and girl band american europeans began to measure radial velocities in the nearest bright, and directly with a target directly with that target. yes, for that very purpose. there are planets, the radial velocity method was the only one until 2000, that is, during the first 5 years, the study of the exoplanet transit method is based on the fact that if the orbit of the planet is located on our edge. then in the system it is possible, the so-called transits, that is, the regular passage of the planet through discussion. yes, this leads to a slight but detectable decrease in the brightness of the system, which has characteristic square shape. what percentage are characteristic values? it's very difficult to measure it, yes, but if we take giant planets comparable in size to jupiter and a star comparable in size to the sun, then this is about 1-2%. still. this is

a large value, which is easily registered even through the earth's atmosphere. well, if we consider the earth, which is 11 times smaller than her peter, then the earth's passage across the sun's disk will cause a decrease in the brightness of the system during transit by only 84 million fractions, that is , not every alien will find the earth in ours. yes, for this you have to take your telescopes into space and they should be lucky to observe, uh, the solar system, just from the plane of the ecliptic. otherwise, the earth will pass above or below the solar disk and there will be no transits and the planets will not be discovered, unfortunately, by the transit method. with all its virtues. there is a major drawback. the probability of a transit configuration is inversely proportional to the distance between the planet and the star, and for a typical hot jupiter it is about 10%. but for the earth and the planet,

located at a distance and comparable to the distance from the earth to the sun, it falls, well , up to about half a percent, most planets are not in transit. this is a major disadvantage. that is, we can clearly see when a large planet, such as jupiter, passes very close to the star. they are called hot jupiters because they are big and hot. not because they are hot inside, because they are close to the star, but they are hot, but they are heated by the star. it's hot there, it's hot there, like mercury is only hefty. planet i would say much closer to mercury mercury is far enough away. hot peters often rotate at a distance of literally several stellar radii and make one revolution, some earth days. yes , it happens that in a few hours yes, it happens that the planet makes a revolution, that is, in fact , its year is less than one earth day. no, but

these two methods. yes, do they complement each other or what? yes, they complement each other perfectly, if both methods can be applied to the same planet, then we can measure both mass and radius and orbital period eccentricities. and, accordingly, calculate the average density of the planet. this means that it is very important to determine its chemical composition , you said that there is no method, since we do not see the planet, but we see indirect data. we don't know everything. we don't know the inclination of the orbit. e in advance e we er, well, this is, firstly and er, each method has its own limitations and determines only some parameters of the orbit, but not all, well, the period is obvious, so we can, probably we can about one and the same planet to be sure that we are talking about the same planet, probably er, at least, maybe you corrected me here. yes, in order to fix a transiting planet, it is not enough to see one transit, it is necessary to see three transits in a row, because if

we saw one transit, the planet passed well along the disk of the star. we saw another transit does not mean that we know the orbital period, because it could be two different planets. one passed the other passed and these are the mistakes. they were in the history of exoplanet research, when two different planets were mistaken for nu. and finally, when you're expecting a third transit at three, if it happened, then yes, the planet is discovered, at least a transit candidate is open in order to make sure that this is really a planet we need to measure its mass, because , uh, hot jupiters have the same the same size as brown dwarfs. these are objects that are lighter than stars, but heavier than planets , an intermediate type of objects and also low -mass stars also have the same size, so how can we find out what is not. well, nothing speeds, we measure

the mass by the transit method. we measure the radius. we know the average density. we know what kind of object in front of us is a planet or a brown dwarf. or even a low-massive star, it happens like this. what percentage, uh, of all , let's say, of exoplanet candidates that are now known by two methods , has been studied reliably successfully. how often we are so lucky with both methods not too often eh. well, let's say, i think that 10-15 percent of all planets have been studied by two methods. and as a rule, this is first, uh, they find a transit candidate, that is, they find a transit planet, then measure its mass, sometimes it happened very rarely, on the contrary. the planet was discovered by the method of radial velocities, and then op. we're lucky, she's a transit. and what else do we have in stock, just in case. well , for example, some planets can be seen in the snow how? well, this is important, so far, not

one planet has been discovered in reflected rays, but there are massive hot young giant planets that shine with their own light. they are heated to high temperatures, but one and a half to two thousand degrees, sometimes thousands of degrees and uh, when we point at this system infrared? on a good angular resolution, we see two sources, a bright star and a faint source next to a planet. this is e. well, it's called imaging or image detection. and now, uh, the coldest planet that was thus discovered is the giant planet of the stars 504 and the coldest is how much somewhere 500 ° c, it’s really very cold, because we see in this way first of all those who are hot and glows from the fact that he is hot, he glows himself just because there is no star, but

it glows because it's hot, right? and that's all, unfortunately, only young massive giant planets, which have not yet cooled down and which are far enough away from their star, are discovered by this method. otherwise, the light is a weak light, uh, the planet is lost in the rays of the star. here specifically, the planet gadzhi-504b was removed from its star. at a distance greater than the distance between the sun and neptune. wow, yes, otherwise it would be here, it would be lost in the rays of all methods all e 3 methods. no, there are many more of them, but 95% of all of them are for planets, discovered by only two methods, the radial velocity method and the transit method , these are two workhorses. uh, the modern method of obtaining direct images is very promising, but so far. he is limited by the shortcomings of instrumental technique, that is

, just as before until the end of the 20th century. we were limited by the insufficient accuracy of petrographs. now we are limited. uh, let's just say, a the impossibility of isolating the weak light of the planet against the background of a very bright star, which at a small angular distance there is a contrast between nu the sun and jupiter of the order of nine orders, that is, the sun is brighter or peter a billion times, and the planet of the earth, like there are still an order of magnitude two. unfortunately. so far this problem has not been solved, not a single planet has been discovered in reflected rays. well, we can now argue that a rare star does without a planetary system. a rare star of a non-planetary system in fact. we know the abundance of planets. only approximately up to the stars of the middle class, f which are brighter, heavier, more massive than the sun, but one and a half times uh-huh

. yes, but we don't know. uh, do they have planets and planetary systems, how are they different from planetary systems? like red dwarf stars, well, one might suspect that they differ greatly, because, of course, the properties of planetary systems are highly dependent on the properties of the parent stars. and as a result of these hmm workhorses gave us how much how much what abundance? i cannot give you an exact answer to this question, because new exoplanets are being discovered. well , almost every day a rare week costs a few more new exoplanets. or confirmation he's by now the number of known exoplanets, approximately exceeded 5.4 thousand exoplanets, roughly speaking, until we finish talking, they will not open yet, it is quite possible. the first planet in general, the first

m exoplanet outside the solar system , was discovered in 1992. these were two planets around the pulsar at that time. this is an exceptional case, because since then several thousand pulsars have been studied, and only three of them have been discovered. at least some planets. that is, e is, in a certain sense, uniqueness, in general, pulsars. i just to clarify, this is a neutron star. so this is a kind of exotic, this is an unusual star for them. and this is something very special and rather exotic situations and conditions. it's pretty exotic, let's not do anything periodically, that is, uh, usually neutron stars. no, well, it so happened that these are the neutrons of a star, there are two planets and they were discovered due to the fact that the pulse rotates around its axis and emits. e, the pulses of radio radiation and the period of these pulses withstand with great accuracy, comparable to the accuracy of an atom. hours and now, if

the planets revolve around the pulsar, then in fact we return to what we talked about, that it is not the planet that revolves around the pulsar a and the planet and the pulsar revolve around a common center of mass. and this is the rotation of the pulsar around the brecencenter. e was detected due to the exceptional accuracy of his radio pulses , the slightest slightest glitch. here in this accuracy it was already possible to fix and understand that this is a planet, the periodicity, then slightly increased, then slightly decreased, and this was interpreted. like what's around the pulse two planets revolve. so here we see, uh, these almost 5 1/2,000 exoplanets by year and by method, and here are the green columns. they tell us that the main thing is this is a transit and what other conclusions can we draw here? looking at the big picture in the totality of everything that we have learned. we can say that the world of the planets is exceptionally diverse

, much more diverse than the world of the stars. there is nothing much more diverse than the world in solar systems. nathan, on the other hand. there isn't. it is there that there are many types, planets that are not in the solar system. eat planets resembling the planets of the solar system. but we can say that there is no standard, that is, each planetary system is unique in its own way, and a lot of what we now know was simply unthinkable before, the most violent fantasy of the writer, science fiction writers, could not show us what we see, what we saw in the solar system. there are no hot peters in the solar system. there are no hot super-earths, then there are five times larger than the earth, which is also very close to the star. yes, more than five times. and about one and a half to two times more sizes, but these planets are

lava ocean lava ocean, that is, they are heated so little. they are turned to their star with only one side. on the one hand, we have the lava ocean, and on the other hand, the frozen desert in the solar system, the orbits of the planets are close to circular, but hmm, the known giant planets, whose casiosite is more than 9/10, that is, they approach their star very close at a distance of several radii , and then fly away at about the distance of the earth's orbit. well, that is something like a little, like our comets. yes, the elongation is comparable to the eccentricity of the comet orbits. and no one suspected this either. everyone expected that, as it were, a calm formation of planetary systems would bring planets, both to the solar system and to other stars, and the circular one turned out not to be. this is not so, moreover, in the solar system, the planets rotate approximately in the same plane in one direction

; there is an exoplanetary system in which the planets rotate not only in different planes, but planes perpendicular to each other. and this despite the fact, forgive us for in general, it is rather not very easy to determine the wax plane in which the planet orbits the planet transiting it can be done yes , there are no planets in the solar system. than the mass lie in the interval between the mass of the earth and the mass of the wound. this is 14 masses of the earth, however , other stars of the planet of this intermediate, such as the super earth named neptune, are very common. in what sense, this is the most common in a sense, the most common, as shown by space telescopes in the name of kera, most of the planets are exactly like this, this is not a planet with radii two two and a half three radii of the earth at the same time they can be quite light. you know that they are not made of stone. yes, they are not

stone, they are surrounded by extended hydrogen gel atmospheres. it is little discovered by the planet oceans and oceanides, which are close in chemical composition to the composition of satellites. jupiter ganymede. and calista can be imagined as an iron-stone core surrounded by a huge water mantle, a mass that it can make up. well, half, for example, the mass of the planet, i can't help but ask very briefly. how do we we know. we barely made out the planets. how do we know about the iron core and the water around, if we know the mass of the planet, if we know its radius, we can calculate the average density, if the average density is comparable to the average density of the earth or higher, this means that the glands of the stone planet are nothing else. she just can't be. if we see a planet with a mass, for example, one and a half masses of the earth, well, which radius e, the entity exceeds the same one and a half radii of the earth, and

it is located close to its system. she has there can't be a hydrogen atmosphere, because the whole atmosphere is hydrogen. cosmos will be better for a long time. this means that in addition to iron and erikats, stones, which, for example, are made of on the earth of venus, mars, mercury, its composition includes the so-called volatile substances, volatile elements. well, mostly yes, but other er. other ices are methane, ammonia, possibly carbon monoxide, carbon dioxide, but mostly, right? there are no such planets in the solar system, that is, the world of planets. so diverse that it is impossible to collect the entire zoo in one system, how to this refers to the fact that there are no regularities in the formation of planetary systems of some kind, like once they explained a very simple thing. here are stone planets near the sun, because the sun blew away all the gas, and where it is cold, they settled there. now you

are telling a completely opposite story of hot jupiter and rushing around the stars and none of them blows anything away. they keep themselves perfectly there is no unity in the arrangement of e planetary systems. yes, there are certainly some patterns, but the general plan of the general architecture that would be. well, true for most exoplanetary systems. there is no such thing, does this mean that the whole story is about how we model, and the emergence of the solar system, how do we understand its formation? it requires, as it were, a more balanced approach and some revision. that is , here there is here there is food for thought material for work. yes? certainly well, in fact, the development of cosmogonic hypotheses that would explain the formation of the solar system is also constantly evolving. it's not something frozen. there is a lot of work there. e is happening right now and

still hmm well collide hypotheses. it's not something that's been punched out. well, we can say that the formation of planetary systems. e, depends on the conditions in which the planetary disk was formed in this, whether it was formed in some quiet calm place where there are no bright stars nearby and stimulated either the process, er, the star of education and the planet of education. this is a single process, close adult new or close collision of neutron stars with the formation of a black hole. a lot depends on this, the mass of the disk, there are massive disks, there are more rare massive disks. uh, dust-rich planets are formed, giants more rare discs, will lead to the formation. let's just say the planet neptune or a super-earth.

it depends very much on whether this disk was perturbed by the raid of an external star, for example, or by a companion many stars are binary and when uh there is a massive satellite it is with you in the gravitational field it can spoil the disk and it can be tilted relative to the axis, star rotation. here, too, surprisingly, many hot jupiters rotate in polar or retrograde orbits. yes, or even in the opposite direction or even in the opposite direction, that is, uh, this cannot be, if we have a calm one like this. calm evolution, when it does not affect the planetary system. a summing up ah, looking at the solar system. what is your feeling? i understand that this is not a strict question, however, how lucky we are. here in such a rather dedicated, as i now understand you, if i

correctly hear quite a dedicated rather special planetary system. well, let's just say the search for analogues of the solar system. it's one of my favorite topics. hmm, you could say that about fifteen to fifteen percent of the sun-like stars. there are giant planets in wide orbits in orbits. and if these stars don't have massive planets next to them. no hot moons, no planets in orbits comparable to the orbit of the earth, most likely, there are small planets of the terrestrial planet, of the type that we simply don't see yet, that is, we can conclude from this that approximately, well, ten percent of sun-like stars. there is a planetary system similar to the solar one, we are not a standard, but we are not some kind of unique case, we are some kind of average case.

there is a planetary system, for example hmm compact densely packed, where four five six planets the orbits of the planets are deeper, the orbit of mercury the solar system is empty deeper closer mercury is nothing, but there are stars there is a planetary system where there are several planets we pack often they are connected by orbital resonances , that allow them. uh, stay steady. because if, uh, the planetary system is unstable, the planets can approach traditionally interact. and then their orbits become, that is, the planetary system becomes agitated, hacked , some planets can fall on a star. some may collide with each other some may leave their system and fly away. just drive into the galaxy and swim. there is free without any star. we are more interested in all the earthly planet, type. i want to wish you all. to be by

there are more opportunities for us to discover perfection or methods and find something similar to the land of the distant. and it is better for not too distant stars. thank you very much. thanks for your interesting story. all the best, goodbye. i wanted to tickle the nerves of vices ;

a sign of four without water, ready to order the most with musical notes of mushroom - this is from game and a bottle of naphtha and a bottle of rain and i, perhaps, sour cabbage soup hmm

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