"We hope to discover a paradise, but we discovered many hells."
is like the optimistic sol III natives who thought that there were tropical rainforests on Venus and that Martian creatures dug canals; when they first searched for the exoplanet , astronomers also regarded the solar system as the "template" of the planetary system.
But compared to the second earth, more other worlds are called hell, and they are still a little kind. The wildness of these alien worlds is beyond the imagination of any of the most imaginative science fiction writers.
In fact, to a certain extent, our peaceful solar system is the weird.
Survival guide for the period of red giants: Kepler 70b (exoplanet with the highest temperature)
Evaporating planet
How hot can a planet be? How does a planet survive after being swallowed?
Kepler 70b is an -type earth planet orbiting the B-type subdwarf star (sdB) Kepler 70. Because it is quite close to the parent star. Kepler 70b has an orbital period of only 5.76 hours - one of the shortest-period planets.
Although it is a nominal terrestrial planet, its surface temperature is as high as 7662K (7389°C) because it is too close to the parent star! Even exceeds the surface temperature of the sun. At this time, it is hard to say that this is a "earth-like planet"... The planet is undoubtedly evaporating.
Another planet Kepler 70c in the same system is not much better. It is only a little further away from the parent star than Kepler 70b and is also evaporating.
Kepler 70b system
In 2011, a very attractive explanation of their possible experience: they most likely were type of wood planets orbiting a B1V star . But when the parent star becomes a red giant, the two planets gradually approach the parent star in a spiral orbit. When these two planets are very close to the parent star, their outer layers except the rock core are evaporated; after the parent star left the red giant stage and became a B-type subdwarf 18.4 million years ago, these two planets became the current terrestrial planets and orbited the white dwarf . [1
Nothing is more attractive than this strange and desperate fate.
From Kepler 70b, Kepler 70
Star or planet?
Interstellar roller coaster: HD 80606 b (exoplanet with the largest orbital centrifugal rate)
What bad thoughts do blue planets have (laughs)
nothing is more exciting than a solar system-level roller coaster: HD 80606 b orbital centrifugal rate up to 0.93 can meet anyone's needs.
roller coaster!
On it, you will dive from the ariel point of 0.876AU to the periel point of 0.0301AU, and experience the ultimate roller coaster fun.
The tours you can experience include and are not limited to:
A, impressive light changes: at the arising point, its light amount is equivalent to that of the earth, but at the perihelion point, it is 800 times that of the earth.
B: The ultimate sunrise experience: Feeling at the perihelion is equivalent to 30 times the size of a star seen on Sol III.
C, unforgettable cooling: When approaching the perihelion point, the surface temperature will rise from 800 K (500°C) to 1500 K (1200°C) within 6 hours!
D, unprecedented storm: sharp heating has made planetary climate change quite fierce. Computer model predicts that the planet's sharp heating will produce supersonic shock wave storm
with a speed of 3 miles per second (4800m/s) for you to choose from, and you will get a full personal insurance - of course, there seems to be no bad reviews~
"On the Heating and Cooling of Planets"
HD 80606 B weather simulation and oscillating waves storm
holes in the sky: Kepler 1b (exoplanet with the lowest albedo)
black, really black
How black can a planet be? When
discovered Kepler 1b, the situation seemed not that bad, until it was taken by the consecrated photo of the Kepler telescope, so the Kepler 1b number was obtained.The first important result of Kepler 1b observations of Kepler 1b by
Kepler task is that its geometrical albedo is extremely low.
2011 study pointed out that if the day-night brightness comparison of the planet is caused by geometric albedo, the albedo value is 2.53%; but the model simulation points out that the radiation from the day-half hemisphere accounts for the vast majority of the total radiation, so the real albedo should be much lower than the original speculation. The model predicts that the albedo rate is less than 1%, while the value that best matches the observation is 0.04%.
What does this mean? In layman's terms, the albedo is lower than that of coal and black acrylic pigments, yes, it's even darker than the pigments on your table. When placed in space, we can't see anything except the day hemisphere has a terrifying red spot because of the high temperature - because it is too dark, it absorbs almost all the energy it receives - and the planet is like digging a hole in space.
This planet actually has a cartoon image, outrageous:
at your fingertips: Kepler 36b and c (the lowest ratio of semi-major axis between planets)
female star spectrum: G1IV
semimajor axis: 0.1153AU and 0.1283AU
Radius: 1.498 and 3.679 Earth Radius
Mass: 3.83 and 7.13 Earth Mass
This is almost a traffic accident in the universe: two super earths/mini Neptune are locked in orbital resonance of 7:6 [4], and meet at close range about 5 times the distance between the earth and the moon. Looking from the inner planet, the outer planet will be surprisingly larger every 97 days: 2.5 times larger than the supermoon seen on Earth. The strong gravity is enough to cause intense geological activity on Kepler 36b, tearing its surface.
What is more interesting is that the density of Kepler 36b is very high (6.8g/cm³), and it is very likely that it is a Hot Neptune that is heated and lost to the outer layer due to the orbit too close to the parent star. [5]
Heat expansion limit: Kepler 51b (exoplanet with the lowest density)
blueberry flavor, lemon flavor and strawberry flavor, and about the same size as Jupiter
How soft can the gentlest planet be?
The three planets of Kepler 51 system are colorful, like three marshmallows.
They are indeed marshmallows, very young (500 million years old) and the heating from the mother star makes them extremely bulging. The third generation wide-area camera (WFC3) on the Hubble Space Telescope recorded the transits of the two planets, Kepler 51b and 51d respectively. Through this information, as well as the latest updated stellar parameters, the reanalyzed Kepler data, scientists found that the density of the three giant planets was very low.
results show that the density of the three planets studied in the Kepler 51 system is lower than 0.1g/cm³, which is equivalent to the density of marshmallows, thus obtaining the nickname of the super-bloated planet.
Next research shows that these three planets have a pure hydrogen and helium atmosphere, among which Kepler 51b is the most exaggerated, with a density as low as 0.03g/cm³ (the other two planets are only 0.03g/cm³ and 0.046g/cm³). For comparison, even Saturn has a density of 0.687g/cm³.
and even their density would be lower hundreds of millions of years ago. However, as they evolve and gradually lose part of the atmosphere (Kepler 51b will lose more than two-thirds of hydrogen and helium), it finally stabilizes in the normal, mature planetary density range after 5 billion years - although basically still at the lower limit of the normal range.
Stars are laid off and re-employed: Little Leo YZ b ( orbital cycle shortest planet)
Imagination of Dog Reap AM-type variable star
What if a star loses its mass in some way, so it is too small to be called a star?
Little Leo YZ is an AM Canum Venaticorum variable (AC), a nova variable star in , companion star will be absorbed by white dwarfs because it exceeds Loxi halve .(For this kind of variable star, please refer to a brief introduction to variable star - Zhihu (zhihu.com))
is said to be a binary star. Strictly speaking, the companion star of Little Leo YZ is not a star, but a substellar object with a mass of 35 Jupiter - orbital inclination as high as 82°, and it circles around the white dwarf that has grown to 0.872 Sun mass every 28 minutes. Although its mass is far less than that of the white dwarf, it is still larger than that of the white dwarf.
This planet is still trapped in the accretion disk where the matter has been pulled out, which means that it will cost 996... if it is laid off.
Extremely cold land: OGLE-2016-BLG-1195Lb (the lowest temperature exoplanet)
This star is too weak...
OGLE-2016-BLG-1195Lb is an exoplanet about 13,000 light years from the earth. The parent star is OGLE-2016-BLG-1195L. The planet was discovered in 2017 by the Korean Institute of Astronomical Research and the Korean Microlensing Telescope Network (KMTNet) and the Spitzer Space Telescope as a microgravity lens. The mass of
OGLE-2016-BLG-1195Lb is similar to that of the earth, and its distance to the parent star is equivalent to that of the sun-earth distance. But unfortunately, the star it orbits is an ultra-low-cool dwarf (Ultra-cool dwarf) [9] with a mass of sun. The temperature of this type of star is about one-third of the temperature of Kepler 70b above. Therefore, the surface temperature is only a pitiful 31K (-242°C). In fact, at this temperature, there is no longer much gas that can form an atmosphere because it is all frozen into a solid state.
to pieces in the grave - WD 1145+017 b (the smallest mass exoplanet)
What happens to the earth after the sun dies?
This is the horror preview of the distant future: a planet is evaporating by a white dwarf.
WD 1145+017 is not a magical thing. The white dwarf has a mass of 0.6 sun mass, a radius of 1.4 times the Earth's radius, and a surface temperature of 15,900K. It is a typical white dwarf with an age of 175 million years. According to recent research and its mass, the star may have been an early F-type main sequence star (spectroscopic type F0) before becoming a red giant.
Although this system is not a Kepler target of interest, it is in the observation field - it turns out that the white dwarf has strong absorption spectrum lines of the following elements: magnesium, aluminum, silicon, calcium, iron and nickel. These elements, usually found in rocky planets, pollute the surface of the star through the mixing of stars, and take a million years to disappear from the field of view - the matter that makes up the planet is falling onto the star.
Next, WD 1145+017 b was found in the fragments. This poor celestial body had an orbital period of 4.5 hours [11], which is located within a distance that will be torn by the mother star, so it should be the remains left by the torn planet before this star became a white dwarf. The light change of the white dwarf also shows that there are some fragments of about 90km in the orbit of WD 1145+017 b - these fragments undoubtedly tell us how the dead star had tear its own planet apart.
As for WD 1145+017b itself, this satellite -sized wreckage is being heated and evaporated under the radiation of white dwarfs, which will be completely erased within the next 100 million to 200 million years.
Nirvana in the Ashes - PSR B1257+12 A (the smallest exoplanet)
The feeling of receiving high-frequency disinfection services at star-level every day, PSR B1257+12 A and the other two planets that also surround this pulsar are very clear.
PSR B1257+12 A is the first exoplanet discovered by humans. The reason is actually very simple: it orbits a millisecond pulsar 2300 light-years away. The pulsar itself has a very accurate cycle, and the existence of the planet will interfere with the pulsar's radiation and produce abnormalities - so that very small celestial bodies can be detected.
has the following benefits on this planet:
1. Gravity is smaller than that of the earth and can jump very high; at the same time, the planet is smaller and does not need to go far. The temperature of
2 and 260K is not bad, and you can also appreciate pulsars like searchlights.
3. 160 disinfection per second allows every chromosome of your cell to bathe in radiation.
service provider tips: One-way trip, no insurance, you will be responsible for the consequences.
What's more interesting is the source of this system: it's really incredible that pulsars have planets, because supernova is so devastating. One guess is that these planets were formed after the collision of two white dwarfs.
Therefore, this planet obtained the name Draugr - an undead creature derived from the North mythology.
Giant Searchlight
One-way trip, no insurance
Inflatable planet: HAT-P-67 b (exoplanet with the largest radius)
How big can the largest planet be? It is not the heavier the planet, the bigger it is.
Generally speaking, giant planets with weak gravity and close to stars are the best candidates, just like HAT-P-67b. This planet, which is only 0.065AU from 's parent star , expanded to 2.08 times the radius of Jupiter after being heated to a high temperature of 1903K - can arrange 23.4 Earths horizontally, which is really amazing in size considering that the smallest star is only 5 times the size of the Earth's radius.
means the temperature is a little higher (it seems to be more than a little bit).
This giant planet that expands due to high temperatures has a better name "Puff Planet", which is more interesting than "Hot Saturn".
Polar Orbital Planet: COROT-4b (exoplanet with the largest orbital inclination)
For a hot Jupiter , 9 days is quite normal for a year, and a 90° orbital inclination [15] is not very normal. This is almost the behavior of polar-orbit satellite , and it is unusual.
The next question is, what disturbances made this planet appear in such a strange orbit?
The longest year: COCONUTS-2b (the longest planet with the semi-major axis)
What is more terrifying than loneliness?
Imagine a world where the sun and does not exist, with a year of 1 million Earth years...
That's right, COCONUTS-2b (coconut-2?) can be said to be the loneliest of all planets with mother stars, with a semi-major axis of orbits of 7506 astronomical unit . At this distance, M-shaped stars look no different from ordinary stars, and it takes 1101369.9 years to orbit the star. In comparison, human beings had not developed civilization 1.1 million years ago. The semi-major axis like
makes it easy for astronomers to distinguish it from the dark and weak parent star and discover its existence using direct image method.
