Among the celestial objects discovered in the past 10 years, which ones are particularly rare?
Next, I will introduce to you those special celestial bodies in the universe.
J1407b star
The star name of this planet is very complicated, called "1swasp j140747.93 - 394542.6". For the sake of simple memory, we call it "J1407".
J1407 is a K-type star with a spectral type of less than 16 million years. It is a very young star. Look for this star from the direction of the Earth. It is located in the direction of Centauri , 464 light-years away.
Because it is too far away and very dark, we can only observe it with a telescope.
Recently, the star has begun to shine. Conservative estimates suggest that this star will become even more dazzling in 1 billion years. By that time, its spectrum type will change to type F or type G, becoming a star similar to the sun.
The mass of this star is about 0.9 times that of the sun, and it still has great potential to become a star like the sun.
In the universe, stars like J1407 are not that rare. It's just that it's relatively young that has attracted the attention of scientists.
Because studying such stars is very helpful in understanding how the sun evolved 4.5 billion years ago, and can even solve many mysteries of the solar system.
Much more interesting is the only planet in J1407, J1407b, which was discovered in 2012 while surveying several years of photometric data from its host star.
Five years before the discovery of J1407, people observed the continuous light attenuation of J1407. Scientists speculate that this dimming of light is likely caused by the transit of a large planet. So scientists discovered the planet using the "transit method".
In fact, many planets in the universe were discovered using the "transit method".
Scientists discovered that this is an enhanced version of Saturn, because its mass is 20 times that of Jupiter. Jupiter is already a very large planet, and this planet is actually 20 times that of Jupiter. What a huge planet it is.
In order to give everyone a better understanding of how big this planet is, scientists broke down J1407b, which is as large as 6356 Earths. Strictly speaking, such a massive celestial body is no longer a planet, and is most likely a brown dwarf .
Brown dwarfs are "intermediate" objects between planets and stars. Brown dwarfs have enough mass to initiate nuclear fusion reactions within them, but not enough mass to complete the reaction.
Scientists have been discussing whether brown dwarfs should be classified as stars or planets, or should be given a unique name.
However, so far, this planet has not shown the nuclear fusion reaction of a brown dwarf, so scientists have temporarily placed it in the ranks of planets.
Why did we say earlier that this is an enhanced version of Saturn? It's because there is also a huge ring on this planet.
The total mass of this ring is about the same as that of the Earth, and its radius is about 90 million kilometers, which is equivalent to 640 times the Saturn ring , and is only 18 million kilometers less than the distance from the sun to Venus.
That’s why we say that J1407b is an “enhanced version of Saturn.”
However, unlike Saturn's rings, scientists have discovered some "gaps" in this large ring. The largest gap is located 61 million kilometers away from the planet.
Scientists speculate that there is likely to be an orbiting planet here, about the same size as the Earth, which separates this ring.
But we don’t know whether this is the case. There are many mysteries surrounding such a planet, and this is just one of them.
The orbit of this planet around its main star is very special, and it is a very deviated orbit. And scientists estimate that its revolution period is between 3.5 and 14 years.
It seems that this planet was not born from the interior of the galaxy, but was captured by the star. Because a planet like this planet that is far away from the main star and has a slightly deviated orbit cannot be born in the galaxy.
This phenomenon also exists in the solar system. This is the case with Neptune's only planet Triton .
Triton is the celestial body captured by Neptune. It is speculated that it only left a few small "stones" around Neptune, and dispersed all other large satellites .
So, in this case, the orbit of J1407b's ring should become unstable. And, thanks to the sharp drop in gravity, the ring should disappear quickly.
Scientists successfully solved this mystery by constructing a mathematical model between planets, stars and rings.
The results show that if the ring is to be more stable, the rotation direction of the late ring must be opposite to the direction of the planet's revolution.
In fact, in the solar system, every major planet has rings, but they are all invisible. Only Saturn's rings are the largest and most gorgeous.
The rings of other planets are composed of tiny "pebbles" and "fragments". Their birth time is too short and scattered, so they cannot form new asteroids.
Recently, some scientists believe that the planet J1407b does not exist. They believe that the star of this planet is just a variable star that occasionally changes in brightness.
But in fact not all scientists think so. Most scientists still think that its stars and variable stars are very different.
Author: Xiao Abe Proofreading: Chuanchuan
#I am doing science popularization in the headlines#
