Binary stars are also known as binary stars, a term coined by Herschel, the first president of the Royal Astronomical Society.

A binary star is more of a physically related binary star, where two stars each orbit a star system with a common center of mass.

As Yang Yiyi said, the Cowherd Star and the Vega Star are not joint stars.

The bigwig Herschel also discovered Uranus and its two moons through a large reflecting telescope of his own design, compiling the first binary star and star catalog.

Therefore, when Chen Zhou and the others searched for literature, they first thought of this person.

The three of them searched for the required documents according to their respective goals.

[In a binary star system, the gravitational pull of one star is provided by the other star, and vice versa.] The ratio of their centripetal acceleration is the inverse of their mass......]

Chen Zhou took out a scratch paper and recorded this message.

From this, the ratio of the centripetal acceleration of the binary system in the problem can be directly obtained.

[The planet moves in a uniform circular motion around the star, and the distance of gravitational force is exactly the orbital radius of the planet's circular motion. However, the distance of gravity in a binary star system is different from the orbital radius of the binary star's motion, and the angular velocity and period of the two stars in a binary system must be the same when they move in a circular motion. The ratio of their linear velocities is the same as the ratio of the radius of their respective orbits......]

Yang Yiyi also recorded the corresponding element information while searching.

9 p.m.

Chen Zhou, Yang Yiyi, and Fang Jieming began to summarize the information they had collected.

After that, Chen Zhou began to assist Yang Yiyi in relevant theoretical analysis.

Fang Jieming stepped aside, ready to rest.

For him, all he needs to do now is to take a break, and his working hours are not yet up.

"There is so little information on this question that even the key elements are incomplete. Yang Yiyi said.

Chen Zhou also frowned, then stretched out, and said with a smile: "It's okay, follow the information we found." This can be regarded as a test of the event itself. ”

Yang Yiyi nodded, pointed to the recorded information with a pen, and analyzed: "There are a total of 5 kinds of orbits of planets around double stars, which are large peripheral orbits, small peripheral orbits, eccentric peripheral orbits, complex peripheral orbits and internal orbits. ”

"And the large outer orbit is the simplest of the planet's orbits around a binary star, because the planet is very far away from the binary star, so that the gravitational pull from the double star will approximate that of a star with a mass after both of them. In this case, the planets will orbit the binary star simultaneously in a normal elliptical orbit. ”

Chen Zhou thought for a while and said, "This kind of situation is indeed the simplest, but such a planet will be very far away from the mass center of the binary star. ”

"That's right. Yang Yiyi continued, "Among them, it is also necessary to consider the forward and retrograde issues of the planets......

Speaking of this, she glanced up at Chen Zhou before saying, "Coupled with the analysis of other detour tracks, the amount of calculation in this is huge. I want to share it for you. ”

Chen Zhou looked at Yang Yiyi, hesitated for a moment, and nodded slowly.

Seeing that Chen Zhou agreed, Yang Yiyi smiled.

The two went on to analyze the planet's orbit around a binary star.

After peeling back the cocoon, the physical principles are basically clarified.

Now it's time for the theoretical calculations.

Chen Zhou raised his hand and looked at the time, it was already one o'clock in the morning.

The sound in the computer room is not as noisy as it was at the beginning.

Many people lie on their computer desks and start sleeping.

Chen Zhou turned his head to look at Fang Jieming, who was also lying on the computer desk, and smiled slightly.

Yang Yiyi also turned her head to look at the senior who seemed to be asleep.

Regarding the part of the calculation around the orbit of the double star, Chen Zhou handed over the part of the large peripheral orbit and the small peripheral orbit to Yang Yiyi, and advised: "Don't force it, go sleep for a while if you are sleepy." Don't worry, leave the problem to me to solve. ”

Yang Yiyi nodded slightly.

[A planet orbiting a binary star in a retrograde elliptical orbit with a high eccentricity has an orbital period of about 12.5 times the binary period, and the maximum distance will reach 10 times the distance between the binary stars.] The elliptical orbit will drift around the core of the binary star in the same direction as the planet's revolution......]

Chen Zhou started from the eccentric peripheral orbit and gradually entered the state.

Analyze the problem, ask the problem, solve the problem.

There is no sense of barrier to the idea, and the calculations are very smooth.

After the problem of eccentric peripheral orbit was solved, Chen Zhou was not in a hurry to solve the complex peripheral orbit problem.

Instead, he thought about the problem of the planets going forward and retrograde that Yang Yiyi said earlier.

He holds a pen and habitually points scratch paper.

"Stability?" Chen Zhou thought of the word.

Since a binary star system is called a system, it is because two stars orbit around a common center of mass in their respective orbits.

Therefore, how to maintain this stability after the planet has intervened is the key to the problem.

In the final analysis, the ultimate goal of this question is the stable coexistence of binary star systems and planets.

Chen Zhou glanced at Yang Yiyi and patted her gently.

Yang Yiyi stopped the pen in her hand and looked up at Chen Zhou suspiciously.

Chen Zhou said: "Yiyi, we need to solve the problem of forward and retrograde planets first, so that unnecessary calculations can be reduced. ”

Yang Yiyi pondered slightly, then picked up her scratch paper and glanced at it, and handed it to Chen Zhou.

Chen Zhou took it and looked at it for a while, put down the scratch paper, and said, "That's right, it's this thing." ”

On Yang Yiyi's scratch paper, the relevant calculations of the planet's retrograde have been completed, but the calculation of the retrograde cannot be carried out stably.

Originally, Yang Yiyi calculated the planets in direct motion first, but it turned out to be calculated, which felt a bit problematic.

He paused for a moment and turned to calculating the retrograde planets.

Yang Yiyi said: "It should be that the planetary retrograde will affect the stability of the binary star system, and eventually lead to the imbalance of the binary star system. ”

Chen Zhou was slightly surprised, but she didn't expect that she had already thought of this.

Chen Zhou thought for a while and said, "Let's compete, who will solve this problem first, how about it?"

Yang Yiyi looked at Chen Zhou and smiled slightly: "Come on, it's like doing questions in our summer vacation competition." ”

At the same time, the two of them began to look up relevant literature on their computers.

It took a lot of time, and Chen Zhou finally deduced the relevant solution information according to the information he found.

[If the planet is not retrograde but prograde, the whole system will not be able to exist stably, and the planet will either be swallowed by the star or fly out. This is because the gravitational field strength fluctuations experienced by the direct planets are the same as the amplitude of the retrograde planets, but the period is longer, and the longer period will weaken the effect of stabilization, and eventually lead to an imbalance ......]

Chen Zhou glanced at the conclusion written on the scratch paper, and when he was about to give it to Yang Yiyi, Yang Yiyi was looking at him sideways.