When planets are in the wrong order. (LHS 1903)

"LHS 1903 is a small red M-dwarf star that is cooler and shines less brightly than our Sun. Scientists used telescopes in space and on Earth to discover four planets orbiting LHS 1903. With those telescopes, they classified the three closest planets to the star as the innermost being rocky, and the two that follow it gas giants. Credit: ESA" (ScitechDaily, This Alien Solar System Doesn’t Follow the Rules – and Scientists Are Intrigued)

“LHS 1903 is a red dwarf star located about 116 light-years from Earth in the constellation Lynx, near 21 Lyncis. It is thought to be a member of the Milky Way's thick disk.” (Wikipedia, LHS 1903)

“It hosts four known exoplanets. Its planetary system has been described as "inside-out", as instead of the usual pattern where gas planets tend to form further out, its planets are arranged in a configuration where the innermost and outermost planets are rocky, while the middle planets are gas dwarfs.”(Wikipedia, LHS 1903)

“In the late 20th century, scientists often described planetary formation using our solar system as a template. In that view, small rocky planets form close to the Sun, while gas and ice giants form farther away. However, the discovery of more than 6,128 exoplanets across 4,560 systems, along with unusual types such as hot Jupiters and planets orbiting pulsars, suggests that our solar system may not be typical.” (ScitechDaily, This Alien Solar System Doesn’t Follow the Rules – and Scientists Are Intrigued)

“Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter (i.e., Jupiter analogues). But they have very short orbital periods (P < 10 days). The close proximity to their stars and high surface-atmosphere temperatures resulted in their informal name "hot Jupiters.” (Wikipedia, Hot Jupiter) 

Could planets change their place? This is a good question. The LHS 1903 is the red dwarf. The M-type star is far less bright than our Sun. The mass of that star is far lower than that of our Sun. That star has a planetary system of four known planets. The planetary system of LHS 1903. Fits in the Mercury trajectory. If we compare it with our solar system. 

The planet’s order in this system is interesting. The inmost and outmost planets from the star (LHS 1903, B and E) are rocky planets. And the center planets (LHS 1903 C and D) are mini Neptunes. Those mini Neptunes' mass is about six times that of Earth. And their diameter is about twice Earth’s diameter. 

“The location of the LHS 1903 system in the constellation Lynx. Credit: Stellarium.” (ScitechDaily, This Alien Solar System Doesn’t Follow the Rules – and Scientists Are Intrigued)

The LHS 1903 planetary system (Wikipedia, LHS 1903) 

Also, those two rocky planets have a very large mass. The fact is that. When we see the table of that solar system. We see. The outermost planet E is almost as massive as planet D, and it's also more massive than planet C. So, could that mean that the LHS 1903 is trapped some of those planets around it? If we think of the possibility. The planets changed their places. That requires that something. 

More massive than LHS 1903, it formed. Some kind of mass center. And then turned the entire solar system around. Could some. A very small thing, like a small black hole. Travel between those planets? This kind of thing could spin. The planetary system around that mass center. 

 In planet formation models, the rocky planets are nearest. The reason for that is the solar wind. That blows the light elements away from around the planet. But there is one thing that makes LHS 1903 interesting. The rocky planet is massive. That means it could also lose its gas layers. The cosmic event, like some kind of particle beam, can strip the light elements from around that planet. 

The massive “hot Jupiters” can be very close to their star. If there is a solar system. The innermost planet is a “hot Jupiter”. And others are lighter rocky planets. That can form in a situation where the star “robs” other planets than the “hot Jupiter” from other solar systems. In cases of “hot Jupiters,” the planet’s massive gravity can resist the starwind. 

https://scitechdaily.com/this-alien-solar-system-doesnt-follow-the-rules-and-scientists-are-intrigued/

https://en.wikipedia.org/wiki/Hot_Jupiter

https://en.wikipedia.org/wiki/LHS_1903