Scientists Have Discovered Two Extremely Close Orbiting Twin Stars
Remember the planetary neighborhood in Star Wars where Luke Skywalker grew up? Well scientists have announced the discovery of a similar star system where two suns orbit around a common mass centre. Such a system is called a ‘binary star’. What’s important about this discovery is that these stars by the names of HD 133131A and HD 133131B are the closest orbiting twin stars yet discovered in a binary system where both the stars are also hosting planets.
Discoveries are discoveries, even if accidental
HD 133131A hosts two planets whereas the HD 133131B hosts one. The distance between these stars as observed by a team from the Carnegie Institution for Science is not a lot. They are separated by only 360 astronomical units (AU). One AU is approximately equal to the distance between the earth and the sun and if simply stated the distance between these stars is 33 billion miles.
If we consider it doesn’t seem like a little distance right? Actually for a binary star this distance is considered very near relative to the other systems. The next closest binary system has a distance of 1000 AU between its two stars. The scientists who made this discovery weren’t actually for these stars; they were in search of rare planets that could be close to Jupiter in size.
They haven’t been very lucky in their search yet but they seem to have discovered quite a few exo-planets. These exo-planets are super-Earths and have masses greater than Earth but less as compared to Uranus and Neptune. Scientists believe that the Jupiter’s gravitational pull may have something to do with how our solar system has evolved over the years. They are hoping that if similar planets like Jupiter are discovered it would help them understand that how solar system is different from the other systems in the Universe.
Lead researcher Johanna Teske said, “We are trying to figure out if giant planets like Jupiter often have long and, or eccentric orbits. If this is the case, it would be an important clue to figuring out the process by which our Solar System formed, and might help us understand where habitable planets are likely to be found.”
The Planet Finder Spectrograph or PFS at Carnegie’s Las Campanas Observatory in Chile was used for this particular discovery. The PFS is specialized for the purpose of discovery eccentric planets, in other words large planets with elliptical orbits and longer orbital time. The planets in HD 133131A and HD 133131B’s binary system are said to be only moderately eccentric.
Being close is just one of the reasons why this system has aroused so much interest. These stars are metal poor and their mass is mostly made of hydrogen and helium. Subtle differences do exist in both their compositions and hint that these stars are not quite identical and have an unusual history. The team has a theory that it is quite possible that one of the stars swallowed some baby planets this gave it a different chemical composition. Another alternative that they suggested is that the gravitational pull of 3 large planets on the somewhat smaller planets in the system may have forced the younger planets into the stars.
These are all hunches and no one knows for sure what secrets these planets hold. “The probability of finding a system with all these components was extremely small,” suggested Teske, “so these results will serve as an important benchmark for understanding planet formation, especially in binary systems.”