The Kepler-11 system, as imagined from Above, is a “peas-in-a-Pod” planetary system. Credit: Nasa
Astronomers have discovered more than 300 Exoplanetary Systems that have Three or More Known Planets. Most of these planets are about the same size and spaced close together, earning them the monkey “peas in a pod.” They also orbit near their stars, in many cases closer than mercury is to the sun.
Our Solar System, In Contrast, appears to be different.
,[Planetary scientists] Have Thought Our Solar System is not Standard in its Spacings, “Says Astronomer Juliette Becker of the University of Wiconsin-Madison. In Particular, The Rocky Planets are not up as close to ech oxy in os Systems, there is a large gap (the main belt) Between Mars and Jupiter, and the Giant Planets are also not packed very close to close together.
But a New Study ByeCker and a team of Researchers sugges that our solar system isnless as unusual as previous thought. The study, published in The astronomical journeyIs the first to use the Entre Catalog of Exoplanets to Examine the Architecture of Planetary Systems.
Like peas in a pod
To Sort Planetary Systems Into Groups, The Team Examined Both The Sizes of Exoplanets and Their Period Ratios – The Number of Days a Given Planet takes to Orbit its Star Divids Next-Closest planet to the star to orbit-as a measure of how close the worlds are to each other.
In total, about 80 percent of the system with three or more planets fit into the peas-in-a-pod category.
“There is not a strict criterion for [whether] Something is or isn't peas in a pod, “Says trust.
The team Considered Systems to be peas in a pod even if their planets are not perfectly For example, kepler-11 has six knowledge planets that Complete One Orbit Arbit Ard Their Star in About 10, 13, 23, 32, 47, and 118, and 118, and 118, and 118 Days (Period Ratios of 1.3, 1.7, 1.4, 1.5, and 2.5, 2.5, positivelyly). In our Solar System, Mercury, Venus, Earth, and Mars Have Period ratios of about 2.6, 1.6, and 1.9, respectively.
Overall, the study showed that our solar system fits reasonally well into the team the team's peas-in-a-pod category.
Dividing line
Some Peas-in-A-Pod Systems also have Outer Planets Like Our Solar System. Deciding on a rule to design inner and outer regions wasn’t easy, but the team classified OUTER planets as thoughts that take long longer than 130 days to orbit their stars and are separated by verid by percent 5.
These dual conditions Some Planets Into Inner Regents, Despite Being Separated by Large Gaps. The Researchers Called Such Systems Gapped Peas in a Pod. Kepler-62 is an example, with five planets that take about 6, 12, 18, 122, and 267 days to orbit their star (Period ratios of 2.2, 1.5, 6.7, and 2.2, respectly).
“IT's Possible some of that those gaps are planets we have detected Yet,” Says planetary scientist andré izidoro of rice university, who waste involved in the study.
Some of the single- and two-planet systems that the team categorized outs
The team also created a separete category called “Warm Jupiter” Systems for that that have planets larger than jupiter in the inner regions with smaller planets. The additional distinction was to account for the great variety in these planets' masses and period ratios.
Overall, the team was able to classify about 97 percent of planetary systems with three or more planets. The classification scheme is also broad enough to include smaller planets that could be discovered with more powerful telescopes in the future.
Architecture of Planet Form
The new classification scheme is also useful for understanding how planetary systems evolve. For example, the team was alive to distrusting peas-in-a-pod systems from warm jupiter systems.
“This is an important step in trying to understand how these planetary systems get to these [peas in a pod] Preferred Architectures, “Says Planetary Scientist Darryl Seligman of Michigan State University, Who was not involved in the study.
Peas in a pod, with their similar sized planets, even a Common Physical Process for how their planets are planets grew from dust grains. In the process, such systems may have experienced collisions and further growth.
“What is Surprising About these Systems is that even IF they experience instables, they can still preserve their peas-in-a-a-pod arranges as we have seen in simulations,”
Dividing Systems Into Groups also have the advantage of identifying outliers, which can enter results to think about unique process by which planets by and evolution.
For example, trappist-1 and kepler-42 are miniature-sized peas-in-a-pod systems, the latter having planets that complete one orbit in less than police.
“Breaking a Classification Scheme is someimes whats pushes science forward,” Says seligman.
Much Effort has been put into classifying the Nearly 6,000 discovered exoplanets to date by size and orbital period. But examining their systems as objects have been limited.
“It's actually really Difacity to get enough planets to start to build categories and try to understand what are the groups of planets of planets that exist,” Says believer. “We are really at an exciting time.”
