Astronomers divide planetary systems into four flavors – 03/12/2023 – Sidereal Messenger

Is the Solar System common or atypical? As our statistics on planetary systems increase, researchers can begin to tackle questions like this one, as well as understand what gives rise to the enormous variety of configurations that a family of planets can assume around a star. A quartet of researchers now argue that they can be grouped into four basic categories.

In an article published in the journal Astronomy & Astrophysics, Lokesh Mishra, Tann Alibert and Christoph Mordasini of the University of Bern, and Stéphane Udry of the University of Geneva, suggest that systems of planets can come in similar, ordered, mixed and anti-ordered flavors. But what does that mean? Well, in essence, it depends on the parameter you want to study. The researchers concentrated in that first moment on the masses.

A similar category system is one in which all the planets are of similar mass. Ordered are those that, like ours, show a general tendency to increase in mass, from the innermost planet to the outermost. An antiorder would be the opposite: planets with more mass on the inside, and those with less on the outer regions. And the mixed would be one where the mass fluctuates significantly from planet to planet, with no specific overall trend.

To explore the usefulness of this discrimination procedure, the group applied its categories to two catalogues, one of 41 real systems, with four or more planets of which at least four of them had the estimated mass, and another of virtual systems, a thousand of them, ” gestados” in computer simulations. The idea was to compare what is seen in the real world (incomplete due to observation limitations) with simulations (complete, but inaccurate, given the simplification of processes).

Indeed, there was a contrast between the two results. In real systems, the majority (59%) belonged to the similar class. Ordered systems (such as Solar, included in the catalog) accounted for 37%. Another 5% had mixed architecture. And none of them are anti-ordained.

In the thousand simulated systems, varying initial parameters such as the mass of the formation disk and the amount of heavy elements (following what happens in reality), the numbers were different. Again, the similar category came out on top, but with 80.2%. About 8% of virtual systems ended up with mixed or anti-order architectures. And only 1.5% ended up like the Solar System, with orderly architecture.

Because both have inaccuracies, none of these percentages should accurately reflect reality. However, they reveal trends that are probably true. For example, the fact that most systems tend to have planets of similar mass, something that had already been noticed.

In this context, the Solar System can be something of a rarity, although others like it appear more frequently in observations, perhaps due to a bias: they are a much easier type to detect than the antiorder.

This column is published on Mondays in the printed version, in Folha Corrida.

Follow the Sidereal Messenger on Facebook, twitterInstagram and YouTube

PRESENT LINK: Did you like this text? Subscriber can release five free hits of any link per day. Just click the blue F below.