Discovery of alien world with strange, tilted orbit puzzles astronomers

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The 3D modeling of a planet's orbit around a star in a binary star system is raising new questions about how both gas giant planets and binary stars form.

Discovery of alien world with strange, tilted orbit puzzles astronomers : Read more

 

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The article points out, "One problem in forming such a system is that gas giants are thought to take 5 to 10 million years to accrete all their gas from the planet-forming disk around them. However, the current models suggest that such a disk in a binary system survives for less than 1 million years before gravitational tides from the companion star break the disk apart. Furthermore, in the case of GJ 896AB, the two stars are red dwarfs, which makes the existence of a gas giant planet in the system even more surprising. Scientists think red dwarfs lack the necessary amount of raw material to form giant planets, but the presence of a gas giant in this binary system suggests that planets could form differently when there are two stars present. "Additional detailed studies of this and similar systems can help us gain important insights into how planets are formed in binary systems," Sanchez-Bermudez said."

I read about this system at phys.org. First full 3D view of binary star-planet system from VLBA, https://phys.org/news/2022-09-full-3d-view-binary-star-planet.html

My observation. The phys.org report calls attention to how difficult it is to explain the origin of this exoplanet around the binary star system using the protoplanetary disc model. "In particular, current models indicate that such a large planet is very unlikely as a companion to such a small star, so maybe those models need to be adjusted," he added. The astrometric technique will be a valuable tool for characterizing more planetary systems, the astronomers said.”

Ref - 3D Orbital Architecture of a Dwarf Binary System and Its Planetary Companion, https://iopscience.iop.org/article/10.3847/1538-3881/ac7c66, 01-Sep-2022. “Abstract Because of the diversity of stellar masses and orbital sizes of binary systems and the complex interaction between star–star, star–planet, and planet–planet, it has been difficult to fully characterize the planetary systems associated with binary systems. Here, we report high-precision astrometric observations of the low-mass binary system GJ 896AB, revealing the presence of a Jupiter-like planetary companion (GJ 896Ab). The planetary companion is associated to the main star GJ 896A, with an estimated mass of 2.3 Jupiter masses and an orbit period of 284.4 days..."

The Extrasolar Planet Encyclopaedia — GJ 896A b (exoplanet.eu), the value for e is large too, 0.35.

 

[rod]

Here is another example of exoplanet reports indicating problems with the model explaining their origin.

Planetary heist: Astronomers show massive stars can steal Jupiter-sized planets, https://phys.org/news/2022-09-planetary-heist-astronomers-massive-stars.html

“Jupiter-sized planets can be stolen or captured by massive stars in the densely populated stellar nurseries where most stars are born, a new study has found. Researchers from the University of Sheffield have proposed a novel explanation for the recently discovered B-star Exoplanet Abundance STudy (BEAST) planets. These are Jupiter-like planets at large distances (hundreds of times the distance between the Earth and the sun) from massive stars. Until now their formation has been something of a mystery, as massive stars emit large amounts of ultraviolet radiation that stops planets from growing to the size of Jupiter—the largest planet in our solar system."

My observation. Wikipedia reports Sco Cen OB association about 130 pc or 420 LY distance, https://en.wikipedia.org/wiki/Scorpius–Centaurus_association, the two exoplanets mentioned in the report I did not see identified. At the exoplanet.eu site I found 21 large exoplanets using semi-major axis between 290 au and 600 au. Using the NASA exoplanet archive site and same selection criteria, I found 8 listed.

Ref - Making BEASTies: dynamical formation of planetary systems around massive stars, https://academic.oup.com/mnrasl/art...1/6691413?redirectedFrom=fulltext&login=false, 07-Sep-2022. "ABSTRACT Exoplanets display incredible diversity, from planetary system architectures around Sun-like stars that are very different from our Solar system, to planets orbiting post-main-sequence stars or stellar remnants. Recently, the B-star Exoplanet Abundance STudy (BEAST) reported the discovery of at least two super-Jovian planets orbiting massive stars in the Sco Cen OB association."

Planet building looks like a violent, catastrophic series of events and looking at the mass of exoplanets reported today in the area of 3 au or closer, comparing to our solar system mass and configuration is intriguing and interesting when it comes to origin science.