Peculiar planetary system architecture around three Orion stars
explained

Date:
September 3, 2020
Source:
Carnegie Institution for Science
Summary:
In our Solar System, the eight planets and many other minor objects
orbit in a flat plane around the Sun; but in some distant systems,
planets orbit on an incline -- sometimes a very steep one. New
work could explain the architecture of multi-star systems in which
planets are separated by wide gaps and do not orbit on the same
plane as their host star's equatorial center.



FULL STORY ==========================================================================
The discovery that our galaxy is teeming with exoplanets has also
revealed the vast diversity of planetary systems out there and raised
questions about the processes that shaped them. New work published in
Science by an international team including Carnegie's Jaehan Bae could
explain the architecture of multi- star systems in which planets are
separated by wide gaps and do not orbit on the same plane as their host
star's equatorial center.


==========================================================================
"In our Solar System, the eight planets and many other minor objects
orbit in a flat plane around the Sun; but in some distant systems,
planets orbit on an incline -- sometimes a very steep one," Bae
explained. "Understanding the origins of extremely oblique orbital angles
such as these could help reveal details about the planetary formation
process." Stars are born in nurseries of gas and dust called molecular
clouds -- often forming in small groups of two or three. These young
stars are surrounded by rotating disks of leftover material, which
accretes to form baby planets. The disk's structure will determine
the distribution of the planets that form from it, but much about this
process remains unknown.

Led by University of Exeter's Stefan Kraus, the team found the first
direct evidence confirming the theoretical prediction that gravitational interactions between the members of multi-star systems can warp or break
their disks, resulting in misaligned rings surrounding the stellar hosts.

Over a period of 11 years, the researchers made observations of the
the GW Orionis triple-star system, located just over 1,300 light-years
away in the Orion constellation. Their work was accomplished using the
European Southern Observatory's Very Large Telescope and the Atacama
Large Millimeter/ submillimeter Array -- a radio telescope made up of
66 antennas.

"Our images reveal an extreme case where the disk is not flat at all,
but is warped and has a misaligned ring that has broken away from the
disk," Kraus said.

Their findings were tested by simulations, which demonstrated that the
observed disorder in the orbits of the three stars could have caused
the disk to fracture into the distinct rings.

"We predict that many planets on oblique, wide-separation orbits will be discovered in future planet imaging campaigns," said co-author Alexander Kreplin, also of the University of Exeter.

Bae concluded: "This system is a great example of how theory and observing
can inform each other. I'm excited to see what we learn about this system
and others like it with additional study." Support for this research was provided by the European Research Council under the European Commission's Horizon 2020 program Seventh Framework program; the Science Technology
and Facilities Council; the U.S. NSF; NASA; the research council of the
KU Leuven; and the Space Telescope Science Institute, which is operated
by the Association of Universities for Research in Astronomy.


========================================================================== Story Source: Materials provided by
Carnegie_Institution_for_Science. Note: Content may be edited for style
and length.


========================================================================== Related Multimedia:
* Images_and_illustration_of_GW_Orionis ========================================================================== Journal Reference:
1. Stefan Kraus, Alexander Kreplin, Alison K. Young, Matthew R. Bate,
John
D. Monnier, Tim J. Harries, Henning Avenhaus, Jacques Kluska,
Anna S. E.

Laws, Evan A. Rich, Matthew Willson, Alicia N. Aarnio, Fred
C. Adams, Sean M. Andrews, Narsireddy Anugu, Jaehan Bae, Theo
Ten Brummelaar, Nuria Calvet, Michel Cure', Claire L. Davies,
Jacob Ennis, Catherine Espaillat, Tyler Gardner, Lee Hartmann,
Sasha Hinkley, Aaron Labdon, Cyprien Lanthermann, Jean-Baptiste
Lebouquin, Gail H. Schaefer, Benjamin R.

Setterholm, David Wilner, Zhaohuan Zhu. A triple-star system
with a misaligned and warped circumstellar disk shaped by disk
tearing. Science, 2020 DOI: 10.1126/science.aba4633 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200903145028.htm

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