Carnegie: Twin Stars Hosting Three Giant Exoplanets

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Carnegie: Twin Stars Hosting Three Giant Exoplanets

Post by bystander » Wed Aug 31, 2016 2:50 pm

Discovery One-Ups Tatooine, Finds Twin Stars Hosting Three Giant Exoplanets
Carnegie Institution for Science | 2016 Aug 31
[img3="An illustration of this highly unusual system, which features the smallest-separation binary stars that both host planets ever discovered. Only six other metal-poor binary star systems with exoplanets have ever been found. Courtesy: Timothy Rodigas"]https://carnegiescience.edu/sites/carne ... 50x712.jpg[/img3][hr][/hr]
A team of Carnegie scientists has discovered three giant planets in a binary star system composed of stellar ''twins'' that are also effectively siblings of our Sun. One star hosts two planets and the other hosts the third. The system represents the smallest-separation binary in which both stars host planets that has ever been observed. The findings, which may help explain the influence that giant planets like Jupiter have over a solar system’s architecture, have been accepted for publication in The Astronomical Journal.

New discoveries coming from the study of exoplanetary systems will show us where on the continuum of ordinary to unique our own Solar System’s layout falls. So far, planet hunters have revealed populations of planets that are very different from what we see in our Solar System. The most-common exoplanets detected are so-called super-Earths, which are larger than our planet but smaller than Neptune or Uranus. Given current statistics, Jupiter-sized planets seem fairly rare—having been detected only around a small percentage of stars.

This is of interest because Jupiter’s gravitational pull was likely a huge influence on our Solar System’s architecture during its formative period. So the scarcity of Jupiter-like planets could explain why our home system is different from all the others found to date.

The new discovery from the Carnegie team is the first exoplanet detection made based solely on data from the Planet Finding Spectrograph—developed by Carnegie scientists and mounted on the Magellan Clay Telescopes at Carnegie’s Las Campanas Observatory. PFS is able to find large planets with long-duration orbits or orbits that are very elliptical rather than circular, including the new trio of planets discovered in this `”twin’” star study. This special capability comes from the long observing baseline of PFS; it has been taking observations for six years. ...

The Magellan PFS Planet Search Program: Radial Velocity and Stellar Abundance
Analyses of the 360 AU, Metal-Poor Binary "Twins" HD 133131A & B
- Johanna K. Teske et al
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