From EarthSky: “How do planets form after star death?”



Astronomers studied the Geminga pulsar (inside the black circle), seen here moving towards the upper left. The orange dashed arc and cylinder show a ‘bow-wave’ and a ‘wake’ which might be key to after-death planet formation. The region shown is 1.3 light-years across. Image via Jane Greaves / JCMT / EAO/ RAS.

The Royal Astronomical Society’s National Astronomy Meeting is going on this week (July 2-6, 2017) in Yorkshire, England. One interesting presentation comes from astronomers Jane Greaves and Wayne Holland, who believe they’ve found an answer to the 25-year-old mystery of how planets form around neutron stars, essentially dead stars left behind by supernova explosions. These astronomers studied the Geminga pulsar, thought to be a neutron star left by a supernova some 300,000 years ago. This object is known to be moving incredibly fast through our galaxy, and the astronomers have observed a bow-wave, shown in the image above, that might be crucial to forming after-death planets.

They looked at the extreme environment around a neutron star – the sort of star we typically observe as a pulsar – a super-dense star remnant, left behind by a supernova.

The first-ever confirmed detection of extrasolar planets – or planets orbiting distant suns – came in 1992, when astronomers found several terrestrial-mass planets orbiting the pulsar PSR B1257+12. Since then they’ve learned that planets orbiting neutron stars are incredibly rare; at least, few have been found.

The two scientists observed Geminga using the James Clerk Maxwell Telescope (JCMT) near the summit of Mauna Kea in Hawaii.

East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA

The light the astronomers detected has a wavelength of about half a millimeter, is invisible to the human eye, and struggles to get through the Earth’s atmosphere. They used a special camera system called SCUBA and said:

What we saw was very faint. To be sure, we went back to it in 2013 with the new camera our Edinburgh-based team had built, SCUBA-2, which we also put on JCMT. Combining the two sets of data helped to ensure we weren’t just seeing some faint artifacts.

If ALMA data confirm their new model for Geminga, the team hopes to explore some similar pulsar systems, and contribute to testing ideas of planet formation by seeing it happen in exotic environments. Their statement said:

This will add weight to the idea that planet birth is commonplace in the universe.

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

See the full article here .

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