Artist's impression of the 5km diameter central core of Square Kilometre Array (SKA) antennas - a lot of white dishes going off to the horizon on a dry landscape. Made by SPDO/TDP/DRAO/Swinburne Astronomy Productions and placed on Wikicommons with a Creative Commons copyright: https://commons.wikimedia.org/wiki/File:SKA_overview.jpg

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   John Carlos Baez (johncarlosbaez@mathstodon.xyz)'s status on Wednesday, 20-Nov-2024 03:51:22 JST John Carlos Baez

   in reply to

   For more on this particular black widow pulsar, see:

   https://en.wikipedia.org/wiki/PSR_J1311%E2%80%933430

   About 41 black widow pulsars have been found: these are pulsars with a companion less than 1/10 the mass of our Sun. A smaller number of redback pulsars have been found: these have a companion with mass between 1/10 and 7/10 that of our Sun. If the companion's mass is even bigger, we get a 'huntsman'.

   The Square Kilometer Array is a huge radio telescope array planned in Australia and South Africa. It should help us many more of these exotic binary stars. That will help us understand if redbacks turn into black widows as the companion gradually loses mass.

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