NOAO >   Observing Info >   Approved Programs >   2017A-0005

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Program Information for 2017A-0005


PI: Helen Johnston, U. of Sydney, h.johnston@sydney.edu.au
Address: SIfA, University of Sydney, Sydney, NSW 2006 Australia

CoI: Roberto Soria, Curtin University

Title: An X-ray heated companion in Cir X-1

Abstract: Cir X-1 is a highly unusual X-ray binary in an eccentric 16-day orbit. The binary is associated with a young supernova remnant, which puts a limit on the age of the system of $t < 4600$~yr. The nature of the companion star to the accreting neutron star is unknown. We have recently measured the light curve for the system, which can be modelled as coming from the heated face of the companion star. Our model suggests that the companion star is still recovering from being shock- heated by the supernova which exploded less than 5000~yr ago. We propose to obtain complete visible and infrared light curves to test this model and measure the shape of the orbit more precisely.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2017A):  CT-1.3m/ANDI -- 7.2hrs


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NOAO >   Observing Info >   Approved Programs >   2017A-0005

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