Suleimanov V.; Kajava J.; Molkov S.; Nättilä J.; Lutovinov A.; Werner K.; Poutanen J.
(2017)
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. The ultracompact low-mass X-ray binary 4U 1820-30 situated in the globular cluster NGC 6624 has an orbital period of only ...