Detalles de publicación
PP 025085
The orbital period and inclination of the neutron star X-ray transient MAXI J1807+132
(1) Instituto de Astrofísica de Canarias (IAC), Vía Láctea, La Laguna, E-38205, Santa Cruz de Tenerife, Spain
(2) Departamento de Astrofísica, Universidad de La Laguna, E-38206, Santa Cruz de Tenerife, Spain
(3) New York University Abu Dhabi, PO Box 129188, Abu Dhabi, UAE
(4) Center for Astrophysics and Space Science (CASS), New York University Abu Dhabi, PO Box 129188, Abu Dhabi, UAE
The neutron star X-ray transient MAXI J1807+132 has undergone outbursts in 2017, 2019, and 2023. We conducted an R-band time series photometry campaign using the Isaac Newton Telescope during the 2022 quiescent state. We detected a periodic variation in the light curve, consistent with ellipsoidal modulation, which allowed us to determine an orbital period of Porb = 4.258 ± 0.008 hr. By modelling the light curve, we obtained a binary inclination of i = 72 ± 5 deg and a mass ratio q = 0.24^{+0.19}_{−0.14} (68 per cent confidence level). Furthermore, our analysis supports an early M-dwarf companion that contributes between 30 and 50 per cent to the total flux in the R-band. We extend the previously established absolute magnitude versus orbital period correlation for black hole X-ray transients to neutron star systems. We applied the correlation to MAXI J1807+132, estimating its distance as 6.3 ± 0.7 kpc and its height above the Galactic plane to be 1.6 ± 0.2 kpc.