The light curve of the companion to PSR B1957+20

摘要

We present a new analysis of the light curve for the secondary star in the PSR B1957+20 system. Combining previous data and new data points at minimum from the Hubble Space Telescope, we have 100% coverage in the R-band. We also have a number of new Ks band data points which we use to constrain the IR magnitude of the system. We model this with the Eclipsing Light Curve code. From our best fit model we are able to constrain the system inclination to 63.9 ± 2.4° for pulsar masses ranging from 1.35 – 1.9 M. The pulsar mass is unconstrained. We also find that the secondary is not filling its Roche lobe which has important consequences for evolutionary models of this system. The temperature of the un-irradiated side of the companion is in agreement with previous estimates.