Weak enhancement in the optical activity of HDE245770/A0535+26 system
ATel #8446; F. Giovannelli (INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy)), I. Bruni (INAF-Osservatorio Astronomico di Bologna, Stazione Astronomica diLoiano, Italy), G. S. Bisnovatyi-Kogan (IKI â Space Research Institute, Moscow, Russia), J. Salas Procas (AgrupacionAstronomica de Huesca, Spain), C. Rossi (Dpt of Physics, La Sapienza University, Roma, Italy, F. Martinelli & M. Monaci (Lajatico Astronomical Centre, Italy)
on 21 Dec 2015; 14:07 UT
Credential Certification: Corinne Rossi (corinne.rossi@uniroma1.it)
Subjects: Optical, X-ray, Binary, Neutron Star, Pulsar
Referred to by ATel #: 8487
We continued the monitoring of HDE 245770 in V band around the periastron passage of the neutron star A0535+26 (JD 2457376) following the ephemeris of Giovannelli et al.: 2013, A&A, 560, A1G [JD_opt-out = JD_0(2444944) +- n(111.0 +- 0.4) days].
This passage is just 112 orbital periods after the 811205-E.
The luminosity in V band showed an enhancement, reaching about 0.02 mag at JD 2457375.679.
This is an indication that the X-ray pulsar is close to experience an X-ray outburst within about 8 days with an expected intensity of about 20-80 mCrab, in accordance with Giovannelli et al.(2015, Acta Astronomica, Vol. 65, 107â116).
Coordinated optical and X-ray measurements are strongly required.
