Abstract:

We present new X-ray and optical spectra of the old nova CP Pup (nova Pup 1942) obtained with Chandra and the Cerro Tololo Inter American Observatory (CTIO) 4 m telescope. The X-ray spectrum reveals a multitemperature optically thin plasma reaching a maximum temperature of 36^{+19}_{-16} keV absorbed by local complex neutral material. The time-resolved optical spectroscopy confirms the presence of the ?1.47 h period, with cycle-to-cycle amplitude changes, as well as of an additional long-term modulation which is suggestive either of a longer period or of non-Keplerian velocities in the emission line regions. These new observational facts add further support to CP Pup as a magnetic cataclysmic variable (mCV). We compare the mCV and the non-mCV scenarios and, while we cannot conclude whether CP Pup is a long-period system, all pieces of observational evidence point at an intermediate polar-type CV.

Author affiliation: Mason, E.. Osservatorio Astronomico di Trieste; Italia; Space Telescope Science Institute, Estados Unidos de América;

Author affiliation: Orio, M.. Osservatorio Astronomico di Padova; Italia;

Author affiliation: Mukai, K.. NASA Goddard Space Flight Center; Estados Unidos de América;

Author affiliation: Bianchini, A.. Dipartimento di Astronomia; Italia;

Author affiliation: de Martino, D.. Osservatorio Astronomico di Capodimonte, Italia;

Author affiliation: Di Mille, F.. Australian Astronomical Observatory-Carnegie Observatories, Colina; Chile; Dipartimento di Astronomia; Italia;

Author affiliation: Williams, R. E.. Department of Astronomy, University of Wisconsin, Estados Unidos de América;

Author affiliation: Abbot, T..

Author affiliation: de Propris, R..

Author affiliation: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa, Ciudad Universitaria. Instituto de Astronomía y Física del Espacio (i);