Tut Campbell

THE 2001 SUPEROUTBURST OF WZ SAGITTAE

ABSTRACT We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

BK Lyncis: the oldest old nova?... and a Bellwether for cataclysmic variable evolution

V=15.5

Rapid Oscillations in Cataclysmic Variables. XVII. 1RXS J070407 + 262501

\end{document} , the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ∼1 mag amplitude and 2 day recurrence time; these “echo outbursts” are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 ...

Accretion-disc precession in UX Ursae Majoris

We summarize the results of a 20-year campaign to study the light curves of BK Lyn, a nova-like star strangely located below the 2-3 hour orbital-period gap in the family of cataclysmic variables (CVs). Two apparent superhumps dominate the nightly light curves with periods 4.6% longer, and 3.0% shorter, than the orbital period. The first appears to be associated with the star’s brighter states (V � 14), while the second appears to be present throughout and becomes very dominant in the low state (V � 15.7). It is plausible that these arise, respectively, from a prograde apsidal precession and a retrograde nodal precession of the star’s accretion disk.

ORBIT-RESOLVED PHOTOMETRY AND ECHELLE SPECTROSCOPY OF THE CATACLYSMIC VARIABLE ST LMi DURING A 2007 HIGH STATE

We present a study of the recently discovered intermediate polar 1RXS J070407 + 262501, distinctive for its large-amplitude pulsed signal at P = 480 s. Radial velocities indicate an orbital period of 0.1821(2) days, and the light curves suggest 0.18208(6) days. Time-series photometry shows a precise spin period of 480.6700(4) s, decreasing at a rate of 0.096(9) ms yr-1: i.e., on a time scale =2.5×106 yr. The light curves also appear to show a mysterious signal at P = 0.263 days, which could possibly signify the presence of a superhump in this magnetic cataclysmic variable.

Superhumps and spin-period variations in the intermediate polar RX J2133.7+5107

We thank the National Science Foundation for support of this re search (AST12-11129), and also the Mount Cuba Astronomical Foundation. Finally, we thank the American Association of Variable Star Obs ervers (AAVSO) for providing the infrast ructure and continued inspirat ion which makes programs like this possible.

IGR J19552+0044: A new asynchronous short period polar: Filling the gap between intermediate and ordinary polars⋆

We present high-resolution echelle spectra and contemporaneous photometry of the polar ST LMi during a high state in 2007 March. Emission lines at Hα, He I λ5876, and He I λ7065 show similar line profiles over orbital phase and have narrow and broad components. These profile changes with phase are very similar to those reported in earlier high-state studies of ST LMi. The radial velocity curves from double Gaussian fits to the line profiles are interpreted as two crossing curves, neither of which is coincident with the orbital motion of the secondary star. We attribute one component to infall motions near the white dwarf and the other to a gas streaming along magnetic field lines connecting the two stars.

RAPID OSCILLATIONS IN CATACLYSMIC VARIABLES XVI. DW CANCRI

We thank the National Science Foundation for support of this research (AST-1211129 and AST-1615456), and NASA through HST-G0-13630. EdM acknowledges financial support from the Ministerio de Educacion, Cultura y Deporte (Spain) under the Mobility Program Salvador de Madariaga (PRX15/00521).

The orbital period of the eclipsing dwarf nova SDSS J081610.84+453010.2

Based on XMM--Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar. We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this X-ray source correctly. Extensive multicolor photometric and medium- to high-resolution spectroscopy observations were performed and period search codes were applied to sort out the complex variability of the object. We found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric (83.599+/-0.002m) periods that we ascribe to the white dwarf (WD)\ spin period and binary orbital period, respectively. This confirms that IGR J19552+0044 is an asynchronous polar. Wavelength-dependent variability and its continuously changing shape point at a cyclotron emission from a magnetic WD with a relatively low magnetic field below 20 MG. The difference between the WD spin period and the binary orbital period proves that IGR J19552+0044 is a polar with the largest known degree of asynchronism (0.97 or 3%).