Survey of period variations of superhumps in SU UMa-type dwarf novae. V. The fifth year (2012–2013)

Abstract

Continuing the project described in Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for SU UMa-type dwarf novae mainly observed during the 2012-2013 season. We found three objects (V444 Peg, CSS J203937, and MASTER J212624) having strongly positive period derivatives despite the long orbital period (P orb ). By using the period of growing stage (stage A) superhumps, we obtained mass ratios for six objects. We characterized nine new WZ Sge-type dwarf novae. We made a pilot survey of the decline rate in the slowly fading parts of SU UMa-type and WZ Sge-type outbursts. The decline time scale was found to generally follow an expected P 1/4 orb dependence, and WZ Sge-type outbursts also generally follow this trend. There are some objects which show slower decline rates, and we consider these objects good candidates for period bouncers. We also studied unusual behavior in some objects, including BK Lyn which made a transition from an ER UMa-type state to a novalike (standstill) state in 2013, and unusually frequent occurrences of superoutbursts in NY Ser and CR Boo. We applied the least absolute shrinkage and selection operator (Lasso) power spectral analysis, which has been proven to be very effective in analyzing the Kepler data, to the ground-based photometry of BK Lyn, and detected a dramatic disappearance of the signal of negative superhumps in 2013. We suggested that the mass-transfer rates did not strongly vary between the ER UMa-type state and novalike state in BK Lyn, and this transition was less likely caused by a systematic variation of the mass-transfer rate.

The evolutionary status of Cataclysmic Variables: eclipse modelling of 15 systems

“…Savoury et al 2011), new potential calibration systems have emerged, in addition to revised q values for existing calibration systems. Revised superhump periods have also been measured, courtesy of the SU UMa-type DNe survey of Kato et al (2009Kato et al ( , 2010Kato et al ( , 2012Kato et al ( , 2013Kato et al ( , 2014aKato et al ( ,b, 2015Kato et al ( , 2016Kato et al ( , 2017. With all of these new measurements becoming available since the work of Knigge (2006), it is appropriate to update the calibration of the (q) relation.…”

“…Given our updating of the superhump-mass ratio relations above, we revisit the analysis of donor star properties in Knigge (2006) and Knigge et al (2011). Firstly, P sh values for all SU UMa-type DNe in the Patterson et al (2005) sample (70 systems) were replaced by P B sh measurements from the SU UMa-type DNe survey of Kato et al (2009Kato et al ( , 2010Kato et al ( , 2012Kato et al ( , 2013Kato et al ( , 2014aKato et al ( ,b, 2015Kato et al ( , 2016Kato et al ( , 2017. For a number of systems, P orb was also updated, either from measurements made by Tables 2 and B1 Patterson et al (2005).…”

Transient emission of selected CRTS Cataclysmic Variables

“…A peculiar narrow emission line within the double-peaked Hα line was also observed, which is ascribed to chromospheric emission from the irradiated inner hemisphere of the donor. Kato et al (e.g [36] and [37]) observed superoutbursts in 2012 and 2013. To date no normal outbursts have been observed for this source.…”

The ASAS-SN Bright Supernova Catalog -- IV. 2017

“…ASAS-SN is designed to survey the entire visible sky at a rapid cadence to find the brightest transients. ASAS-SN has found many nearby and interesting SNe (e.g., Dong et al 2016;Holoien et al 2016a;Shappee et al 2016;Godoy-Rivera et al 2017;Bose et al 2018b,a;Vallely et al 2019), tidal disruption events (TDEs; e.g., Holoien et al 2014a;Brown et al 2016Brown et al , 2017aHoloien et al 2016c,b;Prieto et al 2016;Romero-Cañizales et al 2016;Holoien et al 2018), stellar outbursts (Holoien et al 2014b;Schmidt et al 2014;Herczeg et al 2016;Schmidt et al 2016), flares from active galactic nuclei (Shappee et al 2014), black hole binaries (Tucker et al 2018), and cataclysmic variable stars (Kato et al 2014a(Kato et al ,b, 2015(Kato et al , 2016.…”