Cataclysmic Variables and Their Behavior
Explore the fascinating world of cataclysmic variables, binary systems featuring a white dwarf accreting from a companion star. Delve into regular outbursts, state changes, and non-orbital photometric variations in these unique celestial phenomena. Witness the complexities of these systems through a variety of observations and data.
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Presentation Transcript
Cataclysmic variables that splutter Keith Inight Warwick University 1
Cataclysmic Variables (CVs) Close binary systems where a white dwarf is accreting from a companion star that is filling its Roche lobe. Non-magnetic Magnetic Source: Wikipaedia 3
Dwarf Nova Regular outbursts 4
Novalike State change
Magnetic (polar) State change
Non-orbital photometric variations Amplitude ( m) Non- Magnetic Novae Superoutbursts Duration Recurrence References Dwarf Outbursts 3-5 A few days Days to decades Osaki, Y (1974) 3-9 A few weeks Months to decades Years Buat-M nard, V et al (2002) Dhillon, V.S. (1996) Novalikes State changes Several Months to Years Stunted outbursts 0.14-1.35 5-50 days Months Honeycutt, R. K. et al (2025) Simonsen, M. et al (2014) Kafka,S & Honeycutt,R.K. (2005) Bruch, A (2021) Z Cam Standstills 0.5-4 Tens of days to years Months Years Magnetic Polars State changes 1-5 Years All Flickering <0.25 Minutes Minutes
IR Com light curve from ZTF Magnitude Manser, C. J. and Gansicke, B. T. (2014) MJD-50000 9
IR Com is not alone Sloan Digital Sky Survey 10
IR Com is not alone A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities. Inight et al (2023) Magnitude Discovered from spectroscopy not transients 8 out of 507 implies ~1.6% 11
DESI Magnitude Inight et al in prep 7 out of 750 implies ~1% MJD-50000
What is going on? Spectroscopy confirms that these CVs have disks; the absence of outbursts indicates a low ? No evidence of magnetism in the WD (such as He II emission, x-ray bright.., WD spin detected) Periods vary from 1.7-6h indicating widely varying evolutionary stages So the assumption is that the cause is changes in the mass loss rate from the donor Speculation Some sort of changes in the magnetic field of the donor possibly resulting in starspots (cf Kafka,S & Honeycutt,R.K. (2005))? 13
Questions? 14
