Browsing by Author "Tappert, Claus"
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- ItemA stellar prominence in the white dwarf/red dwarf binary QS Vir: evidence for a detached system(2011) Parsons, S.; Tappert, Claus
- ItemA tale of three cataclysmic variables with distinct superhumps(2025) Joshi, Arti; Tappert, Claus; Catelan, Márcio; Schmidtobreick, Linda; Singh, MridweekaSuperhumps are among the most commonly observed variable features in the light curves of cataclysmic variables (CVs). To study the superhump behaviour of CVs, we present Transiting Exoplanet Survey Satellite (TESS) observations of three CVs: CRTS J110014.7+131552, SDSS J093537.46+161950.8, and [PK2008] HalphaJ130559. Among them, a super-outburst has been observed in CRTS J110014.7+131552, which is associated with the precursor outburst, where prominent superhumps have been observed during maximum of the outburst with a mean period of 0.06786(1) d. We observed variations in the superhump period, along with changes in the shape of the light curve profile and the amplitude of the superhumps during different phases of the outburst, indicating disc-radius variation as well as periodically variable dissipation at the accretion stream’s bright spot. The data on SDSS J093537.46+161950.8 reveal previously unknown variations modulated with periods of 0.06584(2) d and 2.36(2) d, related to the positive superhump and the disc-precession periods, respectively, which can reasonably be interpreted as a result of the prograde precession of an eccentric accretion disc. Despite its short orbital period, the lack of outburst activity, its stable long-term brightness, discovery spectrum, and absolute magnitude suggest that the object might not be an SU UMa type dwarf nova. Instead, it could belong to the group of high-mass-transfer CVs below the period gap: either a rare class of nova-like variables or a high-luminosity intermediate polar, a subclass of magnetic CVs. For [PK2008] HalphaJ130559, a new average orbital period of 0.15092(1) d has been identified. Additionally, this system displays previously undetected average periods of 0.14517(3) d and 3.83(1) d, which could be provisionally identified as negative superhump and disc-precession periods, respectively. If the identified simultaneous signals do indeed reflect negative superhump and disc-precession period variations, then their origin might be associated with the retrograde precession of a tilted disc and its interaction with the secondary stream.
- ItemActivity on the m star of QS vir(2010) Ribeiro, T.; Tappert, Claus
- ItemCataclysmic variables from the Calan-Tololo Survey - II. Spectroscopic periods(2010) Augusteijin, T.; Tappert, Claus
- ItemEvidence for an accretion steam in the low-accretion-rate polar J2048(2010) Kafka, S.; Tappert, Claus
- ItemNSV 13983: a new dwarf nova in the period gap(2008) Contreras Peña, Carlos Eduardo; Tappert, Claus
- ItemOrbital periods of cataclysmic variables identified by the SDSS IX. NTT photometry of eight eclipsing and three magnetic systems(2015) Southworth, J.; Tappert, Claus
- ItemRR Pictoris: an old nova showing superhumps and QPOs(2008) Schmidtobreick L; Tappert, Claus
- ItemThe emission line galaxy TV Reticuli - Evidence for an ultraluminous supernova(2007) Schmidtobreick L; Tappert, Claus
- ItemThe pre-cataclysmic variable, LTT 560(2007) Tappert, Claus
- ItemThe remarkable properties of the symbiotic star AE Circinus(2008) Mennickent, R,; Tappert, Claus
- ItemVz Gru: a Blazhko-Type RR Lyr, Not a CV(2006) Tappert, Claus; Catelan, Márcio