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J/A+A/497/437       V light curves of DI UMa                 (Rutkowski+, 2009)

CURious Variables Experiment (CURVE): CCD photometry of active dwarf nova DI Ursae Majoris. Rutkowski A., Olech A., Wisniewski M., Pietrukowicz P., Pala J., Poleski R. <Astron. Astrophys., 497, 437-444 (2009)> =2009A&A...497..437R
ADC_Keywords: Novae ; Binaries, cataclysmic ; Magnitudes Keywords: stars: individual: DI UMa - binaries: close - dwarf novae - novae, cataclysmic variable Abstract: We report an analysis of photometric behaviour of DI UMa, an extremely active dwarf nova. The observational campaign (completed in 2007) covers five superoutbursts and four normal outbursts. We examined principal parameters of the system to understand peculiarities of DI UMa, and other active cataclysmic variables. Based on precise photometric measurements, temporal light curve behaviour, O-C analysis, and power spectrum analysis, we investigated physical parameters of the system. We found that the period of the supercycle now equals 31.45±0.3days. Observations during superoutbursts infer that the period of superhumps equals Psh=0.055318(11)days (79.66±0.02min). During quiescence, the light curve reveals a modulation of period Porb=0.054579(6)days (78.59±0.01min), which we interpret as the orbital period of the binary system. The values obtained allowed us to determine a fractional period excess of 1.35±0.02%, which is surprisingly small compared to the usual value for dwarf novae (2%-5%). A detailed O-C analysis was performed for two superoutbursts with the most comprehensive coverage. In both cases, we detected an increase in the superhump period with a mean rate of (dP/dt)/Psh=4.4(1.0)x10-5. Based on these measurements, we confirm that DI UMa is probably a period bouncer, an old system that reached its period minimum a long time ago, has a secondary that became a degenerate brown dwarf, the entire system evolving now toward longer periods. DI UMa is an extremely interesting object because we know only one more active ER UMa star with similar characteristics (IX Dra). Description: V broad-band photometry of DI UMa was obtained with 0.5m Cassegrain telescope at Warsaw University Observatory, Ostrowik station. (table1.dat) V broad-band photometry of DI UMa collected with 0.3-m telescope amateur observatory in Slupsk. (table2.dat) The observations cover the period from January 2007 to July 2007. Objects: ------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------- 09 12 16.2 +50 53 55 DI UMa = NSV 4407 ------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 28 2798 V photometry of DI UMa with 0.5-m telescope table2.dat 28 298 V photometry of DI UMa with 0.3-m telescope
Byte-by-byte Description of file: table1.dat table2.dat
Bytes Format Units Label Explanations
1- 14 F14.6 d JD Julian Date 16- 21 F6.3 mag Vmag V magnitude 23- 28 F6.4 mag e_Vmag rms uncertainty on Vmag
Acknowledgements: Artur Rutkowski, rudy(at)camk.edu.pl
(End) Patricia Vannier [CDS] 14-May-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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