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 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:
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RA (2000) DE Designation(s)
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09 12 16.2 +50 53 55 DI UMa = NSV 4407
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File Summary:
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FileName Lrecl Records Explanations
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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
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Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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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
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Acknowledgements:
Artur Rutkowski, rudy(at)camk.edu.pl
(End) Patricia Vannier [CDS] 14-May-2009