J/A+A/691/A112 TT Ari frequency groups (Vega-Manubens+, 2024)
TT Arietis: New approach in the analysis of quasi periodic oscillations.
Vega-Manubens I., Vogt N., Lopera-Mejia A., Aravena-Rojas G.,
Rojas Lobos P.A.
<Astron. Astrophys. 691, A112 (2024)>
=2024A&A...691A.112V 2024A&A...691A.112V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, white dwarf ; Binaries, cataclysmic ; Asteroseismology
Keywords: methods: data analysis - stars: dwarf novae - novae -
cataclysmic variables - stars: individual: TT Arietis
Abstract:
TT Arietis (TT Ari) is a nova-like cataclysmic variable of the VY Scl
subtype, with light curve variations on multiple timescales. Besides
the superhump modulation, quasi-periodic oscillations (QPOs) have been
found.
The aim is to determine the occurrence, strength and variability of
QPOs in TT Ari, based on more complete data than in previous works.
The data were obtained during the high state of TT Ari in October 2012
by the MOST space telescope, covering a total of 361.2 hours of
continuous observation. We searched for frequencies over subsets of
time using a Fourier-like power spectrum and then added the
frequencies together forming groups.
Our method has revealed QPOs that occur in 'frequency groups', which
are events with a continuous oscillation of similar, constant or
slowly variable frequency. We report a total of 160 frequency groups
in the period range between 14 and 53 minutes (27 and 98 days-1),
with two peaks in the power spectrum at 18.5 and 33.8 minutes (42.5
and 77.5 days-1). The duration of these frequency groups varies
between 0.72 and 7.5 hours (average 2.8 hours) revealing between 3 and
18 complete cycles in the light curve. Most of them show significant
frequency variations over the course of their duration. Sometimes two
frequency groups occur simultaneously. An analysis with randomised
data confirms that stochastic processes can only explain a fraction of
the QPOs found. The occurrence of QPOs appears not to be related to
the superhump phase.
Description:
Our method has revealed QPOs, occurring in "frequency groups", which
are events with a continuous oscillation of similar, constant or
slowly variable frequency. We report a total of 160 frequency groups
in the period range between 14 and 53 minutes (27 and 98 days-1),
with two peaks in the power spectrum at 18.5 and 33.8 minutes (42.5
and 77.5 days-1). The duration of these frequency groups varies
between 0.72 and 7.5 hours (average 2.8 hours) revealing between 3 and
18 complete cycles in the light curve. Most of them show significant
frequency variations over the course of their duration. Sometimes two
frequency groups occur simultaneously. An analysis with randomised
data confirms that stochastic processes could only explain a fraction
of the QPOs found. The occurrence of QPOs appears not to be related to
the superhump phase.
Objects:
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RA (2000) DE Designation(s)
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02 06 53.07 +15 17 41.8 TT Ari = BD+14 341
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 51 160 Information of groups from a normal filter
tablea2.dat 51 80 Information of groups from a strict filter
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See also:
J/A+A/265/77 : VBLUW Observations of TT Ari (Hollander+ 1992)
J/A+A/496/765 : R light-curve of TT Ari (Kim+, 2009)
Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 10 F10.2 d JD Starting date of each group
12- 17 F6.2 d-1 Fmean Mean frequency of each group
19- 22 F4.2 d Dur Duration of each group
24- 28 F5.3 --- Pmean Mean power of each group in the power spectrum
30- 34 F5.1 d-1 deltaF Frequency delta (difference between the
last and first frequency in each group)
36- 39 F4.1 d-1 AmpF Frequency amplitude (difference between the
highest and lowest frequency in each group)
41- 44 F4.1 --- Nc Number of completed cycles of each group
46- 51 F6.4 --- Phase Phase of the superhump maximum
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Acknowledgements:
Ignacio Vega-Manubens, ignacio.vega(at)postgrado.uv.cl
(End) Patricia Vannier [CDS] 24-Sep-2024