J/A+A/489/321 Period study of TW Draconis (Zejda+, 2008)
Period study of TW Draconis.
Zejda M., Mikulasek Z., Wolf M.
<Astron. Astrophys. 489, 321 (2008)>
=2008A&A...489..321Z 2008A&A...489..321Z (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Photometry
Keywords: stars: binaries: eclipsing - stars: individual: TW Dra -
stars: fundamental parameters
Abstract:
We present a study of time series data for the Algol-type eclipsing
binaries TW Draconis obtained over the past 150 years to detect
changes in minima timings. There is significant evidence for
miscellaneous interacting physical processes in the system, which
manifest themselves as for example period and light curve changes.
Using 561 available minima timings, we compile an extended O-C diagram
analysis. A detailed description of period changes allows us to
construct the true phased light curve at any moment.
The timing residuals (according to the linear ephemeris) display two
stages of differing behaviour in 1858-2007. The first part ends around
1942. It is characterized by more or less smooth linear/parabolic
course of timing residuals. In 1858-1905, the period was almost
constant P=2.806513(9)d, but, in 1905-1942, the period increased due
to mass exchange between components. Since 1942, the system has been
showing alternating and shortening period changes with the length of a
cycle of about two decades, modulated by short-term periodic
variations. The latter small variations with the period 6.5-years are
caused by the light-time effect due to the presence of a third
low-mass body in the system. Major oscillations can be explained as
consequences of quadrupole moment variation in the system.
Description:
The main table contains timings of minima of TW Draconis spanning past
150 years (1858-2008).
Objects:
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RA (2000) DE Designation(s)
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15 33 51.1 +63 54 26 TW Draconis = V* TW Dra
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 572 Timings of minima for TW Draconis
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 --- HJD Heliocentric Julian Date of Minimum
15- 16 A2 --- N [: ] Designation on the accuracy of observations
18 A1 --- Min [ps] Type of minimum (p-primary, s - secondary)
21- 29 A9 --- Type Type of observations (1)
31- 51 A21 --- Observer Name of observer(s)
53- 92 A40 --- Source Source of information Reference
94 I1 --- Note [1/2]? Note (2)
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Note (1): Type of observations ad follows:
plate = dimming on photographic plates
vis = visual observations
pg = photographic observations
pe = photoelectric measurements (used filters)
CCD = CCD measurements (used filters)
Note (2): Note as follows:
1 = new timing based on original photographic observation
2 = mean (in regard of color) timing of minimum
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Acknowledgements: Miloslav Zejda, zejda(at)physics.muni.cz
(End) M. Zejda [DTPA MU Brno, Czech Republic], P. Vannier [CDS] 18-Jul-2008