J/AJ/144/50 Light curves of AV Hya and DZ Cas (Yang+, 2012)
Photometric properties for selected Algol-type binaries.
IV. AV Hydrae and DZ Cassiopeiae.
Yang Y.-G., Li L.-H., Dai H.-F.
<Astron. J., 144, 50 (2012)>
=2012AJ....144...50Y 2012AJ....144...50Y
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI
Keywords: binaries: close - binaries: eclipsing -
stars: individual (AV Hydrae, DZ Cassiopeiae)
Abstract:
We present BVR photometric observations and several eclipsing times
for AV Hya and DZ Cas from 2004 to 2011. Using the Wilson-Devinney
method, the photometric solutions with hot spots were deduced from
their asymmetric light curves. The results indicate that both stars
are Algol-type binaries, whose mass ratio, qph, and fill-out factor
of the primary, f1, are qph=0.255(±0.002) and f1=81.2(±0.2)%
for AV Hya, and qph=0.093(±0.003) and f1=98.7(±0.3)% for DZ
Cas. Based on all available light minimum times, it is discovered that
the O-C curve of each star could be described by a light-time orbit
overlying on a downward parabola. Their periods and amplitudes are
P3=37.2(±0.7)yr and A=0.0095'(±0.0006') for AV Hya, and
P3=62.5(±1.0)yr and A=0.0183'(±0.0007') for DZ Cas. Cyclic
variations may result from the light-time effect due to the third
body. The secular period decrease rates are
dP/dt=-1.47(±0.04)x10-7days/yr for AV Hya and
dP/dt=-0.92(±0.04)x10-7days/yr for DZ Cas. This may be interpreted
using mass and angular momentum loss from the system. With decreasing
period, the fill-out factor of the primary increases and it may
finally fill its inner Roche lobe. Therefore, AV Hya and DZ Cas with a
secular period decrease will evolve from semi-detached configurations
into contact ones.
Description:
BVR photometry of AV Hya and DZ Cas was acquired with the 60cm
telescope at the Xinglong stations (XLs) of the National Astronomical
Observatories of China (NAOC). The standard Johnson-Cousins UBVRI
filters were used.
Photometric observations of AV Hya were obtained on 2009 January 1, 6,
and 9. another two eclipsing times of AV Hya were observed on 2008
December 17 and 2011 September 5 using the 85cm telescope at the
Xinglong station of NAOC.
DZ Cas was observed from 2011 September 29 to October 2. Additionally,
two eclipsing times of DZ Cas were obtained on 2004 December 4 and 6
using the 1.0m telescope of the Yunnan Astronomical Observatory
(YNAO), and on 2009 November 4 with the 1.0m telescope at the Weihai
observatory (WHO) of Shandong University in China.
For AV Hya, we collected a total of 130 light minimum times which
cover the time span 1944-2011 (Table 3). For DZ Cas, the 93 collected
eclipsing times come from 1934 up to 2012, with a long gap between
1981 and 1990.
Objects:
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RA (2000) DE Designation(s) (Period)
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09 35 02.55 +05 19 24.0 AV HYDRAE = AN 350.1934 (P=0.68340432)
23 39 49.94 +55 52 55.8 DZ CASSIOPEIAE = AN 216.1940 (P=0.78488636)
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1a.dat 59 497 BVR observations of AV Hya
table1b.dat 59 524 BVR observations of DZ Cas
table3.dat 47 130 All compiled light minimum times for AV Hya
table5.dat 47 97 All available times of minimum light for DZ Cas
refs.dat 84 74 References
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2012)
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2013)
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
II/150 : Parameters of eclipsing binaries (Brancewicz+, 1980)
J/AJ/143/13 : Al Gem and BM Mon light curves - Paper III (Yang+, 2012)
J/other/IBVS/5984 : Minima and maxima of 503 variables (Hubscher, 2011)
J/other/JAVSO/38.183 : Time of minima of eclipsing binaries (Samolyk+, 2010)
J/other/IBVS/5918 : Minima and maxima of 452 variables (Hubscher+, 2010)
J/AJ/139/1360 : AO Ser VR light curves - Paper II (Yang+, 2010)
J/AJ/137/226 : TV Tri differential light curves - Paper I (Yang+, 2009)
J/A+A/446/785 : Catalogue of eclipsing variables (Malkov+, 2006)
J/other/IBVS/5493 : 2003 CCD minima of eclipsing binaries (Nelson+, 2004)
J/A+A/417/263 : Catalogue of Algol type binary stars (Budding+, 2004)
J/other/IBVS/5543 : 163-nd list of minima of EBs (Diethelm+, 2004)
J/other/IBVS/5296 : Extrema of pulsating stars (Agerer+, 2002)
Byte-by-byte Description of file: table1[ab].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d HJD-B ? Heliocentric Julian Date of B band observation
14- 19 F6.3 mag DBmag ? Differential B band magnitude
21- 32 F12.4 d HJD-V ? Heliocentric Julian Date of V band observation
34- 39 F6.3 mag DVmag ? Differential V band magnitude
41- 52 F12.4 d HJD-R ? Heliocentric Julian Date of R band observation
54- 59 F6.3 mag DRmag ? Differential R band magnitude
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Byte-by-byte Description of file: table[35].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d HJD Heliocentric Julian Date
14- 21 F8.1 --- Epoch Epoch
23- 25 A3 --- Meth Detection method (vi=visual, pg=photographic,
CCD=CCD detector and pe=photometric)
27- 28 A2 --- Min Minimum type (I or II)
30- 36 F7.4 --- (O-C)1 Kreiner et al. (2001aocd.book.....K 2001aocd.book.....K) ephemeris
residuals (1)
38- 44 F7.4 --- (O-C)2 Irwin (1952ApJ...116..211I 1952ApJ...116..211I) light-time orbit
residuals (2)
46- 47 I2 --- Ref [1/89] Reference, in refs.dat file
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Note (1): Computed using the ephemeris given in equation (1) in the paper for
Table 3 and in equation (3) for Table 5.
Note (2): Computed using the ephemeris given in equation (2) in the paper.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref [1/89] Reference number
4- 22 A19 --- BibCode Bibliographic code
24- 43 A20 --- Aut Author's name
45- 84 A40 --- Com Comments
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History:
From electronic version of the journal
References:
Yang et al. Paper I 2009AJ....137..226Y 2009AJ....137..226Y Cat. J/AJ/137/226
Yang et al. Paper II 2010AJ....139.1360Y 2010AJ....139.1360Y Cat. J/AJ/139/1360
Yang et al. Paper III 2012AJ....143...13Y 2012AJ....143...13Y Cat. J/AJ/143/13
Yang et al. Paper V 2012AJ....144..136Y 2012AJ....144..136Y Cat. J/AJ/144/136
Yang et al. Paper VI 2014AJ....147...35Y 2014AJ....147...35Y Cat. J/AJ/147/35
Zhang et al. Paper VII 2014AJ....147...66Z 2014AJ....147...66Z Cat. J/AJ/147/66
Yang et al. Paper VIII 2014AJ....147..145Y 2014AJ....147..145Y Cat. J/AJ/147/145
Yang et al. Paper IX 2016AJ....152...49Y 2016AJ....152...49Y Cat. J/AJ/152/49
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 04-Oct-2013