J/AJ/147/145 Algol-type binaries. VIII. DI Peg & AF Gem (Yang+, 2014)
Photometric properties for selected Algol-type binaries.
VIII. The triple systems DI Peg and AF Gem revisited.
Yang Y.-G., Yang Y., Li S.-Z.
<Astron. J., 147, 145 (2014)>
=2014AJ....147..145Y 2014AJ....147..145Y
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI ; Photometry, CCD
Keywords: binaries: close - binaries: eclipsing -
stars: individual: (DI Peg,AF Gem)
Abstract:
New extensive photometry for two triple binary stars, DI Peg and AF
Gem, was performed from 2012 October to 2013 January, with two small
telescopes at Xinglong station (XLs) of NAOC. From new multi-color
observations and previously published ones in literature, the
photometric models were (re)deduced using the updated Wilson-Devinney
code. The results indicated that the low third lights exist in two
classic Algol-type binaries, whose fill-out factors for the more
massive components are fp=78.2(±0.4)% for DI Peg, and
fp=69.0(±0.3)% for AF Gem, respectively. Through analyzing the O-C
curves, the orbital periods for two binaries change in the complicated
mode. The period of DI Peg possibly appears to show two light-time
orbits, whose modulated periods are P3=54.6(±0.5)yr and
P4=23.0(±0.6)yr, respectively. The inferred minimum masses for the
inner and outer sub-stellar companions are Min=0.095M☉ and
Mout=0.170M☉, respectively. Therefore, DI Peg may be a
quadruple star. The orbital period of AF Gem appears to show a
continuous period decrease or a cyclic variation; the latter may be
preferable. The cyclic oscillation, with a period of 120.3(±2.5)yr,
may be attributed to the light-time effect due to the third body. This
kind of additional companion may extract angular momentum from the
central system, which may play a key role in the evolution of the
binary.
Description:
In the 2012-2013 observing season, DI Peg and AF Gem were observed
using the 60cm telescope and the 85cm telescope at Xinglong station
(XLs) of National Astronomical Observatories of Chinese (NAOC). The
standard Johnson-Cousins UBVRcIc photometric systems were mounted
upon two small telescopes. On five consecutive nights from 2012
October 9 to 13, the multi-color photometry of DI Peg was made with
the 60cm telescope. The other variable star, AF Gem, was observed using
the 85cm telescope on 7 nights from 2013 January 1 to 7.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars 16 2 The two Algol-type binaries DI Peg and AF Gem
table1.dat 66 1879 Photometric observations for two Algol-type
binaries DI Peg and AF Gem
table3.dat 56 485 All compiled eclipsing times of DI Peg
table4.dat 56 226 All available minimum light times of the
eclipsing binary AF Gem
refs.dat 84 295 *References
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Note on refs.dat: No more information was provided by any of the authors.
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2013)
J/AJ/147/66 : Algol-type binaries light curves. VII. V404 And (Zhang+, 2014)
J/AJ/147/35 : Light curves of Algol-type binaries. VI. FR Ori (Yang+, 2014)
J/AJ/144/136 : Light curves of the Algol-type binary V1241 Tauri (Yang+, 2012)
J/AJ/144/50 : Light curves of AV Hya and DZ Cas (Yang+, 2012)
J/AJ/143/13 : Light curves of AL Gem and BM Mon (Yang+, 2012)
J/AJ/139/1360 : AO Ser VR light curves (Yang+, 2010)
J/AJ/137/226 : Differential light curves of TV Tri (Yang+, 2009)
J/A+A/417/263 : Catalogue of Algol type binary stars (Budding+, 2004)
Byte-by-byte Description of file: stars
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Name of the variable
8- 16 F9.7 d Per Period
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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- 6 A6 --- Name Variable name (AF Gem or DI Peg)
8- 19 F12.4 d HJD-B ? B band Heliocentric Julian Date
21- 26 F6.3 mag DBmag ? Differential B band magnitude
28- 39 F12.4 d HJD-V ? V band Heliocentric Julian Date
41- 46 F6.3 mag DVmag ? Differential V band magnitude
48- 59 F12.4 d HJD-R ? R band Heliocentric Julian Date
61- 66 F6.3 mag DRmag ? Differential V band magnitude
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Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date
14- 21 F8.1 --- Epoch Epoch
23- 25 A3 --- Meth Observational method used (1)
27- 28 A2 --- Min Minimum type (I or II)
30- 36 F7.4 d O-C1 Eclipse time residual (O-C)1 (2)
38- 44 F7.4 d O-C2 Eclipse time residual (O-C)2 (3)
46- 52 F7.4 d O-C3 ? Eclipse time residual (O-C)3 (4)
54- 56 I3 --- Ref [1/315] Reference; in refs.dat file
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Note (1): Methods used are defined as follows:
CCD = Charge-Coupled Device;
pe = photoelectric;
pg = photographic;
vi = visual.
Note (2): For DI Peg (Table3), computed by the following ephemeris
Min.I=HJD2425918.361+0.71181641*E (Equation (1)) from all eclipsing times.
For AF Gem (Table4), computed by the linear ephemeris
Min.I=HJD2427162.3139+1.24350075*E (Equation (5)) from all eclipsing times.
Note (3): For DI Peg (Table3), removed by Equation (2):
Min.I=HJD24525918.3576(±0.0009)+0.71181646(±0.00000006)*E+τ
(where τ is LITE), and Equation (3), from (O-C)1s.
For AF Gem (Table4), removed by the following quadratic formula
(O-C)1=-0.0052(±0.0002)+0.0181(±0.0002)*E-9.52(±0.66)*10-11*E2
(Equation (6)) from (O-C)1s.
Note (4): For DI Peg (Table3), dervied from (O-C)2s by Equation (4):
(O-C)2=+0.0008(±0.0002)+τ. For AF Gem (Table4), dervied from
(O-C)2s by Equation (7).
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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- 3 I3 --- Ref [1/315] Reference identifier
5- 23 A19 --- BibCode Bibliographic code
25- 49 A25 --- Aut Author's name
51- 84 A34 --- Com Comments
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History:
From electronic version of the journal
References:
Yang & Wei, 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 IV, 2012AJ....144...50Y 2012AJ....144...50Y, Cat. J/AJ/144/50
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 IX, 2016AJ....152...49Y 2016AJ....152...49Y, Cat. J/AJ/152/49
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 06-Oct-2014