J/MNRAS/485/2562 Eclipse timing variation of eclipsing binaries (Hajdu+, 2019)
Eclipse timing variation analysis of OGLE-IV eclipsing binaries towards the
Galactic Bulge - I. Hierarchical triple system candidates.
Hajdu T., Borkovits T., Forgacs-Dajka E., Sztakovics J., Marschalko G.,
Kutrovatz G.
<Mon. Not. R. Astron. Soc., 485, 2562-2572 (2019)>
=2019MNRAS.485.2562H 2019MNRAS.485.2562H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Binaries, eclipsing;
Binaries, orbits ; Optical
Keywords: methods: numerical - binaries: close - binaries: eclipsing
Abstract:
We report a study of the eclipse timing variation (ETV) of short
period (P1=<6d) eclipsing binaries (EBs) monitored during the
photometric survey optical gravitational lensing experiment-IV. From
the 425193 EBs, we selected approximately 80000 binaries that we found
suitable for further examination. Among them, we identified 992
potential hierarchical triple (or multiple) system candidates
exhibiting light-travel time effect (LTTE). Besides, we obtained the
orbital parameters of these systems and carried out statistical
analyses on the properties of these candidates. We found that (i)
there is a significant lack of triple systems where the outer period
is less than 500d, (ii) the distribution of the outer eccentricities
has a maximum around e2∼0.3, and (iii) the outer mass ratio
calculated from an estimated minimum mass of the third component is
lower than q2∼0.5 for the majority of the sample. We also present
some systems that deserve special attention: (i) There are four
candidates that show double periodic ETV, which we explain by the
presence of a fourth companion; (ii) For two systems, the
perturbations of the third component are also found to be significant
therefore we give a combined dynamical and LTTE ETV solution; and
(iii) For one system, the third component is found to be probably in
the substellar mass domain.
Description:
The OGLE-IV survey (Soszynski et al. 2016AcA....66..405S 2016AcA....66..405S, Cat.
J/AcA/66/405) provided around 425193 light curves of EBs that were
observed in I and V bands. Since the I band light curves typically
contain much more points than V band ones, we relied only on the
former photometric band data for our analysis. Observations of the
currently running project OGLE-IV are made at Las Campanas
Observatory, Chile with the 1.3m Warsaw Telescope, which is currently
equipped with a mosaic CCD camera.
Our main goal was to find hierarchical triple stellar candidates whose
outer period (P2) is shorter than, or comparable to, the length of the
observations. Unfortunately, most of the data trains do not contain
enough data points (more than the half of the cases contain less than
1000 points) for a detailed examination. Therefore, we investigated
only those systems whose light curves contain more than 4000 points.
Applying this criterion, we reduced our sample from the original
425193 EBs to ∼80000 systems.
Owing to the long-term observations, we were able to find 992 third
body candidates. For the more reliable results, we selected 258
systems where the period and the eccentricity were estimated with
lower uncertainties (see Table 1).
For four of them (OGLE-BLG-ECL-136469, OGLE-BLG-ECL-153291,
OGLE-BLG-ECL-165849, and OGLE-BLG-ECL-259162), we came to the
conclusion that their ETVs can be well modelled with a double LTTE
solution rather than a simple hierarchical stellar system solution
(see Table 4). However, since our model neglects dynamic effects, the
resulting parameters are only indicative.
We also found two systems with significant dynamical amplitudes
(OGLE-BLG-ECL-143356 and OGLE-BLG-ECL-169255), described in Table 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 126 258 LTTE solutions for the 258 most certain
hierarchical triple star candidates of the
OGLE-IV sample
table2.dat 114 730 LTTE solutions for the remaining, less certain
hierarchical triple star candidates of the
OGLE-IV sample
table3.dat 155 2 Orbital elements from combined dynamical and
LTTE solutions
table4.dat 181 4 Results of double LTTE solution fit
table5.dat 48 7 The seven systems where the third component has
higher mass than the EB
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See also:
J/AcA/66/405 : Galactic bulge eclipsing & ellipsoidal binaries
(Soszynski+, 2016)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID OGLE-BLG-ECL identifier (NNNNNN)
8- 18 F11.6 d T0 Epoch (HJD-2450000d)
20- 27 F8.6 d P1 Inner period
29- 36 F8.2 d P2 Outer period
38- 45 F8.1 d e_P2 Error on P2
47- 52 F6.1 Rsun asini2 Projected semi-major axis of the light-time
orbit
54- 59 F6.1 Rsun e_asini2 Error on asini2
61- 64 F4.2 --- e2 Eccentricity
66- 69 F4.2 --- e_e2 Error on e2
71- 76 F6.1 deg omega2 Argument of the periastron
78- 82 F5.1 deg e_omega2 Error on omega2
84- 90 F7.1 d tau2 Periastron passage time of the third companion
92- 98 F7.1 d e_tau2 Error on tau2
100-106 F7.5 --- fmC Mass function
108-114 F7.5 --- e_fmC Error on fmC
116-121 F6.1 --- DeltaP1 ? Parabolic term (1)
123-126 F4.1 --- e_DeltaP1 ? Error on DeltaP1 (1)
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Note (1): The value of the parabolic term was listed in those cases where it
was necessary to use parabolic component to fit the eclipse timing
variations ETV
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID OGLE-BLG-ECL identifier (NNNNNN)
8- 18 F11.6 d T0 Epoch (HJD-2450000d)
20- 27 F8.6 d P1 Inner period
29- 34 F6.2 d P2 Outer period
36- 39 F4.2 d e_P2 Error on P2
41- 46 F6.2 Rsun asini2 Projected semi-major axis of the light-time
orbit
48- 52 F5.2 Rsun e_asini2 Error on asini2
54- 57 F4.2 --- e2 Eccentricity
59- 62 F4.2 --- e_e2 Error on e2
64- 69 F6.2 deg omega2 Argument of the periastron
71- 75 F5.2 deg e_omega2 Error on omega2
77- 83 F7.2 d tau2 Periastron passage time of the third
companion
85- 89 F5.2 d e_tau2 Error on tau2
91- 96 F6.4 d ALTTE Light-travel time effect (LTTE) amplitude
98-103 F6.4 d e_ALTTE Error on ALTTE
105-110 F6.4 d Adyn Amplitude-like quantity of the dynamical
eclipse timing variation (ETV) component
112-115 F4.2 --- Adyn/ALTTE Adyn to ALTTE ratio
117-120 F4.2 --- fmC Mass function
122-125 F4.2 --- e_fmC Error on fmC
127-130 F4.2 --- mC/mABC mC to mABC mass ratio
132-135 F4.2 --- e_mC/mABC Error on mC/mABC
137-140 F4.2 Msun mAB Total mass of the inner binary
142-145 F4.2 Msun e_mAB Error on mAB
147-150 F4.2 Msun mC Mass of the third component
152-155 F4.2 Msun e_mC Error on mC
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID OGLE-BLG-ECL identifier (NNNNNN)
8- 18 F11.6 d T0 Epoch (HJD-2450000d)
20- 27 F8.6 d P1 Inner period
29- 34 F6.2 d P2 Outer period of the first light-travel time
effect (LTTE)
36- 39 F4.2 d e_P2 Error on P2
41- 46 F6.2 Rsun asini2 Projected semi-major axis of the light-time or
bit associated to the first LTTE
48- 52 F5.2 Rsun e_asini2 Error on asini2
54- 57 F4.2 --- e2 Eccentricity associated to the first LTTE
59- 62 F4.2 --- e_e2 Error on e2
64- 69 F6.2 deg omega2 Argument of the periastron associated to the
first LTTE
71- 75 F5.2 deg e_omega2 Error on omega2
77- 83 F7.2 d tau2 Periastron passage time of the third companion
associated to the first LTTE
85- 89 F5.2 d e_tau2 Error on tau2
91- 96 F6.4 --- fmC Mass function associated to the first LTTE
98-102 F5.3 --- e_fmC Error on fmC
104-110 F7.2 d P3 Outer period of the second light-travel time
effect (LTTE)
112-117 F6.2 d e_P3 Error on P3
119-124 F6.2 Rsun asini3 Projected semi-major axis of the light-time or
bit associated to the first LTTE
126-130 F5.2 Rsun e_asini3 Error on asini3
132-135 F4.2 --- e3 Eccentricity associated to the first LTTE
137-140 F4.2 --- e_e3 Error on e3
142-147 F6.2 deg omega3 Argument of the periastron associated to the
first LTTE
149-153 F5.2 deg e_omega3 Error on omega3
155-161 F7.2 d tau3 Periastron passage time of the third companion
associated to the first LTTE
163-168 F6.2 d e_tau3 Error on tau3
170-175 F6.4 --- fmD Mass function associated to the first LTTE
177-181 F5.3 --- e_fmD Error on fmD
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID OGLE-BLG-ECL identifier (NNNNNN)
8- 15 F8.6 d P1 Inner period
17- 22 F6.1 d P2 Outer period
24- 28 F5.1 d e_P2 Error on P2
30- 33 F4.2 --- fmC Mass function
35- 38 F4.2 --- e_fmC Error on fmC
40- 43 F4.2 Msun mC Mass of the third component
45- 48 F4.2 Msun e_mC Error on mC
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 21-Sep-2022