J/MNRAS/498/2833 Algol eclipsing binaries in the Catalina Survey (Carmo+, 2020)
Recovering variable stars in large surveys:
EAup Algol-type class in the Catalina Survey.
Carmo A., Ferreira Lopes C.E., Papageorgiou A., Jablonski F.J.,
Rodrigues C.V., Drake A.J., Cross N.J.G., Catelan M.
<Mon. Not. R. Astron. Soc., 498, 2833-2844 (2020)>
=2020MNRAS.498.2833C 2020MNRAS.498.2833C (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, double and multiple ;
Binaries, orbits ; Stars, variable ; Effective temperatures ;
Stars, masses ; Stars, diameters ; Stars, distances ; Optical
Keywords: methods: data analysis - techniques: photometric -
astronomical data bases: miscellaneous - stars: late-type -
stars: low-mass - stars: variables: general
Abstract:
The discovery and characterization of Algol eclipsing binaries (EAs)
provide an opportunity to contribute for a better picture of the
structure and evolution of low-mass stars. However, the cadence of
most current photometric surveys hinders the detection of EAs since
the separation between observations is usually larger than the
eclipse(s) duration and hence few measurements are found at the
eclipses. Even when those objects are detected as variable, their
periods can be missed if an appropriate oversampling factor is not
used in the search tools. In this paper, we apply this approach to
find the periods of stars catalogued in the Catalina Real-Time
Transient Survey (CRTS) as EAs having unknown period (EAup). As a
result, the periods of ∼56 per cent of them were determined. Eight
objects were identified as low-mass binary systems and modelled with
the Wilson & Devinney synthesis code combined with a Markov chain
Monte Carlo optimization procedure. The computed masses and radii are
in agreement with theoretical models and show no evidence of inflated
radii. This paper is the first of a series aiming to identify
suspected binary systems in large surveys.
Description:
The CRTS (http://crts.caltech.edu/) consists of a collaboration in
which three telescopes are used aiming to discover near-Earth objects
(NEOs) and potentially hazardous asteroids (PHAs)
(https://catalina.lpl.arizona.edu). The project covers the sky in the
range of declinations δ=[-75°,+65°] and avoids crowded
regions near to the Galactic plane (|b|<15°). The images are
unfiltered to maximize the throughput and the photometry is carried
out using the sextractor photometry package (Bertin & Arnouts
1996A&AS..117..393B 1996A&AS..117..393B). Based on data from the 0.7-m Catalina Schmidt
Survey (CSS) telescope, Drake et al. (2012AAS...21942820D) identified
47000 variable sources from the public Catalina Data Release 1 (CSDR1;
Drake et al. 2012AAS...21942820D), which together with objects from
the other surveys produced an on-line catalogue of 61000 variable
objects. Among them, 4680 objects are classified as Algol eclipsing
(EA) binary systems.
For the scope of this work, we focus on the 153 EAup systems listed
in Drake et al. (2014ApJS..213....9D 2014ApJS..213....9D, Cat. J/ApJS/213/9), which were
classified as unknown-period eclipsing binary candidates. In other
words, these are objects that present variability typical of eclipsing
variables (i.e. excursions to lower states of brightness) but had an
insufficient number of observations in the eclipses for full
characterization.
Table A1 shows the parameters related to the period search in the
EAup sample. Convincing light curves were obtained for 87 sources.
We will refer to this set of objects as 'iEA': a shortcut for 'sample
of newly identified eclipsing binaries among the EAup of Drake et
al. (2014ApJS..213....9D 2014ApJS..213....9D, Cat. J/ApJS/213/9)'.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 136 8 Absolute parameters of the stellar components of
the low-mass binary system candidates
tablea1.dat 58 87 Parameters for the iEA stars identified in this
work
tableb1.dat 92 8 Parameters obtained from the model fits to the
light curves
tableb2.dat 90 8 Parameters obtained from the redone model fits
in order to improve parameters
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See also:
J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name CRTS system name (CSS JHHMMSS.s-DDMMSS)
22- 34 I13 --- ID CSS system identifier
36- 45 F10.8 d Period Orbital period
47- 50 I4 K Teff Effective temperature of the system
52- 55 I4 K T1 Effective temperature of the primary star
57- 60 I4 K T2 Effective temperature of the secondary star
62- 65 F4.2 Msun M1 Mass of the primary star
67- 70 F4.2 Msun E_M1 Upper error on M1 (1)
72- 75 F4.2 Msun e_M1 Lower error on M1 (1)
77- 80 F4.2 Msun M2 Mass of the secondary star
82- 85 F4.2 Msun E_M2 Upper error on M2 (1)
87- 90 F4.2 Msun e_M2 Lower error on M2 (1)
92- 95 F4.2 Rsun R1 Radius of the primary star
97- 100 F4.2 Rsun E_R1 Upper error on R1 (1)
102- 105 F4.2 Rsun e_R1 Lower error on R1 (1)
107- 110 F4.2 Rsun R2 Radius of the secondary star
112- 115 F4.2 Rsun E_R2 Upper error on R2 (1)
117- 120 F4.2 Rsun e_R2 Lower error on R2 (1)
122- 126 F5.2 Rsun a Semi-major axis
128- 131 F4.2 Rsun E_a Upper error on a (1)
133- 136 F4.2 Rsun e_a Lower error on a (1)
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Note (1): The errors were estimated considering an accuracy of the effective
temperature from Gaia of 324K
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name CRTS system name (CSS JHHMMSS.s-DDMMSS)
22- 29 F8.5 d Period Orbital period
31- 37 F7.5 d e_Period Error on Period
39- 43 F5.2 mag Vmag CSS V-band magnitude
45- 48 F4.2 mag A Amplitude
50- 53 F4.2 mag e_A Error on A
55- 58 F4.2 --- logNcyc Logarithm of the number of cycles (log
(Ttot/P))
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name CRTS system name (CSS JHHMMSS.s-DDMMSS)
22- 34 I13 --- ID CSS system identifier
36- 39 I4 K T1 Effective temperature of the primary star
(fixed)
41- 44 F4.2 --- T2/T1 Effective temperature ratio
(secondary to primary)
46- 49 F4.2 --- e_T2/T1 Error on T2/T1
51- 54 F4.2 --- (R1+R2)/a Sum of fractional radii
56- 59 F4.2 --- e_(R1+R2)/a Error on R1+R2)/a
61- 65 F5.2 deg i Inclination
67- 70 F4.2 deg e_i Error on i
72- 76 F5.2 --- Omega1 Modified Kopal potential Ω1
78- 81 F4.2 --- e_Omega1 Error on Omega1
83- 87 F5.2 --- Omega2 Modified Kopal potential Ω2
89- 92 F4.2 --- e_Omega2 Error on Omega2
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Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name CRTS system name (CSS JHHMMSS.s-DDMMSS)
22- 34 I13 --- ID CSS system identifier
36- 39 F4.2 --- T2/T1 Effective temperature ratio
(secondary to primary) (fixed)
41- 44 F4.2 --- (R1+R2)/a Sum of fractional radii
46- 49 F4.2 --- e_(R1+R2)/a Error on R1+R2)/a
51- 55 F5.2 deg i Inclination
57- 60 F4.2 deg e_i Error on i
62- 66 F5.2 --- Omega1 Modified Kopal potential Ω1
68- 71 F4.2 --- e_Omega1 Error on Omega1
73- 77 F5.2 --- Omega2 Modified Kopal potential Ω2
79- 82 F4.2 --- e_Omega2 Error on Omega2
84- 86 I3 pc Dist Distance estimated from the fitted
parameters
88- 90 I3 pc e_Dist Error on Dist
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 04-Aug-2023