J/A+A/710/A49 New sample of low mass ratio contact binary systems (Poro+, 2026)
Multivariate statistical analysis of contact binaries with a low mass ratio:
Definition, dynamical stability, and parameter relations.
Poro A., Poggiani R., Foroutanfar A., Harzandjadidi R., Kahali Poor N.,
Alicavus F.
<Astron. Astrophys. 710, A49 (2026)>
=2026A&A...710A..49P 2026A&A...710A..49P (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, masses ; Stars, diameters ; Optical
Keywords: methods: data analysis - binaries: eclipsing -
stars: fundamental parameters
Abstract:
This study explores multiple aspects of W Ursae Majoris (W UMa)
contact binary systems with low mass ratios. We provide empirical
insights into their definition, structure, rotational stability, and
parameter relations. We first examined the range of mass ratios that
characterize these systems, and based on an analysis of 818 contact
binaries, we established an empirical threshold of q∼0.27 to identify
systems with a low mass ratio. To investigate the rotational
stability, we conducted a Monte Carlo analysis of the squared gyration
radii (k12 and k22) and assessed the resulting spin-to-orbital
angular momentum ratio (Jspin/Jorb). While k1 remains nearly constant,
k2 and Jspin/Jorb decrease slightly with increasing mass ratio. This
emphasizes the role of the secondary star's internal structure.
Moreover, we compiled a dedicated sample of 115 contact binaries with
a low mass ratio and estimated their absolute parameters using Gaia
DR3 parallaxes. From this dataset, we derived empirical parameter
relations for systems with a low mass ratio that provide a useful
reference for future observational and theoretical studies. The
resulting datasets and statistical summaries offer benchmarks for
modeling, stability evaluation, and evolutionary studies of W UMa-type
binaries with low mass ratios.
Description:
This table contains the new sample of contact binary systems with a
low mass ratio used in the paper. It lists literature identifiers and
classifications, light-curve parameters, and absolute physical
parameters derived or adopted in the analysis.
Some systems may appear more than once if multiple literature
solutions or classifications were retained for comparison. Blank
entries denote unavailable values in the source data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 319 115 New sample of low mass ratio contact binary systems
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- System System name
30- 48 A19 --- Bibcode ADS bibliographic code of the reference source
50 A1 --- Subtype Contact-binary subtype (A or W)
52- 58 A7 --- EclType Eclipse type (Total or Partial)
60- 67 F8.6 d Period Orbital period
69- 70 A2 --- Method Source/method flag: SP or PH
72- 75 I4 K T1 Effective temperature of the primary component
77- 80 I4 K T2 Effective temperature of the secondary
component
82- 86 F5.3 --- q Mass ratio used in the literature source
88- 92 F5.3 --- invq ? Inverse mass ratio, when applicable
94- 98 F5.2 deg i Orbital inclination
100-104 F5.3 --- f Fillout factor
106-110 F5.3 --- l1 Luminosity contribution/fraction of the
primary component
112-116 F5.3 --- l2 Luminosity contribution/fraction of the
secondary component
118-122 F5.3 --- r1 Fractional radius of the primary component
124-128 F5.3 --- r2 Fractional radius of the secondary component
130-132 A3 --- l3 Third-light flag or contribution
134-136 A3 --- Spot Spot flag
138-142 F5.3 Msun M1 Mass of the primary component
144-148 F5.3 Msun e_M1 Uncertainty in M1
150-154 F5.3 Msun M2 Mass of the secondary component
156-160 F5.3 Msun e_M2 Uncertainty in M2
162-166 F5.3 Rsun R1 Radius of the primary component
168-172 F5.3 Rsun e_R1 Uncertainty in R1
174-178 F5.3 Rsun R2 Radius of the secondary component
180-184 F5.3 Rsun e_R2 Uncertainty in R2
186-190 F5.3 Lsun L1 Luminosity of the primary component
192-196 F5.3 Lsun e_L1 Uncertainty in L1
198-202 F5.3 Lsun L2 Luminosity of the secondary component
204-208 F5.3 Lsun e_L2 Uncertainty in L2
210-214 F5.3 mag Mbol1 Bolometric magnitude of the primary component
216-220 F5.3 mag e_Mbol1 Uncertainty in Mbol1
222-226 F5.3 mag Mbol2 Bolometric magnitude of the secondary
component
228-232 F5.3 mag e_Mbol2 Uncertainty in Mbol2
234-238 F5.3 [cm/s2] logg1 Surface gravity of the primary component
240-244 F5.3 [cm/s2] e_logg1 Uncertainty in logg1
246-250 F5.3 [cm/s2] logg2 Surface gravity of the secondary component
252-256 F5.3 [cm/s2] e_logg2 Uncertainty in logg2
258-262 F5.3 Rsun a Semimajor axis
264-268 F5.3 Rsun e_a Uncertainty in a
270-275 F6.3 --- logJ0 Logarithm of the orbital angular momentum
277-281 F5.3 --- e_logJ0 Uncertainty in logJ0
283-287 F5.3 mag Av Interstellar extinction in the V band
289-293 F5.3 mag e_Av Uncertainty in Av
295-300 F6.3 mag BC1 Bolometric correction of the primary component
302-306 F5.3 mag e_BC1 Uncertainty in BC1
308-313 F6.3 mag BC2 Bolometric correction of the secondary
component
315-319 F5.3 mag e_BC2 Uncertainty in BC2
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Acknowledgements:
Fahri Alicavus, fahrialicavus(at)comu.edu.tr
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 04-May-2026