J/MNRAS/514/5528 Study of contact binaries in CoBiToM II (Loukaidou+, 2022)
CoBiToM Project - II. Evolution of contact binary systems close to the orbital
period cut-off.
Loukaidou G.A., Gazeas K.D., Palafouta S., Athanasopoulos D., Zola S.,
Liakos A., Niarchos P.G., Hakala P., Essam A., Hatzidimitriou D.
<Mon. Not. R. Astron. Soc. 514, 5528-5547 (2022)>
=2022MNRAS.514.5528L 2022MNRAS.514.5528L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Binaries, eclipsing ; Photometry ;
Observatory log ; Optical ; Parallaxes, trigonometric ;
Spectroscopy ; Stars, distances ; Effective temperatures ;
Models ; Stars, masses ; Stars, diameters ; Mass loss ;
Positional data
Keywords: binaries: close - binaries: eclipsing - stars: evolution -
stars: fundamental parameters - stars: low-mass
Abstract:
Ultra-short orbital period contact binaries (Porb < 0.26 d) host some
of the smallest and least massive stars. These systems are faint and
rare, and it is believed that they have reached a contact
configuration after several Gyrs of evolution via angular momentum
loss, mass transfer, and mass loss through stellar wind processes.
This study is conducted in the frame of the Contact Binaries Towards
Merging (CoBiToM) Project and presents the results from light curve
and orbital analysis of 30 ultra-short orbital period contact
binaries, with the aim to investigate the possibility of them being
red nova progenitors, eventually producing merger events.
Approximately half of the systems exhibit orbital period modulations,
as a result of mass transfer or mass loss processes. Although they are
in contact, their fill-out factor is low (less than 30 per cent),
while their mass ratio is larger than the one in longer period contact
binaries. This study investigates the orbital stability of these
systems and examines their physical and orbital parameters in
comparison to those of the entire sample of known and well-studied
contact binaries, based on combined spectroscopic and photometric
analysis. It is found that ultra-short orbital period contact binaries
have very stable orbits, while very often additional components are
gravitationally bound in wide orbits around the central binary system.
We confirmed that the evolution of such systems is very slow, which
explains why the components of ultra-short orbital period systems are
still Main Sequence stars after several Gyrs of evolution.
Description:
In this study, we focus our work on a sample of 30 ultra-short orbital
period contact binary systems presented and examined under the scope
of their physical and orbital properties. All systems were
homogeneously observed and analysed, and only a few of them have been
previously investigated in other studies using their light curves, O
-C diagrams and physical parameters at the same time. Therefore, we
present the analysis of recent and unpublished multiband photometric
observations with well known and accurate techniques, combined with
all the available spectroscopic data.
This sample was selected from the SWASP catalogue using main criteria
of a contact binary classification and an orbital period shorter than
0.26 d. Additionally, targets should have multi-epoch data covering
approximately 3-7 yr, thus ensuring a sufficient number of times of
minimum light and hence a wide time span in the orbital period
analysis through O-C diagrams. Firstly, as indicated in section 2, for
all 30 systems, we compiled in table1.dat observation logs, T0(HJD)
and Porb(d) values. Secondly, we processed to data analysis and
light-curve modelling on observation data and additional online data
(i.e details in section 3.1 Times of minimum light and linear
ephemerides). Next, as we need temperature of the primary component as
prior for light curve modelling, we extracted it based on photometric
and spectroscopic surveys. These results are provided in table2.dat.
Fully explained in section 3.3 Light-curve modelling, resulting models
provide the physical and geometrical parameters of the systems as
exposed in tablea1-a6.dat. These severals data allowed us to computed
absolute parameters as mass, radius and luminosity of the 30 systems
presented in table3.dat (i.e computation methodsare available in
section 4). Finally, O-C diagrams is the best way to detect possible
period variations and study their orbital parameters. We produced O-C
diagrams using section 5 procedure. This work gave birth to orbital
period modulation parameters derivation as exposed in table4.dat. This
parameters include for 12 targets, time modulations of secular period,
mass transfer and mass loss.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 133 30 Observation log of all ultra-short contact
binaries targets with their linear ephemerides
for phasing observations
table2.dat 95 30 Astrometric and photometric parameters of all
ultra-short contact binaries targets
table3.dat 98 30 *Absolute mass and radius parameters of all
ultra-short contact binaries targets
table4.dat 113 30 Orbital period modulation parameters as derived
from the O-C diagram analysis accompanied with
the corresponding mass transfer and loss rates
tablea1.dat 292 5 *Resulting from light-curve modelling providing
the physical and geometrical parameters - I
tablea2.dat 292 5 *Resulting from light-curve modelling providing
the physical and geometrical parameters - II
tablea3.dat 292 5 *Resulting from light-curve modelling providing
the physical and geometrical parameters - III
tablea4.dat 292 5 *Resulting from light-curve modelling providing
the physical and geometrical parameters - IV
tablea5.dat 292 5 *Resulting from light-curve modelling providing
the physical and geometrical parameters - V
tablea6.dat 292 5 *Resulting from light-curve modelling providing
the physical and geometrical parameters - VI
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Note on table3.dat: The primary component refers to the larger and more massive
component of the targets.
Note on tablea1.dat and tablea2.dat and tablea3.dat and tablea4.dat : Here
L1X, L2X, l3X refer to relative luminosities in a specific photometric
filter U,B,V,R,I. They are dimensionless as they represent fractions of the
total system luminosity in a given bandpass where L1X + L2X + l3X is
almost equal to 1. Is it oftenly used in light-curve modelling, quantities
are normalized values in each photometric band.
Note on tablea5.dat and tablea6.dat: Here L1X, L2X, l3X refer to relative
luminosities in a specific photometric filter U,B,V,R,I. They are dimensionless
as they represent fractions of the total system luminosity in a given bandpass
where L1X + L2X + l3X is almost equal to 1. Is it oftenly used in
light-curve modelling, quantities are normalized values in each photometric
band.
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
II/336 : AAVSO Photometric All Sky Survey (APASS) DR9
(Henden+, 2016)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars
(Pecaut+, 2013)
J/AJ/134/2398 : Stellar SEDs in SDSS and 2MASS filters (Covey+, 2007)
J/MNRAS/448/2890 : Observation of six NSVS eclipsing binaries
(Dimitrov+, 2015)
J/A+A/528/A90 : SuperWASP short period eclipsing binaries (Norton+, 2011)
J/ApJS/249/18 : The ZTF catalog of periodic variable stars (Chen+, 2020)
J/MNRAS/503/3975 : Var., period. and contact binaries in WISE
(Petrosky+, 2021)
J/A+A/558/A71 : Times of minima for 1SWASP J234401.81-212229.1
(Lohr+, 2013)
J/other/RAA/20.163 : Contact binaries in LAMOST DR7 (Qian+, 2020)
J/AJ/151/68 : Kepler Mission. VII. Eclipsing binaries in DR3
(Kirk+, 2016)
J/A+A/619/A97 : CoRoT transit catalogue (Deleuil+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 26 A26 --- ID Target system identifier (SystemID)
28- 36 A9 --- GCVS GCVS identifier from 2017ARep...61...80S 2017ARep...61...80S,
Cat. B/gcvs (GCVSID)
38- 50 F13.5 d T0 Epoch of minimum light observation in HJD
unit (T0HJD)
52- 58 F7.5 d e_T0 Mean uncertainty of T0 (errT0HJD)
60- 69 F10.8 d Porb Orbiting period of the binary system (Porb)
71- 80 F10.8 d e_Porb Mean uncertainty of Porb (errPorb)
82- 98 A17 --- ObsSeason Observing season (Observingseason)
100-109 A10 --- Nights Number of observing nights (Nights)
111-114 A4 --- Filters Photometric filters used for observations
(Filters)
116-133 A18 --- Site Name of observatory site (Site) (1)
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Note (1): Observatory site are as follows:
UOAO = University of Athens Observatory, 22 targets in our sample
Kryoneri = Kryoneri Observatory of National Observatory of Athens,
3 targets in our sample
Helmos = Helmos Observatory of National Observatory of Athens,
6 targets in our sample
SAAO = South African Astronomical Observatory,
15 targets in our sample
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 26 A26 --- ID Target system identifier (SystemID)
28- 32 F5.2 mas plx ? Parallax (Parallax)
34- 37 F4.2 mas e_plx ? Mean uncertainty of the plx (errParallax)
39- 43 F5.1 pc D ? Distance (d)
45- 48 F4.1 pc e_D ? Mean uncertainty of d (errd)
50- 53 F4.2 mag VMAG ? Absolute magnitude in V filter from APASS DR9
Henden et al. 2015AAS...22533616H, Cat. II/336
(MV)
55- 58 F4.2 mag e_VMAG ? Mean uncertainty of VMag (errMV)
60- 63 F4.2 mag D1mag Photometric depth in light curve of the first
eclipse corresponding to an apparent brightness
decrease (minI)
65- 68 F4.2 mag D2mag Photometric depth in light curve of the second
eclipse corresponding to an apparent brightness
decrease (minII)
70- 73 I4 K TBV Temperature derived based on photometric colour
B-V index from APASS DR9 Henden et al.
2015AAS...22533616H, Cat. II/336 (TBV) (1)
75- 78 I4 K Tgi Temperature derived based on photometric colour
g-i index from APASS DR9 Henden et al.
2015AAS...22533616H, Cat. II/336 (Tgi) (2)
80- 88 A9 K Tsp Temperature of independent estimates in
additional spectroscopic data (Tsp)
90 I1 --- r_Tsp ? Literature reference of Tsp (refTsp) (3)
92- 95 I4 K Tm Rounded average effective temperature of the
primary component of the target (Tm) (4)
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Note (1): We calculated TBV as following the B-V index to TBV conversion
provided by Pecaut & Mamajek (2013ApJS..208....9P 2013ApJS..208....9P, Cat. J/ApJS/208/9).
Note (2): We calculated Tgi as following the g-i index to Tgi conversion
by Covey et al. (2007AJ....134.2398C 2007AJ....134.2398C, Cat. J/AJ/134/2398).
Note (3): For 11 targets, spectroscopic data were retrieved from the literature
as follows :
1 = Koen et al. 2016AJ....151..168K 2016AJ....151..168K, 8 targets in our sample
2 = Dimitrov & Kjurkchieva 2015MNRAS.448.2890D 2015MNRAS.448.2890D
Cat. J/MNRAS/448/2890, 1 target in our sample
3 = Lohr et al. 2015A&A...578A.103L 2015A&A...578A.103L, 1 target in our sample
4 = Lohr et al. 2014A&A...563A..34L 2014A&A...563A..34L, 1 target in our sample
Note (4): Assigned as prior for modelling process, the effective temperature of
the primary component in each system. It was calculated by averaging
the photometric values in columns TBV and Tgi and rounding the
value within 50 K in order to match the closest spectral type
(i.e more informations in section 3.2 Temperature information and
spectroscopy).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 26 A26 --- ID Target system identifier (SystemID)
28- 32 F5.3 Msun M1 Estimated mass of the primary component of the
binary system (M1)
34- 38 F5.3 Msun e_M1 Mean uncertainty of M1 (errM1)
40- 44 F5.3 Msun M2 Estimated mass of the secondary component of the
binary system (M2)
46- 50 F5.3 Msun e_M2 Mean uncertainty of M2 (errM2)
52- 56 F5.3 Rsun R1 Estimated radius of the primary component of the
binary system (R1)
58- 62 F5.3 Rsun e_R1 Mean uncertainty of R1 (errR1)
64- 68 F5.3 Rsun R2 Estimated radius of the secondary component of the
binary system (R2)
70- 74 F5.3 Rsun e_R2 Mean uncertainty of R2 (errR2)
76- 80 F5.3 Lsun L1 Estimated luminosity of the primary component of
the binary system (L1)
82- 86 F5.3 Lsun e_L1 Mean uncertainty of L1 (errL1)
88- 92 F5.3 Lsun L2 Estimated luminosity of the secondary component of
the binary system (L2)
94- 98 F5.3 Lsun e_L2 Mean uncertainty of L2 (errL2)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 26 A26 --- ID Target system identifier (SystemID)
28- 33 F6.2 yr P3 ? The estimated period of the tertiary
component (P3)
35- 39 F5.2 yr e_P3 ? Mean uncertainty of P3 (errP3)
41- 46 F6.4 d A ? The amplitude of the cyclic variation
from the O-C analysis (A)
48- 53 F6.4 d e_A ? Mean uncertainty of A (errA)
55- 58 F4.2 Msun M3min ? The possible minimum mass of the
tertiary component in a co-planar orbit
(M3min)
60- 63 F4.2 Msun e_M3min ? Mean uncertainty of M3min (errM3min)
65- 69 F5.3 au a12sini3 ? The value of a12sini3 distance
(a12sini3) (1)
71- 75 F5.3 au e_a12sini3 ? Mean uncertainty of a12sini3
(erra12sini3)
77- 82 F6.3 10-7d/yr dP/dt ? Time modulation of the secular
orbital period (dP/dt)
84- 88 F5.3 10-7d/yr e_dP/dt ? Mean uncertainty of dP/dt (errdP/dt)
90- 95 F6.2 10-7Msun/yr dMT/dt ? The estimated mass transfer between
the two main components (dMT/dt)
97-101 F5.2 10-7Msun/yr e_dMT/dt ? Mean uncertainty of dMT/dt (errdMT/dt)
103-108 F6.2 10-7Msun/yr dML/dt ? The estimated mass loss of the system
(dML/dt)
110-113 F4.2 10-7Msun/yr e_dML/dt ? Mean uncertainty of dML/dt (errdML/dt)
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Note (1): As described in the section 5 Orbital period modulation, a12 is the
projected semimajor axis and i3 is the orbital inclination of the
tertiary component with respect to the system's orbital plane.
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Byte-by-byte Description of file: tablea?.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 26 A26 --- ID Target system identifier (SystemID)
28- 29 I2 % f The fill-out factor parameter (Fill-out)
31- 32 I2 % e_f Mean uncertainty of f (errFill-out)
34- 37 F4.1 deg i Inclination angle (i)
39- 41 F3.1 deg e_i Mean uncertainty of i (erri)
43- 46 I4 K T1 Effective temperature of the primary component
as fixed parameter (T1)
48- 51 I4 K T2 Effective temperature of the secondary
component as fixed parameter (T2)
53- 54 I2 K e_T2 Mean uncertainty of T2 (errT2)
56- 60 F5.3 m2/s2 Omega The gravitational potential
Ω1 = Ω2
62- 66 F5.3 m2/s2 e_Omega Mean uncertainty of Omega (errOmega)
68- 72 F5.3 --- qph ? Photometric mass ratio (qph)
74- 78 F5.3 --- e_qph ? Mean uncertainty of qph (errqph)
80- 84 F5.3 --- L1(U) ? The luminosity of the primary component in U
photometric filter (L1U)
86- 90 F5.3 --- e_L1(U) ? Mean uncertainty of L1 (U) (errL1U)
92- 96 F5.3 --- L1(B) ? The luminosity of the primary component in B
photometric filter (L1B)
98-102 F5.3 --- e_L1(B) ? Mean uncertainty of L1 (B) (errL1B)
104-108 F5.3 --- L1(V) The luminosity of the primary component in V
photometric filter (L1V)
110-114 F5.3 --- e_L1(V) Mean uncertainty of L1 (V) (errL1V)
116-120 F5.3 --- L1(R) The luminosity of the primary component in R
photometric filter (L1R)
122-126 F5.3 --- e_L1(R) ? Mean uncertainty of L1 (R) (errL1R)
128-132 F5.3 --- L1(I) ? The luminosity of the primary component in I
photometric filter (L1I)
134-138 F5.3 --- e_L1(I) ? Mean uncertainty of L1 (I) (errL1I)
140-144 F5.3 --- L2(U) ? Relative luminosity according to L1 of the
secondary star in U photometric filter (L2U)
146-150 F5.3 --- L2(B) ? Relative luminosity according to L1 of the
secondary star in B photometric filter (L2B)
152-156 F5.3 --- L2(V) ? Relative luminosity according to L1 of the
secondary star in V photometric filter (L2V)
158-162 F5.3 --- L2(R) ? Relative luminosity according to L1 of the
secondary star in R photometric filter (L2R)
164-168 F5.3 --- L2(I) ? Relative luminosity according to L1 of the
secondary star in I photometric filter (L2I)
170-174 F5.3 --- l3(U) ? The third light of the additional companion
in U photometric filter (l3U)
176-180 F5.3 --- l3(B) ? The third light of the additional companion
in B photometric filter (l3B)
182-186 F5.3 --- e_l3(B) ? Mean uncertainty of l3 (B) (errl3B)
188-192 F5.3 --- l3(V) The third light of the additional companion in
V photometric filter (l3V)
194-198 F5.3 --- e_l3(V) ? Mean uncertainty of l3 (V) (errl3V)
200-204 F5.3 --- l3(R) The third light of the additional companion in
R photometric filter (l3R)
206-210 F5.3 --- e_l3(R) ? Mean uncertainty of l3 (R) (errl3R)
212-216 F5.3 --- l3(I) ? The third light of the additional companion
in I photometric filter (l3I)
218-222 F5.3 --- e_l3(I) ? Mean uncertainty of l3 (I) (errl3I)
224-229 F6.4 --- r1side Orbital angular momentum ratio from the side of
the primary component (r1side)
231-236 F6.4 --- r2side Orbital angular momentum ratio from the side of
the secondary star (r2side)
238-244 F7.3 deg CoLAT ? Co-latitude angle of the target system
(Co-latitude)
246-251 F6.3 deg e_CoLAT ? Mean uncertainty of CoLAT (errCoLAT)
253-260 F8.4 deg LON ? Longitude angle of the target system
(Longitude)
262-267 F6.4 deg e_LON ? Mean uncertainty of LON (errLongitude)
269-273 F5.1 Rsun R ? Radius of the target system (Radius)
275-278 F4.1 Rsun e_R ? Mean uncertainty of R (errRadius)
280-286 F7.3 --- fT ? Temperature factor value (Tempfactor)
288-292 F5.3 --- e_fT ? Mean uncertainty of fT (errTempfactor)
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History:
From electronic version of the journal
References:
Gazeas et al., Paper I 2021MNRAS.502.2879G 2021MNRAS.502.2879G
(End) Luc Trabelsi [CDS] 28-May-2025