J/A+A/697/A133 B, V and R band polarimetry of HD 165052 (Abdul Qadir+, 2025)
High-precision broadband linear polarimetry of early-type binaries.
V. The binary system HD 165052 in open cluster NGC 6530.
Abdul Qadir Y., Berdyugin A.V., Piirola V., Sakanoi T., Kagitan M.,
Berdyugina S.V.
<Astron. Astrophys. 697, A133 (2025)>
=2025A&A...697A.133A 2025A&A...697A.133A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Polarization ; Optical
Keywords: polarization - instrumentation: polarimeters -
techniques: polarimetric - binaries: close - binaries: general -
stars: individual: HD 165052
Abstract:
This is a continuation of our study of early-type binaries with
high-precision broad-band polarimetry. This time, we are presenting
results of our observations of the massive O+O-type binary system HD
165052 located in the very young open cluster NGC 6530. Our aim was to
investigate the variations of linear polarization in this system with
time and obtain independent estimate of orbital period from
polarization data. By fitting phase-locked variations of Stokes
parameters q and u, it is possible to obtain independent estimates of
orbit inclination i, orientation Ω, and the direction of
rotation.
We employed the Dipol-2 polarimeter in combination with the remotely
controlled 60cm KVA and Tohoku T60 telescopes. Linear polarization
measurements of HD 165052 were obtained in the B, V, and R passbands
with an accuracy better than ∼0.01%. Lomb-Scargle method of period
search was applied to the acquired polarization data to identify
present periodic signals. To study interstellar polarization in NGC
6530, we observed 25 cluster stars located in close proximity to the
binary.
Our observations clearly revealed periodic variations of Stokes
parameters in all three passbands with the amplitude ∼0.1%. Period
search, applied to polarization data, detected unambiguous and
strongest periodic signal at 1.47755±0.005d, that corresponds to
half of the orbital period of 2.95510±0.005d. Our independent period
search, performed on polarization data, supports a "shorter" value of
the orbital period in HD 165052 determined from RV measurements done
in the past and rejects "longer" value obtained very recently. In the
observed polarization variations, the second terms of the Fourier
harmonics are clearly dominating suggesting that light scattering
material is symmetrically distributed with respect to the orbital
plane. We concluded that the most probable polarization mechanism is
the electron scattering in the interacting stellar winds. To evaluate
the effect of non-periodic noise on the orbital parameters derived
from analysis of periodic variations of polarization, we have employed
rigorous Monte Carlo simulations for the available data. Thus, we
derived our best estimate of the orbital inclination i as
55+5-55°, and Ω as 148° (328+20-22° averaged
over B, V, and R passbands. Our estimates provide direct and
unambiguous evidence that non-periodic noise, if present,
significantly reduce accuracy of orbital parameters obtained from
high-precision polarization data for the low-inclination systems.
Using the values of polarization variability amplitude, we estimated
the mass-loss rate for the whole system to be
(dM/dt=2.46x10-7±2.47x10-8M_☉/yr. The direction of the
binary system rotation on the plane of the sky is clockwise. Our
observations of HD 165052 neighbour stars revealed complex behaviour
of interstellar polarization in the cluster NGC 6530.
Description:
Polarimetric data of HD 165052: MJD, Stokes q in B passband, Stokes u
in B Passband, error in B passband, Stokes q in V passband, Stokes u
in V Passband, error in V passband, Stokes q in R passband, Stokes u
in R Passband, error in R passband.
Objects:
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RA (2000) DE Designation(s)
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18 05 10.55 -24 23 54.8 HD 165052 = TIC 407454643
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
stokesub.dat 32 68 Polarimetric data of HD 165052,
Stokes u in B passband
stokesur.dat 32 68 Polarimetric data of HD 165052,
Stokes u in R passband
stokesuv.dat 32 68 Polarimetric data of HD 165052,
Stokes u in V passband
stokesqb.dat 32 68 Polarimetric data of HD 165052,
Stokes q in B passband
stokesqr.dat 32 68 Polarimetric data of HD 165052,
Stokes q in R passband
stokesqv.dat 32 68 Polarimetric data of HD 165052,
Stokes q in v passband
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See also:
J/A+A/591/A92 : BVR polarimetry of HD 48099 (Berdyugin+, 2016)
J/A+A/611/A69 : B, V and R band polarimetry of lambda Tau (Berdyugin+, 2018)
J/A+A/670/A176 : B, V and R band polarimetry of AO Cas (Abdul Qadir+, 2023)
J/A+A/677/A75 : B, V and R band polarimetry of DH Cep (Abdul Qadir+, 2023)
Byte-by-byte Description of file: stokesqb.dat stokesqr.dat stokesqv.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d MJD Modified Julian date
16- 21 F6.4 --- q Stokes q parameter in Band
23- 28 F6.4 --- e_q Stokes q parameter in Band error
30 A1 --- --- [q]
32 A1 --- Band [BVR] Band
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Byte-by-byte Description of file: stokesub.dat stokesur.dat stokesuv.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d MJD Modified Julian date
15- 21 F7.4 --- u Stokes u parameter in Band
23- 28 F6.4 --- e_u Stokes u parameter in Band error
30 A1 --- --- [u]
32 A1 --- Band [BVR] Band
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Acknowledgements:
Yasir Abdul Qadir, yasir.abdulqadir(at)utu.fi
References:
Berdyugin et al., Paper I 2016A&A...591A..92B 2016A&A...591A..92B, Cat. J/A+A/591/92
Berdyugin et al., Paper II 2018A&A...611A..69B 2018A&A...611A..69B, Cat. J/A+A/611/69
Abdul Qadir et al., Paper III 2023A&A...670A.176A 2023A&A...670A.176A, Cat. J/A+A/670/A176
Abdul Qadir et al., Paper IV 2023A&A...677A..75A 2023A&A...677A..75A, Cat. J/A+A/677/A75
(End) Patricia Vannier [CDS] 02-Apr-2025