J/AJ/149/168 Differential VRI photometry of HI Dra (Papageorgiou+, 2015)
Absolute parameters and physical nature of the low-amplitude contact binary
HI Draconis.
Papageorgiou A., Christopoulou P.-E.
<Astron. J., 149, 168 (2015)>
=2015AJ....149..168P 2015AJ....149..168P
ADC_Keywords: Binaries, eclipsing ; Photometry, VRI ; Photometry, CCD
Keywords: binaries: eclipsing - stars: fundamental parameters -
stars: individual: HI Dra
Abstract:
We present a detailed investigation of the low-amplitude contact
binary HI Dra based on the new VRcIc CCD photometric light curves
(LCs) combined with published radial velocity (RV) curves. Our
completely covered LCs were analyzed using PHOEBE and revealed that HI
Dra is an overcontact binary with low fill-out factor f=24±4(%) and
temperature difference between the components of 330K. Two spotted
models are proposed to explain the LC asymmetry, between which the A
subtype of W UMa type eclipsing systems, with a cool spot on the less
massive and cooler component, proves to be more plausible on
evolutionary grounds. The results and stability of the solutions were
explored by heuristic scan and parameter perturbation to provide a
consistent and reliable set of parameters and their errors. Our
photometric modeling and RV curve solution give the following absolute
parameters of the hot and cool components, respectively:
Mh=1.72±0.08M☉ and Mc=0.43±0.02M☉,
Rh=1.98±0.03R☉ and Rc=1.08±0.02R☉, and
Lh=9.6±0.1L☉ and Lc=2.4±0.1L☉. Based on these
results the initial masses of the progenitors (1.11±0.03M☉ and
2.25±0.07M☉, respectively) and a rough estimate of the age of
the system of 2.4Gyr are discussed.
Description:
New multiwavelength CCD photometric observations were carried out on
2011 October 6, 12, and 13 in the V, Ic passbands, on 2012 June 1,
2, 3, and 6 in the VRcIc passbands, and on 2013 October 22 in the
Ic passband, with the 35.5cm f/6.3 Schmidt-Cassegrain telescope at
the University of Patras Observatory "Mythodea." This telescope is
equipped with an SBIG ST-10 XME CCD camera that has 2184*1472pixels.
The size of each pixel is 0.57'', resulting in an effective field of
view of 20*14arcmin. The standard Johnson-Cousins-Bessel set of
BVRcIc was mounted. The typical integration times were 35-55s for
the V band, 30s for the Rc band, and 40-55s for the Ic band.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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18 33 24.36 +58 42 23.4 V* HI Dra = HIP 90972 (P=0.597418)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 65 636 VRcIc observational data for the eclipsing
binary HI Dra
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See also:
J/AJ/148/126 : Light curves of four overcontact binaries (Caliskan+, 2014)
J/AJ/146/157 : Differential BVRI photometry of FI Boo (Christopoulou+, 2013)
J/AJ/146/70 : Spectroscopy of W UMa-type binary stars (Rucinski+, 2013)
J/AJ/144/149 : CCD photometry of the W UMa type TY Boo (Christopoulou+, 2012)
J/AJ/143/30 : CCD photometry of V380 Cas (Christopoulou+, 2012)
J/AJ/142/99 : BVRI observations of TZ Boo (Christopoulou+, 2011)
J/AJ/137/3655 : Radial velocities of 8 close binaries (Pribulla+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD-V ? Heliocentric Julian Date of V-band observation
15- 21 F7.4 mag DVmag ? Delta V-band magnitude (1)
23- 35 F13.5 d HJD-R ? Heliocentric Julian Date of Rc-band observation
37- 43 F7.4 mag DRmag ? Delta Rc-band magnitude (1)
45- 57 F13.5 d HJD-I Heliocentric Julian Date of Ic-band observation
59- 65 F7.4 mag DImag Delta Ic-band magnitude (1)
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Note (1): Between HI Dra and comparison star (TYC 03917-1556-1).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 29-May-2015