J/AJ/149/146 UBV(RI)c differential light curves of HR Boo (Samec+, 2015)
First precision light curve analysis of the neglected extreme mass ratio
solar-type binary HR Bootis.
Samec R.G., Benkendorf B., Dignan J.B., Robb R., Kring J., Faulkner D.R.
<Astron. J., 149, 146 (2015)>
=2015AJ....149..146S 2015AJ....149..146S
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI
Keywords: binaries: close - binaries: eclipsing - stars: evolution -
stars: individual: HR Boo
Abstract:
HR Bootis is a neglected binary that is found to be a solar-type (G2V)
extreme mass ratio binary (EMRB). It was discovered by Hanley &
Shapley in 1940. Surprisingly, little has been published in the
intervening years. In 1999 it was characterized by a 0.31587day
orbital period. Since that time it has been observed by various
observers who have determined ∼20 timings of minimum light over the
past ∼15000 orbits. Our observations in 2012 represent the first
precision curves in the BVRcIcJohnson-Cousins wavelength bands.
The light curves have rather low amplitudes, averaging some 0.5
magnitudes, yet they exhibit total eclipses, which is typical of the
rare group of solar-type EMRBs. An improved linear ephemeris was
computed along with a quadratic ephemeris showing a decaying orbit,
which indicates magnetic breaking may be occurring. The light curve
solution reveals that HR Boo is a contact system with a somewhat low
21% Roche-lobe fill-out but a mass ratio of q=4.09 (0.2444), which
defines it as an EMRB. Two spots, both hot, were allowed to iterate to
fit the light curve asymmetries. Their radii are 32° and 16°.
Both are high-latitude polar spots indicative of strong magnetic
activity. The shallow contact yet nearly equal component temperatures
makes it an unusual addition to this group.
Description:
This system was observed as part of our student/professional
collaborative studies of interacting binaries from data taken from
NURO observations (National Undergraduate Research Observatory, Lowell
Observatory, Flagstaff, AZ). The observations were taken by Dr. Ronald
Samec, Barry Beckendorf, and James B. Dignan. Reduction and analyses
were mostly done by James Kring and Dr. Samec. The UBVRcIc light
curves were taken with the Lowell 0.81m reflector in Flagstaff on 2012
May 6, 7, and 10 with CRYOTIGER cooled (-100°C) 2048*2048 NASACAM
and standard Johnson-Cousins UBVRcIc filters.
Individual observations included 48 in the U filter (Table 2), 111 in
B (Table 3), 115 in V (Table 4), 113 in Rc (Table 5), and 112 in
Ic (Table 6). The probable error of a single observation was 5mmag
in U and B, 6mmag in V, and 7mmag in Rc and Ic.
The comparison star, GSC 1484 0665 [α(2000)=14h48m33.0s,
δ(2000)=+21°44'01'' Guide 9], V=13.2-13.8, J-K=0.42 and
check star, GSC 1484 0549 [α(2000)=14h48m48.3580s,
δ(2000)=21°46'47.020'', Guide 9], V=13.82, J-K=0.52, were
chosen in the same 15' field.
Objects:
---------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
---------------------------------------------------------------
14 48 33.02 +21 44 01.1 V* HR Boo = NSV 6813 (P=0.3160431)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 13 48 ΔU magnitude photometry of HR Boo
table3.dat 13 111 ΔB magnitude photometry of HR Boo
table4.dat 13 115 ΔV Magnitude Photometry of HR Boo
table5.dat 13 113 ΔRc magnitude photometry of HR Boo
table6.dat 13 112 ΔIc magnitude photometry of HR Boo
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AJ/149/90 : UBVRI light curves of GSC 3208-1986 (Samec+, 2015)
J/AJ/149/48 : BVRI light curves of ZZ Eri (Samec+, 2015)
J/AJ/147/3 : BV(RI)c light curves of V2421 Cyg (Samec+, 2014)
J/AJ/145/14 : BV(RI)c light curves of V1043 Cas (Samec+, 2013)
J/PASP/124/693 : HO Psc UBV(RI)c light curves (Samec+, 2012)
J/AJ/142/117 : UBVRcIc differential photometry of V1853 Ori (Samec+, 2011)
J/other/IBVS/5918 : Minima and maxima of 452 variables (Hubscher+, 2010)
J/other/IBVS/5863 : 79th Name-List of Variable Stars (Kazarovets+, 2008)
J/AJ/131/621 : Catalog of 1022 bright contact binary stars (Gettel+, 2006)
Byte-by-byte Description of file: table[23456].dat
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Bytes Format Units Label Explanations
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1- 6 F6.4 mag Dmag [0.5/1.1] Johnson-Cousins instrumental Δ
magnitude (1)
8- 13 F6.4 d HJD Heliocentric Julian Date (HJD-2455800)
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Note (1): In the sense of variable minus comparison star (GSC 1484-0665).
The probable error of a single observation was 5mmag in U and B, 6mmag in
V, and 7mmag in Rc and Ic.
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 11-May-2015