J/AJ/146/58 Eclipse timings for NGC 6819-259 (Jeffries+, 2013)
WOCS 40007: a detached eclipsing binary near the turnoff of the open cluster
NGC 6819.
Jeffries M.W.Jr, Sandquist E.L., Mathieu R.D., Geller A.M., Orosz J.A.,
Milliman K.E., Brewer L.N., Platais I., Brogaard K., Grundahl F.,
Frandsen S., Dotter A., Stello D.
<Astron. J., 146, 58 (2013)>
=2013AJ....146...58J 2013AJ....146...58J
ADC_Keywords: Binaries, eclipsing
Keywords: binaries: eclipsing - binaries: spectroscopic -
open clusters and associations: individual: NGC 6819 -
stars: evolution - techniques: photometric - techniques: spectroscopic
Abstract:
We analyze extensive BVRcIctime-series photometry and
radial-velocity measurements for WOCS 40007 (Auner 259; KIC 5113053),
a double-lined detached eclipsing binary and a member of the open
cluster NGC 6819. Utilizing photometric observations from the 1m
telescope at Mount Laguna Observatory and spectra from the WIYN 3.5m
telescope, we measure precise and accurate masses (∼1.6% uncertainty)
and radii (∼0.5%) for the binary components. In addition, we discover
a third star orbiting the binary with a period greater than 3000days
using radial velocities and Kepler eclipse timings. Because the stars
in the eclipsing binary are near the cluster turnoff, they are
evolving rapidly in size and are sensitive to age. With a metallicity
of [Fe/H]=+0.09 ±0.03, we find the age of NGC 6819 to be about
2.4Gyr from color-magnitude diagram (CMD) isochrone fitting and
3.1±0.4Gyr by analyzing the mass-radius (M-R) data for this binary.
The M-R age is above previous determinations for this cluster, but
consistent within 1σ uncertainties. When the M-R data for the
primary star of the additional cluster binary WOCS 23009 is included,
the weighted age estimate drops to 2.5±0.2Gyr, with a systematic
uncertainty of at least 0.2Gyr. The age difference between our CMD and
M-R findings may be the result of systematic error in the metallicity
or helium abundance used in models, or due to slight radius inflation
of one or both stars in the WOCS 40007 binary.
Description:
We obtained CCD images in B, V, Rc, and Ic of NGC 6819 using the 1m
telescope at Mount Laguna Observatory (MLO). Our photometric dataset
consists of 46 nights between 2001 March and 2011 September, with the
majority from 2008, 2010, and 2011.
Spectroscopic observations were obtained as part of the WIYN Open
Cluster Study (WOCS; Mathieu, 2000ASPC..198..517M 2000ASPC..198..517M). We use the
observations of Hole et al. (2009, cat. J/AJ/138/159), who presented
high-precision RVs for 1207 stars in NGC 6819, and more recent WOCS
spectroscopic observations of Milliman et al. (2013, AJ, in press).
WOCS uses the WIYN 3.5m telescope on Kitt Peak and the Hydra
multi-object spectrograph (MOS) instrument, which is a fiber-fed
spectrograph.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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19 41 33.93 +40 13 00.4 KIC 5113053 = [HGM2009b] WOCS 040007 (P=3.185)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 50 558 Eclipse timings for WOCS 40007
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2010)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/AJ/142/160 : Kepler Mission. II. 2165 eclipsing binaries (Slawson+, 2011)
J/ApJ/729/L10 : KIC stars properties in NGC 6791 and NGC 6819 (Basu+, 2011)
J/AJ/138/159 : NGC 6819 stellar radial-velocity and photometry (Hole+, 2009)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d BJD Barycentric Julian Date; BJD-2450000
12- 18 F7.5 d e_BJD The 1σ uncertainty in BJD
20 A1 --- Type [PS] Eclipse type (P=primary, S=secondary)
22- 50 A29 --- Note Additional notes (1)
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Note (1): We used long-cadence data from quarters 1-13 (excluding quarters 6
and 10) of the Kepler data.
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History:
From electronic version of the journal
References:
Sandquist et al., Paper I, 2013ApJ...762...58S 2013ApJ...762...58S
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 03-Jul-2014