J/AJ/145/43 CASE. V. Three eclipsing binaries in M4 (Kaluzny+, 2013)
The Cluster AgeS Experiment (CASE). V. Analysis of three eclipsing binaries in
the globular cluster M4.
Kaluzny J., Thompson I.B., Rozyczka M., Dotter A., Krzeminski W., Pych W.,
Rucinski S.M., Burley G.S., Shectman S.A.
<Astron. J., 145, 43 (2013)>
=2013AJ....145...43K 2013AJ....145...43K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Binaries, eclipsing ; Radial velocities
Keywords: binaries: close - stars: individual (V65-M4,V66-M4,V69-M4) -
binaries: spectroscopic - globular clusters: individual: M4
Abstract:
We use photometric and spectroscopic observations of the eclipsing
binaries V65, V66, and V69 in the field of the globular cluster M4 to
derive masses, radii, and luminosities of their components. The
orbital periods of these systems are 2.29, 8.11, and 48.19days,
respectively. The measured masses of the primary and secondary
components (Mp and Ms) are 0.8035±0.0086 and
0.6050±0.0044M☉ for V65, 0.7842±0.0045 and
0.7443±0.0042M☉ for V66, and 0.7665±0.0053 and
0.7278±0/0048M☉ for V69. The measured radii (Rp and Rs)
are 1.147±0.010 and 0.6110 ± 0.0092R☉ for V66,
0.9347±0.0048 and 0.8298±0.0053R☉ for V66, and
0.8655±0.0097 and 0.8074±0.0080R☉ for V69. The orbits of V65
and V66 are circular, whereas that of V69 has an eccentricity of 0.38.
Based on systemic velocities and relative proper motions, we show that
all three systems are members of the cluster. We find that the
distance to M4 is 1.82±0.04kpc-in good agreement with recent
estimates based on entirely different methods. We compare the absolute
parameters of V66 and V69 with two sets of theoretical isochrones in
mass-radius and mass-luminosity diagrams, and for assumed
[Fe/H]=-1.20, [α/Fe]=0.4, and Y=0.25 we find the most probable
age of M4 to be between 11.2 and 11.3Gyr. Color-magnitude diagram
(CMD) fitting with the same parameters yields an age close to, or
slightly in excess of, 12Gyr. However, considering the sources of
uncertainty involved in CMD fitting, these two methods of age
determination are not discrepant. Age and distance determinations can
be further improved when infrared eclipse photometry is obtained.
Description:
Our survey for eclipsing binaries in M4 began in 1995 July with a
two-week observational campaign at Cerro Tololo Inter-American
Observatory (CTIO). We monitored the cluster in the B and V bands,
using the 2K2 TEK2 camera attached to the 0.9m telescope. A single
eclipse of V66 was detected, occurring on UT 1995 July 18. The survey
continued on the 1.0m Swope telescope at the Las Campanas Observatory
(LCO) using five different CCD cameras (Ford, TEK3, SITe1, SITe2, and
SITe3) over several seasons during the period 1996-2009. Most of the
observations were obtained with the SITe3 camera, with a plate scale
of 0.435arcsec/pixel and a field size of 14.8*22.8arcmin2. Some
early results from this survey were presented in Kaluzny et al.
(1997AJ....113.2219K 1997AJ....113.2219K). The first eclipses of V65 and V69 were detected
on UT 1996 April 16 and UT 1996 April 21, respectively. A part of a
secondary eclipse of V69 was observed on UT 1998 August 17. From 1998
until 2009 we also observed our targets with the 2.5m du Pont
telescope at LCO equipped with the TEK5 2K2 camera with a plate
scale of 0.259arcsec/pixel. Between 2001 and 2009, several eclipses
were covered for V65 and V69, and some out-of-eclipse data were
collected for V69. In all observing runs, on each telescope, the same
B and V filters were used.
The spectra were taken with the MIKE echelle spectrograph on the
Magellan Baade and Clay 6.5m telescopes, using a 0.7" slit, which
provided a resolution R∼40000.
Objects:
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RA (2000) DE Designation(s) (Period)
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16 23 28.39 -26 30 21.9 V65 = 2MASS J16232838-2630216 (P=2.29)
16 23 32.23 -26 31 41.3 V66 = Cl* NGC 6121 MKTWD 11657 (P=8.11)
16 23 58.08 -26 37 18.9 V69 = UGCS J162358.09-263719.0 (P=48.19)
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 37 8 Times of minima for V65
table2.dat 37 14 Times of minima for V66
table3.dat 37 3 Times of minima for V69
table7.dat 38 41 Velocity observations of V65
table8.dat 38 21 Velocity observations of V66
table9.dat 38 30 Velocity observations of V69
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AJ/136/400 : Cl* NGC 6397 SAW V32 V light curve (Kaluzny+, 2008)
J/ApJ/443/124 : Radial Velocities of Stars in M4 (Peterson+ 1995)
Byte-by-byte Description of file: table[123].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.1 --- E Eclipse (1)
8 A1 --- f_E [a] The orbit is eccentric, and the secondary
minimum occurs at phase 0.6086052(±0.0000077)
10- 20 F11.5 d HJD Heliocentric Julian Date (HJD-2400000)
22- 28 F7.5 d e_HJD 1σ uncertainty in HJD
30- 37 F8.5 d O-C The (O-C) residual
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Note (1): Eclipses listed twice were observed in both B and V.
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Byte-by-byte Description of file: table[789].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.5 d HJD Heliocentric Julian Date at mid-exposure
(HJD-2450000)
12- 17 F6.2 km/s RV1 Radial velocity of the primary component
19- 24 F6.2 km/s RV2 Radial velocity of the secondary component
26- 30 F5.2 km/s RV3 ? Radial velocity of the contaminating star (1)
32- 38 F7.4 --- Phase Orbital phase (2)
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Note (1): Only for V65 (Table7; see Section 3 for more details).
Note (2): Calculated according to the ephemerides given by Equations (1):
HJDmin(V65)=2449905.49577(43)+2.29304564(26)*E;
HJDmin(V66)=2449900.41965(26)+8.11130346(85)*E;
HJDmin(V69)=2450048.34890(14)+48.1882687(6)*E.
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History:
From electronic version of the journal
References:
Kaluzny et al., Paper I, 2007AJ....133.2457K 2007AJ....133.2457K
Kaluzny et al., Paper II, 2007AJ....134..541K 2007AJ....134..541K
Kaluzny et al., Paper III, 2008AJ....136..400K 2008AJ....136..400K, cat. J/AJ/136/400
Thompson et al., Paper IV, 2010AJ....139..329T 2010AJ....139..329T
(End) Sylvain Guehenneux [CDS] 21-Mar-2014