J/ApJ/753/101 Kepler eclipse timings of KIC 9472174 (Barlow+, 2012)
The romer delay and mass ratio of the sdB+dM binary 2M 1938+4603 from
Kepler eclipse timings.
Barlow B.N., Wade R.A., Liss S.E.
<Astrophys. J., 753, 101 (2012)>
=2012ApJ...753..101B 2012ApJ...753..101B
ADC_Keywords: Binaries, eclipsing ; Photometry
Keywords: binaries: close; binaries: eclipsing; stars: individual: 2M 1938+4603;
subdwarfs; techniques: photometric
Abstract:
The eclipsing binary system 2M 1938+4603 consists of a pulsating hot
subdwarf B star and a cool M dwarf companion in an effectively
circular three-hour orbit. The light curve shows both primary and
secondary eclipses, along with a strong reflection effect from the
cool companion. Here, we present constraints on the component masses
and eccentricity derived from the Romer delay of the secondary
eclipse. Using six months of publicly available Kepler photometry
obtained in short-cadence mode, we fit model profiles to the primary
and secondary eclipses to measure their centroid values. We find that
the secondary eclipse arrives on average 2.06±0.12s after the
midpoint between primary eclipses. Under the assumption of a circular
orbit, we calculate from this time delay a mass ratio of
q=0.2691±0.0018 and individual masses of Msd=0.372±0.024M☉
and Mc=0.1002±0.0065M☉ for the sdB and M dwarf,
respectively. These results differ slightly from those of a previously
published light-curve modeling solution; this difference, however, may
be reconciled with a very small eccentricity,
ecosω~0.00004. We also report a decrease in the orbital
period of {dot}P=(-1.23±0.07)x10-10.
Description:
In 2009 May, and from 2010 March to 2010 September, Kepler observed
1436 orbital cycles of 2M 1938 using short-cadence observations. In
this operating mode, nine 6.02s exposures, each with a readout time of
0.52s, are summed into memory to produce an image every 58.85s (92%
duty cycle). We downloaded the public Q0, Q5, and Q6 light curves from
the Kepler data archive. We converted the time stamps, given as the
Barycentric Kepler Julian Date and accurate to ±0.05s, to the
Barycentric Julian Date.
Objects:
------------------------------------------------------------------------
RA (2000) DE Designation(s) (Period in days)
------------------------------------------------------------------------
19 38 32.61 +46 03 59.2 2M 1938+4603 = KIC 9472174 (P=0.125765251)
------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 18 1513 Dates of primary eclipse minimum
table2.dat 18 1504 Dates of secondary eclipse minimum
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/PASP/124/1279 : Q3 Kepler's combined photometry (Christiansen+, 2012)
J/AJ/143/101 : Kepler B-star variables classification (McNamara+, 2012)
J/A+A/529/A89 : Kepler satellite variability study (Debosscher+, 2011)
J/AJ/142/160 : Kepler Mission. II. 2165 eclipsing binaries (Slawson+, 2011)
J/MNRAS/413/1581 : Candidate subdwarfs and white dwarfs (Gontcharov+, 2011)
J/MNRAS/409/1470 : Kepler compact pulsator candidates (Ostensen+, 2010)
J/MNRAS/408/L51 : 2M1938+4603 (KIC 9472174) eclipses (Ostensen+, 2010)
J/AcA/59/33 : ASAS variable stars in Kepler field. (Pigulski+, 2009)
http://archive.stsci.edu/kepler : : MAST Kepler home page
Byte-by-byte Description of file: table[12].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.5 d BJD Barycentric Julian Date eclipse minimum
(BJD-2450000)
12- 18 F7.5 d e_BJD Error in BJD
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Feb-2014