J/AJ/158/106 Eclipsing binaries RVs from APOGEE spectra (Cunningham+, 2019)
APOGEE/Kepler overlap yields orbital solutions for a variety of eclipsing
binaries.
Cunningham J.M.C., Rawls M.L., Windemuth D., Ali A., Jackiewicz J.,
Agol E., Stassun K.G.
<Astron. J., 158, 106-106 (2019)>
=2019AJ....158..106C 2019AJ....158..106C (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Radial velocities ; Magnitudes
Keywords: binaries: eclipsing
Abstract:
Spectroscopic eclipsing binaries (SEBs) are fundamental benchmarks in
stellar astrophysics and today are observed in breathtaking detail by
missions like the Transiting Exoplanet Survey Satellite (TESS), Kepler,
and Apache Point Observatory Galactic Evolution Experiment (APOGEE).
We develop a methodology for simultaneous analysis of high-precision
Kepler light curves and high-resolution near-infrared spectra from APOGEE
and present orbital solutions and evolutionary histories for a subset of
SEBs within this overlap. Radial velocities extracted from APOGEE spectra
using the broadening function (BF) technique are combined with Kepler
light curves and to yield binary orbital solutions. The BF approach yields
more precise radial velocities than the standard cross-correlation
function, which in turn yields more precise orbital parameters and enables
the identification of tertiary stars. The orbital periods of these seven
SEBs range from 4 to 40 days. Four of the systems (KIC 5285607,
KIC 6864859, KIC 6778289, and KIC 4285087) are well-detached binaries.
The remaining three systems have apparent tertiary companions, but each
exhibit two eclipses along with at least one spectroscopically varying
component (KIC 6449358, KIC 6131659, and KIC 6781535). Gaia distances are
available for four targets which we use to estimate temperatures of both
members of these SEBs. We explore evolutionary histories in H-R diagram
space and estimate ages for this subset of our sample. Finally, we consider
the implications for the formation pathways of close binary systems via
interactions with tertiary companions. Our methodology combined with
the era of big data and observation overlap opens up the possibility of
discovering and analyzing large numbers of diverse SEBs, including those
with high flux ratios and those in triple systems.
Description:
We use the following criteria and filters to arrive at a candidate
sample of promising SEBs in the APOGEE/Kepler overlap. We begin with
the Kepler EB catalog compiled by Kirk et al. (2016, J/AJ/151/68). From
this catalog we select targets that have both their primary and secondary
eclipses observed by Kepler; this limits our selection to binaries with
inclinations close to 90°. We further require the light curve to be
semi- or well-detached, with the morphology parameter significantly less
than 1. Next, a luminosity limit of H<14 magnitudes was imposed, as fainter
targets are unlikely to have H-band APOGEE spectra with a sufficiently
high signal-to-noise ratio (S/N). We also require the targets to have
multiple cross-correlation function (CCF) peaks from the APOGEE pipeline
(Nidever et al. 2015AJ....150..173N 2015AJ....150..173N) visible by eye in one epoch. Finally,
the binaries must have been observed by APOGEE at least three times, and
thus have at least three apVisit spectra, with no quality flags present.
Taken together, these criteria result in 33 candidates, which are listed
in Table 1, plus one additional candidate that has already been analyzed
(Rawls et al. 2016ApJ...818..108R 2016ApJ...818..108R).
The standard observing mode for APOGEE spectra has a total exposure time
of roughly three hours, which is usually collected over a series of visits
on different days. The visits are then combined into one spectrum per
target (an apStar spectrum). We instead utilize individual visit spectra
(apVisit), which are identified with their plate ID, date (MJD), and
fiber ID. These may be retrieved from the SDSS Science Archive Server
search tool with a simple search by APOGEE ID. We continuum normalize
the visit spectra and then de-spike them to remove erroneous spectral
features due to tellurics. De-spiking consists of identifying outliers
above or below the continuum by 0.7 or 3 times the standard deviation
of the normalized flux, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 118 34 Promising SEBs observed by APOGEE and Kepler,
sorted by Kepler magnitude (Kp)
table4.dat 59 115 Measured RV from APOGEE spectra
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/A+A/387/850 : Radial velocities of eclipsing binaries (Imbert, 2002)
J/AJ/151/68 : Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)
J/AJ/154/105 : Parameters of 529 Kepler eclipsing binaries
(Kjurkchieva+, 2017)
J/AJ/154/216 : Radial velocities of 41 Kepler eclipsing binaries
(Matson+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- KIC [2305543/10206340] Kepler Input Catalog number
10- 27 A18 --- APOGEE APOGEE identifier (2MHHMMSSss+DDMMSSs)
29- 30 I2 --- Nvis [2/27] Number of visits
32- 36 F5.2 mag Kpmag [10.08/15.71] Kepler magnitude
38- 43 F6.2 d Porb [0.56/171.28] Orbital period
45- 50 F6.4 --- Depth [0.001/0.4156] Fractional depth of secondary
eclipse
52- 55 F4.2 --- Morph [0/0.62] Morphology parameter
57- 75 A19 --- Ref Reference
77- 95 A19 --- Bibcode Bibcode of the reference
97-118 A22 --- Note Note (1)
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Note (1): The notes indicate why we choose to exclude the other systems at this
time. Several are being investigated by the Kepler APOGEE EB Working Group
(WG), some have only three APOGEE visits, which would make a good RV curve
solution challenging without additional spectra, some have low S/Ns, one shows
significant ellipsoidal variations, which are not included in our photometric
model, and two remain good candidates for future analyses.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [KIC]
5- 11 I7 --- KIC [4285087/6864859] Kepler Input Catalog number
13- 25 F13.5 d Time Barycentric Julian Date
27- 31 F5.3 --- Phase [0.028/0.987] Orbital phase
33- 39 F7.3 km/s RV1 [-24.927/158.478]? Primary radial velocity
41- 45 F5.3 km/s e_RV1 [0.04/0.354]? Uncertainty in RV1
47- 53 F7.3 km/s RV2 [-37.069/167.332]? Secondary radial velocity
55- 59 F5.3 km/s e_RV2 [0.041/0.204]? Uncertainty in RV2
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 17-Oct-2019