J/A+A/615/A79 KOINet. Study of exoplanet systems via TTVs (von Essen+, 2018)
Kepler Object of Interest Network.
I. First results combining ground- and space-based observations of Kepler
systems with transit timing variations.
von Essen C., Ofir A., Dreizler S., Agol E., Freudenthal J., Hernandez J.,
Wedemeyer S., Parkash V., Deeg H.J., Hoyer S., Morris B.M., Becker A.C.,
Sun L., Gu S.H., Herrero E., Tal-Or L., Poppenhaeger K., Mallonn M.,
Albrecht S., Khalafinejad S., Boumis P., Delgado-Correal C., Fabrycky D.C.,
Janulis R., Lalitha S., Liakos A., Mikolaitis S., Moyano D'Angelo M.L.,
Sokov E., Pakstiene E., Popov A., Krushinsky V., Ribas I.,
Rodriguez M.M.S., Rusov S., Sokova I., Tautvaisiene G., Wang X.
<Astron. Astrophys., 615, A79 (2018)>
=2018A&A...615A..79V 2018A&A...615A..79V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry
Keywords: instrumentation: photometers - methods: data analysis -
techniques: photometric -
planets and satellites: dynamical evolution and stability
Abstract:
During its four years of photometric observations, the Kepler space
telescope detected thousands of exoplanets and exoplanet candidates.
One of Kepler's greatest heritages has been the confirmation and
characterization of hundreds of multi-planet systems via transit
timing variations (TTVs). However, there are many interesting
candidate systems displaying TTVs on such long timescales that the
existing Kepler observations are of insufficient length to confirm and
characterize them by means of this technique. To continue with
Kepler's unique work, we have organized the "Kepler Object of Interest
Network" (KOINet), a multi-site network formed of several telescopes
located throughout America, Europe, and Asia. The goals of KOINet are
to complete the TTV curves of systems where Kepler did not cover the
interaction timescales well, to dynamically prove that some candidates
are true planets (or not), to dynamically measure the masses and bulk
densities of some planets, to find evidence for non-transiting planets
in some of the systems, to extend Kepler's baseline adding new data
with the main purpose of improving current models of TTVs, and to
build a platform that can observe almost anywhere on the northern
hemisphere, at almost any time. KOINet has been operational since
March 2014. Here we show some promising first results obtained from
analyzing seven primary transits of KOI-0410.01, KOI-0525.01,
KOI-0760.01, and KOI-0902.01, in addition to the Kepler data acquired
during the first and second observing seasons of KOINet. While
carefully choosing the targets we set demanding constraints on timing
precision (at least 1 min) and photometric precision (as good as one
part per thousand) that were achieved by means of our observing
strategies and data analysis techniques. For KOI-0410.01, new transit
data revealed a turnover of its TTVs. We carried out an in-depth study
of the system, which is identified in the NASA Data Validation Report
as a false positive. Among others, we investigated a gravitationally
bound hierarchical triple star system and a planet-star system. While
the simultaneous transit fitting of ground- and space-based data
allowed for a planet solution, we could not fully reject the
three-star scenario. New data, already scheduled in the upcoming 2018
observing season, will set tighter constraints on the nature of the
system.
Description:
All our observations were carried out using R-band filter. We provide
the differential photometry with varying reference stars for each
observation together with the used detrending components. We provide
four transits of KOI-0410.01, and one transit of KOI-0902.01,
KOI-0525.01, and KOI-0760.01, respectively. The telescope
nomenclature, in agreement with the names of the files, is the
following:
IAC0.8: IAC80 telescope (0.8m), Instituto de Astrofisica de
Canarias, Spain.
ARC3.5: Apache Point Observatory (3.5 m), USA.
NOT2.5: Nordic Optical Telescope (2.5 m), Spain.
YO2.4: Yunnan Observatories (2.4 m), PR China.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
19 28 59.52 +40 41 45.7 KOI-0410 = KIC 5449777
20 03 37.86 +45 27 28.3 KOI-0525 = KIC 9119458
19 28 40.09 +48 43 39.3 KOI-0760 = KIC 11138155
19 11 24.57 +43 53 52.9 KOI-0902 = KIC 8018547
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 99 7 Most relevant parameters obtained from our
observations
0410-01a.dat 95 178 KOI-0410.01 light curve on 2014.10.12 with NOT2.5
0410-01b.dat 95 127 KOI-0410.01 light curve on 2014.11.03 with YO2.4
0410-01c.dat 95 667 KOI-0410.01 light curve on 2015.07.06 with CAHA2.2
0410-01d.dat 95 142 KOI-0410.01 light curve on 2015.07.06 with NOT2.5
0525-01.dat 95 135 KOI-0525.01 light curve on 2014.08.28 with ARC3.5
0760-01.dat 95 275 KOI-0760.01 light curve on 2014.10.03 with NOT2.5
0902-01.dat 95 114 KOI-0902.01 light curve on 2014.06.24 with IAC0.8
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 "date" Date Beginning of the local night
12- 20 A9 --- Tel Telescope performing the observations (1)
22- 32 A11 --- Name Name of the observed KOI (KOI-NNNN.01)
34- 36 F3.1 10-3 sigmares Standard deviation of the residual light
curves in parts per thousand (ppt)
38- 40 I3 --- N Number of data points per light curve
42- 44 I3 s CAD Average cadence
46- 49 F4.2 h Ttot Total observing time
51- 54 F4.2 --- bAirmass Minimum value for airmass range
55 A1 --- --- [,]
56- 59 F4.2 --- BAirmass Maximun value for airmass range
61- 65 A5 --- TC Transit coverage (2)
67- 79 F13.5 d TTVs Derived mid-transit time, in BJD(TDB)
81- 86 F6.4 d e_TTVs rms uncertainty (1sigma) on TTVs
88- 99 A12 --- FileName Name of the table with photometry
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Note (1): Instruments as follows:
ARC 3.5m = The Apache Point Observatory, located in New Mexico, United States
of America, hosts the Astrophysical Research Consortium 3.5-m
telescope. The data were collected using Agile. The ARC 3.5m
observed one transit of KOI-0525.01, our lower-limit KOI for
transit depth. Nonetheless, during the first observing seasons we
collected a substantial amount of data that will be presented
in future work.
NOT 2.5m = The Nordic Optical Telescope is located at the Roque de los
Muchachos Observatory in La Palma, Spain, and belongs to the
Nordic Optical Telescope Scientific Association, governed and
funded by Scandinavian countries. In this work we present
observations of KOI-0760.01 and KOI-0410.01.
CAHA 2.2m = The 2.2m Calar Alto Telescope is located in Almeria, Spain. We
observed KOI-0410.01 using the Calar Alto Faint Object
Spectrograph in its photometric mode.
IAC 0.8m = The IAC80 telescope is located at the Observatorio del Teide, in
the Canary Islands, Spain. We observed half a transit of
KOI-0902.01 for about 7h.
YO 2.4m = The Lijiang 2.4m telescope is located at the Yunnan Observatories
in Kunming, PR China. In this work we present observations of
KOI-0410.01.
Note (2): The letter code specifying the transit coverage during each
observation is as follows:
o = out of transit, before ingress
I = ingress
B = flat bottom
E = egress
O = out of transit, after egress
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Byte-by-byte Description of file: 0*.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 F20.12 d BJD Barycentric Julian date in barycentric
dynamical time
22- 45 E24.19 --- Flux Raw flux
47- 70 E24.19 --- e_Flux Flux error scaled by the standard deviation
and the β value
72- 95 E24.19 --- Fluxd Detrended flux
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Acknowledgements:
Carolina von Essen, cessen(at)phys.au.dk
(End) Patricia Vannier [CDS] 04-Sep-2018