J/A+A/657/A102 Transit events of 4 extrasolar planets (Mallonn+, 2022)
Detection capability of ground-based meter-sized telescopes for shallow
exoplanet transits.
Mallonn M., Poppenhaeger K., Granzer T., Weber M., Strassmeier K.G.
<Astron. Astrophys. 657, A102 (2022)>
=2022A&A...657A.102M 2022A&A...657A.102M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry
Keywords: methods: observational - techniques: photometric -
planets and satellites: fundamental parameters
Abstract:
Meter-sized ground-based telescopes are frequently used today for the
follow-up of extrasolar planet candidates. While the transit signal of
a Jupiter-sized object can typically be detected to a high level of
confidence with small telescope apertures as well, the shallow transit
dips of planets with the size of Neptune and smaller are more
challenging to reveal. We employ new observational data to illustrate
the photometric follow-up capabilities of meter-sized telescopes for
shallow exoplanet transits. We describe in detail the capability of
distinguishing the photometric signal of an exoplanet transit from an
underlying trend in the light curve. The transit depths of the six
targets we observed, Kepler-94b, Kepler-63b, K2-100b, K2-138b,
K2-138c, and K2-138e, range from 3.9ppt down to 0.3ppt. For five
targets of this sample, we provide the first ground-based photometric
follow-up. The timing of three targets is precisely known from
previous observations, and the timing of the other three targets is
uncertain and we aim to constrain it. We detect or rule out the
transit features significantly in single observations for the targets
that show transits of 1.3ppt or deeper. The shallower transit depths
of two targets of 0.6 and 0.8ppt were detected tentatively in single
light curves, and were detected significantly by repeated
observations. Only for the target of the shallowest transit depth of
0.3ppt were we unable to draw a significant conclusion despite
combining five individual light curves. An injection-recovery test on
our real data shows that we detect transits of 1.3ppt depth
significantly in single light curves if the transit is fully covered,
including out-of-transit data toward both sides, in some cases down to
0.7ppt depth. For Kepler-94b, Kepler-63b, and K2-100b, we were able
to verify the ephemeris. In the case of K2-138c with a 0.6ppt deep
transit, we were able to refine it, and in the case of K2-138e, we
ruled out the transit in the time interval of more than ±1.5σ
of its current literature ephemeris.
Description:
We obtained 19 photometric time series of transit events and employed
them to describe the detection capability of ground-based meter-sized
telescopes for shallow exoplanet transits on observational data. At
second, we verified or refined the orbital ephemeris of several
exoplanets.
We present 19 differential photometry time series of transit events of
different extrasolar planets.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 33 4 List of targets
photom.dat 63 3645 ShTr differential transit photometry
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Target of interest
11- 12 I2 h RAh Simbad right ascension (J2000)
14- 15 I2 min RAm Simbad right ascension (J2000)
17- 21 F5.2 s RAs Simbad right ascension (J2000)
23 A1 --- DE- Simbad declination sign (J2000)
24- 25 I2 deg DEd Simbad declination (J2000)
27- 28 I2 arcmin DEm Simbad declination (J2000)
30- 33 F4.1 arcsec DEs Simbad declination (J2000)
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Byte-by-byte Description of file: photom.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Target of interest
12- 33 E22.18 d BJD Barycentric Julian Date (BJD-2400000)
38- 49 E12.6 mag dmag Differential magnitude
52- 63 E12.6 mag e_dmag Uncertainty of differential magnitude
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Acknowledgements:
Matthias Mallonn, mmallonn(at)aip.de
(End) Patricia Vannier [CDS] 28-Oct-2021