J/AJ/170/336 Kepler-1624b transit times from Kepler, LCOGT, & WIRC (Im+, 2025)
Kepler-1624b has no significant transit timing variations.
Im H., Saidel M., Knutson H.A., Greklek-McKeon M., Vissapragada S.,
Collins K.A., Fukui A., Narita N., Paragas K., Schwarz R.P., Shporer A.,
Srdoc G.
<Astron. J., 170, 336 (2025)>
=2025AJ....170..336I 2025AJ....170..336I
ADC_Keywords: Exoplanets; Photometry, infrared; Optical
Keywords: Transits ; Transit timing variation method ; Exoplanet dynamics ;
Exoplanets ; Exoplanet detection methods
Abstract:
It is relatively rare for gas giant planets to have resonant or
near-resonant companions, but these systems are particularly useful
for constraining planet formation and migration models. In this study,
we examine Kepler-1624b, a sub-Saturn orbiting an M dwarf that was
previously found to exhibit transit timing variations (TTVs) with an
amplitude of approximately 2 minutes, suggesting the presence of a
nearby nontransiting companion. We reanalyze the transits from
archival Kepler data and extend the TTV baseline by 11yr by combining
TESS data with three new ground-based transit observations from
Palomar and Las Cumbres Observatories. We jointly fit these datasets
and find that the TTV amplitude is significantly weaker in our updated
analysis. We calculate the Bayes factor for a one-planet versus
two-planet model and find that the one-planet model is preferred. Our
results highlight the need for careful analysis of systems with
relatively low amplitude TTV signals that are identified in large
automated catalogs.
Description:
The Kepler-1624 system was observed during Kepler Quarters 14 through
17, all in long-cadence mode. We obtained the Pre-search Data
Conditioning Simple Aperture Photometry (PDCSAP) light curves from the
Mikulski Archive for Space Telescopes (MAST). We used the transit
midtimes reported in Holczer+2016 (J/ApJS/225/9) to phase up the
transits to make a stacked Kepler transit light curve.
We observed one full transit of Kepler-1624b in the J-band using the
Wide-field Infrared Camera (WIRC) on the 200inch Hale Telescope at
Palomar Observatory in California, USA, on UT 2020 August 6. Science
images were taken with an exposure time of 45s.
We observed two full transits of Kepler-1624b using the Las Cumbres
Observatory Global Telescope (LCOGT). The first transit was observed
on UT 2024 October 11 with the SINISTRO camera, mounted on the 1m
telescope at McDonald Observatory in Texas, USA. Observations were
conducted in the Sloan Digital Sky Survey (SSDS) i-band with an
exposure time of 300s. The second transit was observed on UT 2024
October 24 with the Multicolor Simultaneous Camera for studying
Atmospheres of Transiting exoplanets (MuSCAT3), mounted on the 2m
Faulkes Telescope North (FTN) at the Haleakala Observatory in Maui,
Hawaii, USA. The transit was simultaneously observed in the g, r, i,
and zs bands with exposure times of 300, 291, 174, and 202s,
respectively.
In addition to the Kepler observations, we analyzed TESS photometry from
Sectors 40 and 41 (06/24/21-08/20/21), 54 and 55 (07/09/22-09/01/22),
74 and 75 (01/03/24-02/26/24), and 81 (07/15/24-08/10/24), all in
short-cadence mode. Due to TESS's lower photometric precision, we
found that individual transit midtimes derived from TESS have larger
uncertainties compared to Kepler.
Objects:
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RA (2000) DE Designation(s)
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19 30 19.16 +37 22 35.0 Kepler-1624b = KOI-4928.01
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 39 87 Observed transits of Kepler-1624b
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See also:
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJ/771/129 : Submillimetric Class II sources of Taurus (Andrews+, 2013)
J/A+A/549/A109 : HARPS XXXI. The M-dwarf sample (Bonfils+, 2013)
J/ApJ/807/45 : Potentially habitable planets orbit. M dwarfs (Dressing+, 2015)
J/ApJS/225/9 : Kepler TTVs. IX. The full long-cadence data set (Holczer+, 2016)
J/ApJ/822/86 : False positive proba. for Q1-Q17 DR24 KOIs (Morton+, 2016)
J/AJ/152/158 : Final Kepler transiting planet search (DR25) (Twicken+, 2016)
J/ApJ/834/17 : Mass & radius of planets, moons, low mass stars (Chen+, 2017)
J/ApJS/229/30 : Revis. stellar propert. of Q1-17 Kepler targets (Mathur+, 2017)
J/other/RAA/19.41 : TTVs & linear ephem. of Kepler exoplanets (Gajdos+, 2019)
J/ApJ/892/31 : Teff and metallicities of M dwarfs in APOGEE DR14 (Birky+, 2020)
J/AJ/164/81 : Radial velocity and photometric flux of TOI-3757 (Kanodia+, 2022)
J/MNRAS/510/3449 : KOI planets and KIC stars from Kepler DR25 (Bashi+, 2022)
J/AJ/165/48 : Transit times for Kepler-289 b, c and d (Greklek-McKeon+, 2023)
J/AJ/165/120 : g and i'-band light curve of TOI-5205 with SDSS (Kanodia+, 2023)
J/AJ/166/11 : Stellar properties & RV variability for M-dwarfs (Pass+, 2023)
J/A+A/670/A139 : CARMENES search for exoplanets around M dwarfs (Ribas+, 2023)
J/A+A/689/A250 : Kepler DR25 transit & detec. prob. (Castro-Gonzale+, 2024)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Inst Instrument/source (Source) (1)
16- 19 I4 --- Epoch [0/1367] Epoch number
21- 31 F11.5 d Tmid [6109/10608] Observed midtime for epoch;
BJD-2450000 (midtime)
33- 39 F7.5 d e_Tmid [3.9e-4/1.5e-3] Uncertainty in Tmid (e_midtime)
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Note (1): Instrument as follows:
Kepler = Kepler space telescope (84 occurrences)
LCOGT/MuSCAT3 = Multicolor Simultaneous Camera for studying Atmospheres of
Transiting exoplanets (MuSCAT3), mounted on the 2m Faulkes
Telescope North (FTN) at the Haleakala Observatory in Hawaii,
USA (1 occurrence)
LCOGT/SINISTRO = SINISTRO camera, mounted on the 1m Las Cumbres Observatory
Global Telescope (LCOGT) at McDonald Observatory in Texas, USA
(1 occurrence)
Palomar/WIRC = Wide-field Infrared Camera (WIRC) on the 200inch Hale
Telescope at Palomar Observatory in California, USA
(1 occurrence)
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Robin Leichtnam [CDS] 02-Sep-2026