J/ApJ/988/L63 Mid-transit times for TOI-201 b and c (Maciejewski+, 2025)
A Transiting Giant on a 7.7 yr Orbit Revealed by Transit Timing Variations
in the TOI-201 System.
Maciejewski G., Loboda W.
<Astrophys. J. 988, L63 (2025)>
=2025ApJ...988L..63M 2025ApJ...988L..63M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Optical
Keywords: Exoplanets - Exoplanet dynamics - Transit photometry -
Transit timing variation method - Radial velocity
Abstract:
We report the detection and characterization of TOI-201 c, a
long-period transiting companion to the warm Jupiter TOI-201 b. Its
presence was first inferred from high-amplitude transit timing
variations (TTVs) in TOI-201 b, pointing to a massive outer body on a
7.7-0.6+1.0yr eccentric orbit. This prediction was confirmed when
Transiting Exoplanet Survey Satellite observed a transit of TOI-201 c,
precisely constraining its orbital geometry. A joint fit to TTVs,
transit photometry, and archival radial velocities yields a mass of
14.2-1.2+1.0MJup and an eccentricity of 0.643-0.021+0.009.
The mutual inclination between planets b and c is
2.9-4.4+4.8°, indicating a nearly coplanar architecture.
Long-term numerical integrations confirm dynamical stability over
gigayear timescales and predict that transits of TOI-201 b will cease
within a few thousand years. TOI-201 c ranks among the longest-period
transiting planets with well-constrained properties. Its detection via
TTVs, followed by a confirmed transit, represents a rare observational
sequence and highlights the power of TTVs and photometric monitoring
to uncover distant companions. The TOI-201 system offers a valuable
laboratory for testing models of giant planet formation, migration,
and secular evolution in multiplanet systems.
Description:
We provide the mid-transit times for planets b and c in the extrasolar
planetary system TOI-201. They were homogeneously determined from TESS
photometric time series in sectors 2-88. Details on observations and data
processing are provided in the paper.
Objects:
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RA (2000) DE Designation(s)
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05 49 36.41 -54 54 38.6 TOI-201 = HD 39474
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ttimes.dat 50 16 Transit times for TOI-201 b and TOI-201 c
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See also:
J/AJ/161/235 : Radial velocity of TOI-201 (Hobson+, 2021)
Byte-by-byte Description of file: ttimes.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Sector TESS sector
4- 19 F16.8 d Tmid Mid-transit time in Barycentric Julian date
in Barycentric Dynamical Time (BJD_TDB)
21- 30 F10.8 d E_Tmid Positive mid-transit time error
32- 41 F10.8 d e_Tmid Negative mid-transit time error
43- 50 A8 --- Planet Planet name
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Acknowledgements:
Gracjan Maciejewski, gmac(at)umk.pl
Institute of Astronomy, Nicolaus Copernicus University, Poland
(End) Gracjan Maciejewski [Copernicus Univ.], Patricia Vannier [CDS] 29-Jan-2026