J/AJ/170/322 Eclipse timing variation from TESS using two models (Esmer+, 2025)
Eclipse timing variations of circumbinary substellar objects in TESS data.
Esmer E.M., Daylan T.
<Astron. J., 170, 322 (2025)>
=2025AJ....170..322E 2025AJ....170..322E
ADC_Keywords: Binaries, eclipsing; Stars, double and multiple; Exoplanets;
Stars, brown dwarf; Models; Photometry; Optical
Keywords: Eclipsing binary stars ; Exoplanet detection methods ;
Timing variation methods ; Exoplanets ; Brown dwarfs
Abstract:
Circumbinary planets and brown dwarfs form in complex gravitational
environments, offering insights into formation, orbital stability, and
habitability prospects. However, they remain underrepresented, with
only 60 confirmed or candidate systems known. In this work, we
leverage TESS photometry to search for circumbinary companions through
eclipse timing variations (ETVs), analyzing 152 detached eclipsing
binaries. By modeling eclipse timings, we identify 37 systems with
significant periodic signals, 19 of which have false-alarm
probabilities below 0.01. One system, TIC 142979644, emerges as a
promising candidate to host a circumbinary substellar companion, with
estimated masses of 18.8MJ and 11.1MJ from different methods.
Simulations using synthetic ETVs indicate a 5% recovery rate for
circumbinary brown dwarfs and 0.1% for Jupiter-like planets, with
median masses of 56.6MJ+16.5MJ-23.4MJ and periods of
1404-953+1361days. Our simulations show that the smallest
detectable mass is 1.6MJ at a period of 1860days and confirm that
ETV methods are effective in detecting misaligned systems. In the
absence of a detection, we set an upper limit of 40% on the occurrence
rate of circumbinary brown dwarfs at the 2σ confidence level. In
contrast, a confirmed single detection would imply an occurrence rate
of 13.08%. These constraints are consistent with previous abundance
estimates for circumbinary brown dwarfs (≤6.5%). As most circumbinary
substellar companions detected through ETVs are found around
post-common envelope binaries, our recovery rate of 0.83% in their
progenitors implies that even a single detection would strongly favor
a first-generation origin.
Description:
We identified our target sample from the TESS Eclipsing Binary
Catalog (TEBC; Prsa+2022, J/ApJS/258/16), focusing on detached binaries.
We retrieved and processed their light curves from TESS observations
accessed via the Mikulski Archive for Space Telescopes (MAST) portal.
For this study, we used simple aperture photometry (SAP) fluxes, as
the presearch data conditioning SAP (PDCSAP) fluxes can introduce
artificial trends that may distort the intrinsic features of eclipsing
binary light curves. We collected only 2min of exposures for each
target, with the last observation for any target occurring in TESS
Sector 80 (06/18/24-07/15/24).
To determine the eclipse parameters of the target binaries, we modeled
their light curves using the allesfitter (Gunther+2021, 2021ApJS..254...13G 2021ApJS..254...13G)
code with a Markov Chain Monte Carlo (MCMC) approach. We calculated
mideclipse times by fitting a generalized Gaussian function separately
to each primary and secondary eclipse in both SAP and PDCSAP light
curves. To assess the reliability of the generalized Gaussian
approach, we compared the resulting ETVs to those derived from
MCMC-based light-curve modeling with allesfitter.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea2.dat 278 152 Eclipse timing variation (ETV) periodogram results
and derived parameters
tablec1.dat 54 3610 Mid-eclipse times and asymmetric errors
(allesfitter)
tablec2.dat 51 16659 Mid-eclipse times and errors (Generalized Gaussian
fits)
--------------------------------------------------------------------------------
See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/other/Sci/337.1511 : Kepler-47 transits (Orosz+, 2012)
J/other/Nat/481.475 : RVs of Kepler-34b & Kepler-35b (Welsh+, 2012)
J/ApJ/768/127 : Q1-11 Kepler light curve of KIC 4862625 (Schwamb+, 2013)
J/MNRAS/448/946 : Kepler eclipse timing variation analyses (Borkovits+, 2015)
J/A+A/593/A38 : SPOTS II. Planets Orbiting Two Stars (Bonavita+, 2016)
J/MNRAS/455/4136 : Kepler triples (Borkovits+, 2016)
J/AJ/153/258 : 2007.5 to 2010.4 HST astrometry of HD 202206 (Benedict+, 2017)
J/A+A/608/A106 : HD 284149 SPHERE/IFS spectrum (Bonavita+, 2017)
J/A+A/604/L6 : EBLM J0555-57 photometry and RV (von Boetticher+, 2017)
J/MNRAS/479/5491 : Absolute parameters of 509 main-sequence stars (Eker+, 2018)
J/A+A/624/A68 : 47 single-line eclipsing binar. BEBOP veloc. (Martin+, 2019)
J/AJ/157/174 : Transit. planets in Kepler-47 circumbinary syst. (Orosz+, 2019)
J/MNRAS/488/4905 : SuperWASP transit false positive catalog (Schanche+, 2019)
J/AJ/157/184 : NY Virginis primary mid-eclipse times (Song+, 2019)
J/A+A/625/A150 : 10 very-low-mass stars photometry (von Boetticher+, 2019)
J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)
J/MNRAS/503/2979 : CSS eclipsing binar. period variations (Papageorgiou+, 2021)
J/ApJS/259/66 : Eclipsing quadruple star candidates from TESS (Kostov+, 2022)
J/ApJS/258/16 : TESS Eclipsing Binary stars. I. Sectors 1-26 (Prsa+, 2022)
J/ApJS/279/50 : TESS Ten Thousand Catalog: Eclipsing Binaries (Kostov+, 2025)
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 I10 --- TIC [3816260/1883519478] TESS Input Catalog
(IV/39) identifier
12- 22 F11.6 d MJD-1 [1322.13/2084.25] Reference mid-time of
primary eclipse; BJD-2457000 at TBD
(Reference-primary-eclipse)
24- 33 F10.7 d PerBin [1.49/13.75] Orbital period of the
eclipsing binary (Period-binary)
35- 39 F5.2 mag Tmag [5.44/13.84] TESS-band magnitude of the
system
41- 47 F7.3 --- RUWE [0.8/42.57]? Gaia DR3 (I/355)
renormalized unit weight error
49- 55 F7.2 d Per3-af [6/2592.82] ETV period of third
companion from allesfitter-based timings
(Period-3-allesfitter)
57- 63 F7.2 min Amp3-af [0.01/1918.62] ETV semi-amplitude of
third companion from allesfitter
(Amplitude-3-allesfitter)
65- 74 E10.2 --- FAP-af [5.2e-27/1]?=1.9e-112 False-alarm
probability from allesfitter
(FAP-allesfitter) (1)
76- 83 F8.2 d Per3-SAP-1 [12.9/2610.89]? ETV period of third
companion from Generalized Gaussian,
Single Aperture Photometry flux, primary
timing (Period-3-GenGauss-SAP-PRI)
85- 91 F7.2 min Amp3-SAP-1 [0.02/168.94]? ETV semi-amplitude of
third companion from Generalized
Gaussian, Single Aperture Photometry,
primary timing
(Amplitude-3-GenGauss-SAP-PRI)
93- 102 E10.2 --- FAP-SAP-1 [1.7e-42/1]?=2.4e-109 False-alarm
probability of third companion from
Generalized Gaussian, Single Aperture
Photometry, primary timing
(FAP-GenGauss-SAP-PRI) (1)
104- 111 F8.2 d Per3-PDCSAP-1 [6.91/2750.69]? ETV period of third
companion from Generalized Gaussian,
Presearch Data Conditioning SAP flux,
primary timing
(Period-3-GenGauss-PDCSAP-PRI)
113- 118 F6.2 min Amp3-PDCSAP-1 [0.03/46.25]? ETV semi-amplitude of
thirdcompanion from Generalized
Gaussian, Presearch Data Conditioning
SAP, primary timing
(Amplitude-3-GenGauss-PDCSAP-PRI)
120- 129 E10.2 --- FAP-PDCSAP-1 [4.2e-41/1]?=4.9e-108 False-alarm
probability from Generalized Gaussian,
Presearch Data Conditioning SAP, primary
timing (FAP-GenGauss-PDCSAP-PRI) (1)
131- 139 F9.2 d Per3-SAP-2 [8.8/10000]? ETV period of third
companion from Generalized Gaussian,
Single Aperture Photometry flux,
secondary timing
(Period-3-GenGauss-SAP-SEC)
141- 147 F7.2 min Amp3-SAP-2 [0.06/611.89]? ETV semi-amplitude of
third companion from Generalized
Gaussian, Single Aperture Photometry,
secondary timing
(Amplitude-3-GenGauss-SAP-SEC)
149- 158 E10.2 --- FAP-SAP-2 [2e-36/1]?=2.9e-112 False-alarm
probability from Generalized Gaussian,
Single Aperture Photometry, secondary
timing (FAP-GenGauss-SAP-SEC) (1)
160- 167 F8.2 d Per3-PDCSAP-2 [8.75/2302.96]? ETV period of third
companion from Generalized Gaussian,
Presearch Data Conditioning SAP flux,
secondary timing
(Period-3-GenGauss-PDCSAP-SEC)
169- 176 F8.2 min Amp3-PDCSAP-2 [0.07/1571.54]? ETV semi-amplitude of
third companion from Generalized
Gaussian, Presearch Data Conditioning
SAP, secondary timing
(Amplitude-3-GenGauss-PDCSAP-SEC)
178- 187 E10.2 --- FAP-PDCSAP-2 [5.3e-35/1]?=1.7e-103 False-alarm
probability from Generalized Gaussian,
Presearch Data Conditioning SAP,
secondary timing
(FAP-GenGauss-PDCSAP-SEC) (1)
189- 193 I5 K Teff1 [3000/10900]? Adopted effective
temperature of primary star
195- 200 F6.2 deg Inc [78.98/88.88]? Binary orbital
inclination (Inc-binary)
202- 208 F7.4 Msun Mass1 [0.21/2.83]? Primary stellar mass from
Mass-Temperature-Radius relations
210- 216 F7.4 Rsun Rad1 [0.23/2.44]? Primary stellar radius from
Mass-Temperature-Radius relations
(Radius1)
218- 224 F7.4 Msun Mass2 [0.11/1.29]? Secondary stellar mass from
Mass-Temperature-Radius or extrapolated
226- 232 F7.4 Rsun Rad2 [0.097/1.47]? Secondary stellar radius
(Radius2)
234- 241 F8.3 Mjup M3sini-af [0.018/215.73]? Projected mass of third
body from allesfitter solution
(M3sini-allesfitter)
243- 250 F8.3 Mjup M3-af [0.018/216.14]? Third-body mass assuming
coplanarity, allesfitter-derived
(M3-allesfitter)
252- 259 F8.3 Mjup M3sini-GG [0.011/223.24]? Projected mass of third
body from Generalized Gaussian solution
(M3sini-GenGauss)
261- 268 F8.3 Mjup M3-GG [0.011/223.67]? Third-body mass assuming
coplanarity, Generalized
Gaussian-derived (M3-GenGauss)
270- 278 F9.4 --- AmpRatio-af [0.061/238.11]? Ratio of expected
dynamical ETV amplitude to
light-travel-time amplitude, allesfitter
timings (A-dyn-over-A-lite-allesfitter)
--------------------------------------------------------------------------------
Note (1): False-alarm probabilities of less than 1e-100 have been set to NULL
in VizieR. The original values are available in the table on the FTP.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 I10 --- TIC [3816260/1883519478] TESS Input Catalog (IV/39)
identifier
12- 27 F16.8 d BJDmid [2458327/2460932] Mid-eclipse time; BJD at TDB
(mid-bjd)
29- 38 E10.9 d e_BJDmid [3.63e-5/0.011] Lower 1σ uncertainty on
BJDmid (e_mid-bjd)
40- 49 E10.9 d E_BJDmid [3.76e-5/0.012] Upper 1σ uncertainty on
BJDmid (E_mid-bjd)
51- 54 I4 --- Cycle [1/1240] Eclipse cycle number
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 I10 --- TIC [3816260/1883519478] TESS Input Catalog (IV/39)
identifier
12- 15 A4 --- Type Light-curve source (data-type) (1)
17- 32 F16.8 d BJDmid [2458325/2460531] Mid-eclipse time; BJD at TBD
(mid-bjd)
34- 43 F10.8 d e_BJDmid [2.69e-5/0.14] The 1σ uncertainty on
BJDmid (e_mid-bjd)
46- 51 F6.1 --- Cycle [-122/1239.5] Eclipse cycle number
--------------------------------------------------------------------------------
Note (1): Data type as follows:
sap = Simple Aperture Photometry flux (7303 occurrences)
pdc = Presearch Data Conditioning flux (7291 occurrences)
ffi = flux extracted from Full Frame Images (2065 occurrences)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
Acknowledgements:
License: CC-BY-4.0
(End) Prepared by [AAS], Robin Leichtnam [CDS] 31-Aug-2026