J/A+A/694/A233 WASP-43b tidal evolution (Bernabo+, 2025)
Characterizing WASP-43b's interior structure:
Unveiling tidal decay and apsidal motion.
Bernabo L.M., Csizmadia Sz., Smith A.M.S., Harre J.-V., Kalman Sz.,
Cabrera J., Rauer H., Gandolfi D., Pino L., Ehrenreich D., Hatzes A.
<Astron. Astrophys. 694, A233 (2025)>
=2025A&A...694A.233B 2025A&A...694A.233B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities
Keywords: planets and satellites: dynamical evolution and stability -
planets and satellites: gaseous planets -
planets and satellites: interiors - planet-star interactions
Abstract:
Recent developments in exoplanetary research highlight the importance
of Love numbers in understanding their internal dynamics, formation,
migration history and their potential habitability. Love numbers
represent crucial parameters that gauge how exoplanets respond to
external forces such as tidal interactions and rotational effects. By
measuring these responses, we can gain insights into the internal
structure, composition, and density distribution of exoplanets. The
rate of apsidal precession of a planetary orbit is directly linked to
the second-order fluid Love number, thus we can gain valuable insights
into the mass distribution of the planet.
In this context, we aim to re-determine the orbital parameters of
WASP-43b - in particular, orbital period, eccentricity, and argument
of the periastron - and its orbital evolution. We study the outcomes
of the tidal interaction with the host star: whether tidal decay and
periastron precession are occurring in the system.
We observed the system with HARPS, whose data we present for the first
time, and we also analyse the newly acquired JWST full-phase light
curve. We fit jointly archival and new radial velocity and transit and
occultation mid-times, including tidal decay, periastron precession
and long-term acceleration in the system.
We detected a tidal decay rate of dPa/dt=(-1.99±0.50)ms/yr and a
periastron precession rate of
dω/dt=(0.1727+0.0083-0.0089)deg/d=
(621.72+29.88-32.04)arcsec/d. This is the first time that both
periastron precession and tidal decay are simultaneously detected in
an exoplanetary system. The observed tidal interactions can neither be
explained by the tidal contribution to apsidal motion of a non-aligned
stellar or planetary rotation axis nor by assuming non-synchronous
rotation for the planet, and a value for the planetary Love number
cannot be derived. Moreover, we exclude the presence of a second body
- e.g. a distant companion star or a yet undiscovered planet -, down
to a planetary mass of 0.3MJ and up to an orbital period of
3700 days. We leave the question of the cause of the observed apsidal
motion open.
Description:
The mid-transit times used in this paper are listed in Table A.1, and
the mid-occultation times are in Table A.2. These data are taken from
previously published literature and from the Exoplanet Transit
Database (ETD, http://var2.astro.cz/ETD/; Poddany et al.,
2010NewA...15..297P 2010NewA...15..297P) and the ExoClock, https://www.exoclock.space
(Kokori et al., 2022, Exp. Astron., 53, 547) database.
In this work, we used literature and yet unpublished RV data as well
as newly acquired HARPS data. In Table 3, we list details on the
datasets, as labelled in the table, while in Table B.1 we report the
seven RV datasets, where all times are corrected to BJDTDB.
Objects:
-----------------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------------
10 19 38.00 -09 48 22.6 WASP-43 = TIC 36734222
-----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 187 282 Transit mid-timings
tablea2.dat 115 18 Occultation mid-timings
refs.dat 74 22 References
tableb1.dat 32 354 RV datasets
--------------------------------------------------------------------------------
See also:
J/A+A/542/A4 : WASP-43b thirty eclipses (Gillon+, 2012)
J/A+A/563/A41 : WASP-43 OSIRIS transmission spectroscopy (Murgas+, 2014)
J/AJ/161/269 : HST WFC3/UVIS normalized light curve of WASP-43 (Fraine+, 2021)
J/AJ/162/210 : Transit Time Variations (TTVs) of WASP-43 (Davoudi+, 2021)
J/A+A/668/A17 : CHEOPS photometry of WASP-43 (Scandariato+, 2022)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- N Cycle number
6- 18 F13.7 d Tmid Mid-transit time TDB (BJD-2450000)
20- 39 A20 d e_Tmid Mid-transit time error
41-133 A93 --- Obs Observation details
135-187 A53 --- Ref Reference, in refs.dat file
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- N Cycle number
6- 16 F11.6 d Tmid Mid-occultation time TDB (BJD-2450000)
18- 31 A14 d e_Tmid Mid-occultation time error
33- 72 A40 --- Obs Observation details
74-115 A42 --- Ref Reference, in refs.dat file
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Ref Reference code
18- 36 A19 --- BibCode BibCode
38- 55 A18 --- Aut Author's name
57- 74 A18 --- Com Comments
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- ID [1/8] Dataset ID (1)
3- 13 F11.6 d Time Time TDB (BJD-2450000)
15- 23 F9.6 km/s RV Radial velocity
25- 32 F8.6 km/s e_RV Radial velocity error
--------------------------------------------------------------------------------
Note (1): Datasets as follows (table 3):
----------------------------------------------------------------------
ID Nobs Instrument References
(out of transit)
----------------------------------------------------------------------
1 15 (14) CORALIE Hellier et al. (2011A&A...535L...7H 2011A&A...535L...7H)
2 8 ( 7) CORALIE Gillon et al. (2012A&A...542A...4G 2012A&A...542A...4G,
Cat. J/A+A/542/A4)
3 67 (21) HARPS-S This work (PI: Triaud)
4 40 (19) HARPS-S Esposito et al. (2017A&A...601A..53E 2017A&A...601A..53E)
5 21 (10) HARPS-N This work
6 56 (36) HARPS-S This work (PI: Ehrenreich)
7 128 (48) ESPRESSO This work (PI: Pino)
8 19 (18) HARPS-S This work (PI: Csizmadia)
----------------------------------------------------------------------
--------------------------------------------------------------------------------
Acknowledgements:
Lia Marta Bernabo, liamarta.bernabo(at)gmail.com, lia.bernabo(at)dlr.de
(End) Patricia Vannier [CDS] 07-Jan-2025