Unprecedented ground-based discovery ofstrongly interacting
exoplanets

Date:
July 2, 2020
Source:
CNRS
Summary:
Several interacting exoplanets have already been spotted by
satellites.

But a new breakthrough has been achieved with, for the first time,
the detection directly from the ground of an extrasolar system of
this type.

Astronomers have discovered an unusual planetary system, dubbed
WASP-148.



FULL STORY ========================================================================== Several interacting exoplanets have already been spotted by
satellites. But a new breakthrough has been achieved with, for the first
time, the detection directly from the ground of an extrasolar system of
this type.


==========================================================================
An international collaboration including CNRS researchers* has discovered
an unusual planetary system, dubbed WASP-148, using the French instrument SOPHIE at the Observatoire de Haute-Provence (CNRS/Aix-Marseille
Universite';).

The scientists analysed the star's motion and concluded that it hosted
two planets, WASP-148b and WASP-148c. The observations showed that the
two planets were strongly interacting, which was confirmed from other
data**. Whereas the first planet, WASP-148b, orbits its star in nearly
nine days, the second one, WASP-148c, takes four times longer. This ratio between the orbital periods implies that the WASP-148 system is close
to resonance, meaning that there is enhanced gravitational interaction
between the two planets. And it turns out that the astronomers did indeed detect variations in the orbital periods of the planets.

While a single planet, uninfluenced by a second one, would move with
a constant period, WASP-148b and WASP-148c undergo acceleration and deceleration that provides evidence of their interaction.

Their study will shortly be published in the journal Astronomy &
Astrophysics.

Notes * French scientists work in the following laboratories : Institut d'astrophysique de Paris (CNRS/Sorbonne Universite';) ; Observatoire
de Haute- Provence (CNRS/Aix-Marseille Universite';) ; Institut de
me'canique ce'leste et de calcul des e'phe'me'rides (CNRS/Observatoire
de Paris-PSL/Sorbonne Universite';) ; Institut de plane'tologie et d'astrophysique de Grenoble (CNRS/ Universite'; Grenoble Alpes) ;
Laboratoire d'astrophysique de Marseille (CNRS/ Aix-Marseille Universite')
; Laboratoire d'e'tudes spatiales et d'instrumentation en astrophysique (CNRS/Observatoire de Paris-PSL/Sorbonne Universite'/Universite'; de
Paris). They also colaborated with amateur astronomers from Hubert-Reeves Observatory.

** Mesures made with Hubert-Reeves telescope, France, and using SuperWASP, RISE, Carlos Sanchez and Liverpool, Canary Islands, Spain.


========================================================================== Story Source: Materials provided by CNRS. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. G. Hebrard, R.F. Diaz, A.C.M. Correia, A. Collier Cameron,
J. Laskar, D.

Pollacco, al. Discovery and characterization of the exoplanets
WASP-148b and c. A transiting system with two interacting
giant planets. Astronomy & Astrophysics, 2020; DOI:
10.1051/0004-6361/202038296 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200702113250.htm

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