Astronomers discover a key planetary system to understand the formation mechanism of the mysterious 'super-Earths'
The system, named TOI-2096, consists of two planets orbiting a cool star
in a synchronized dance at approximately 150 light-years from Earth.

Date:
May 25, 2023
Source:
University of Liege
Summary:
A study presents the detection of a system of two planets
slightly larger than Earth orbiting a cold star in a synchronized
dance. Named TOI-2096, the system is located 150 light-years from
Earth. This system, located 150 light-years from Earth, is one of
the best candidates for a detailed study of their atmosphere with
the JWST space telescope.


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FULL STORY ==========================================================================
A study led by researchers of the University of Lie`ge and the CSIC --
using observations from NASA's TESS telescope -- presents the detection
of a system of two planets slightly larger than Earth orbiting a cold
star in a synchronized dance. Named TOI-2096, the system is located 150 light-years from Earth.

The discovery is the result of a close collaboration between European and American universities and was made possible by the US space mission TESS (Transiting Exoplanet Survey Satellite), which aims to find planets
orbiting nearby bright stars. "TESS is conducting an all-sky survey
using the transit method, that is, monitoring the stellar brightness of thousands of stars in the search for a slight dimming, which could be
caused by a planet passing between the star and the observer. However,
despite its power to detect new worlds, the TESS mission needs support
from ground-based telescopes to confirm the planetary nature of the
detected signals," explains Francisco J. Pozuelos, astrophysicist,
first author of the paper, former member of the ExoTIC laboratory at
the Univeristy of Lie`ge, and who has now joined the Spanish National
Research Council (IAA-CSIC).

The planets TOI-2096 b and TOI-2096 c were observed with an international network of ground-based telescopes, allowing their confirmation and characterization. The majority of the transits were obtained with
telescopes of the TRAPPIST and SPECULOOS projects led by the University
of Lie`ge. "Making an exhaustive analysis of the data, we found that the
two planets were in resonant orbits: for each orbit of the outer planet,
the inner planet orbits the star twice," says Mathilde Timmermans,
a doctoral student at the ExoTIC lab at ULie`ge and second author of
the scientific paper. Their periods are therefore very close to being a multiple of each other with about 3.12 days for planet b and about 6.38
days for planet c. This is a very particular configuration, and it causes
a strong gravitational interaction between the planets. This interaction
delays or accelerates the passage of the planets in front of their star
and could lead to the measurement of the planetary masses using larger telescopes in the near future." The researchers behind the discovery
estimate that the radius of planet b - - the closest to its star -- is 1.2 times that of Earth, hence the name 'super- Earth'. Its properties could
be similar to Earth's: a planet with a mostly rocky composition, possibly surrounded by a thin atmosphere. Similarly, the radius of planet c is
1.9 times the radius of the Earth and 55% that of Neptune, which could
place the planet in the category of 'mini-Neptunes', planets composed
of a rocky and icy core surrounded by extended hydrogen- or water-rich atmospheres, such as Uranus and Neptune in our Solar System. These
sizes are very interesting because the number of planets with a radius
between 1.5 and 2.5 Earth radii is smaller than what theoretical models predict, making these planets a rarity. These planets are of crucial
importance given their sizes," notes Mathilde Timmermans, "the formation
of super-Earths and mini- Neptunes remains a mystery today. There
are several formation models trying to explain it, but none fits the observations perfectly. TOI-2096 is the only system found to date that has
a super-Earth and a mini-Neptune precisely at the sizes where the models contradict each other. In other words, TOI-2096 may be the system we've
been looking for to understand how these planetary systems have formed." "Furthermore, these planets are among the best in their category to study
their possible atmospheres," explains Francisco J. Pozuelos. Thanks to
the relative sizes of the planets with respect to the host star, as well
as the brightness of the star, we find that this system is one of the
best candidates for a detailed study of their atmosphere with the JWST
space telescope. We hope to be able to do this quickly by coordinating
with other universities and research centers. These studies will help
confirm the presence of an atmosphere, extensive or not, around planets
b and c and thus give us clues as to their formation mechanism."
* RELATED_TOPICS
o Space_&_Time
# Extrasolar_Planets # Kuiper_Belt # Solar_System #
Stars # Pluto # Astronomy # Satellites # Space_Telescopes
* RELATED_TERMS
o Space_observatory o Spitzer_space_telescope o Light-year o
Venus o Titan_(moon) o History_of_Earth o Planet o Milky_Way

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


========================================================================== Journal Reference:
1. F. J. Pozuelos, M. Timmermans, B. V. Rackham, L. J. Garcia, A. J.

Burgasser, S. R. Kane, M. N. Gu"nther, K. G. Stassun, V. Van
Grootel, M.

De'vora-Pajares, R. Luque, B. Edwards, P. Niraula, N. Schanche,
R. D.

Wells, E. Ducrot, S. Howell, D. Sebastian, K. Barkaoui, W. Waalkes,
C.

Cadieux, R. Doyon, R. P. Boyle, J. Dietrich, A. Burdanov,
L. Delrez, B.- O. Demory, J. de Wit, G. Dransfield, M. Gillon,
Y. Go'mez Maqueo Chew, M.

J. Hooton, E. Jehin, C. A. Murray, P. P. Pedersen, D. Queloz, S. J.

Thompson, A. H. M. J. Triaud, S. Zu'n~iga-Ferna'ndez, K. A. Collins,
M. M Fausnaugh, C. Hedges, K. M. Hesse, J. M. Jenkins, M. Kunimoto,
D. W.

Latham, A. Shporer, E. B. Ting, G. Torres, P. Amado, J. R. Rodo'n,
C.

Rodri'guez-Lo'pez, J. C. Sua'rez, R. Alonso, Z. Benkhaldoun,
Z. K. Berta- Thompson, P. Chinchilla, M. Ghachoui,
M. A. Go'mez-Mun~oz, R. Rebolo, L.

Sabin, U. Schroffenegger, E. Furlan, C. Gnilka, K. Lester,
N. Scott, C.

Aganze, R. Gerasimov, C. Hsu, C. Theissen, D. Apai, W. P. Chen,
P. Gabor, T. Henning, L. Mancini. A super-Earth and a mini-Neptune
near the 2:1 MMR straddling the radius valley around the nearby
mid-M dwarf TOI-2096.

Astronomy & Astrophysics, 2023; 672: A70 DOI:
10.1051/0004-6361/202245440 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/05/230525141455.htm

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