Two planets around a red dwarf

Date:
October 16, 2020
Source:
University of Bern
Summary:
Astronomers have detected two exoplanets orbiting the star
TOI-1266. The telescope thus demonstrates its high precision
and takes an important step in the quest of finding potentially
habitable worlds.



FULL STORY ========================================================================== Astronomers have detected two exoplanets orbiting the star TOI-1266. The Mexico-based telescope thus demonstrates its high precision and takes
an important step in the quest of finding potentially habitable worlds.


==========================================================================
Red dwarfs are the coolest kind of star. As such, they potentially allow
liquid water to exist on planets that are quite close to them. In the
search for habitable worlds beyond the borders of our solar system,
this is a big advantage: the distance between an exoplanet and its
star is a crucial factor for its detection. The closer the two are,
the higher the chance that astronomers can detect the planet from Earth.

"But these stars are rather small and emit little light compared
to most other stars, such as our Sun," Brice-Olivier Demory, lead
author of the study and Professor of Astrophysics at the University
of Bern explains. These factors make them challenging to observe in
detail. Without the proper instruments, any planets that might orbit them
could easily be overlooked -- especially terrestrial planets, like Earth,
that are comparably small.

A dedicated telescope One instrument, with which it is possible to
study red dwarfs and their planets closely, is the Mexico-based SAINT-EX telescope, co-operated by the NCCR PlanetS. SAINT-EX is an acronym that
stands for Search And characterIsatioN of Transiting EXoplanets. The
project has been named in honor of Antoine de Saint- Exupe'ry (Saint-Ex),
the famous writer, poet and aviator.

The SAINT-EX Observatory is a fully robotic facility hosting a 1-metre telescope. It is equipped with instrumentation specifically suited to
enable high-precision detection of small planets orbiting cool stars. Now,
this specialization pays off: earlier this year, the telescope was able
to detect two exoplanets orbiting the star TOI-1266, located around
120 light years from Earth. The research, published recently in the
journal Astronomy and Astrophysics, provides a first impression of
their characteristics.



==========================================================================
A peculiar pair Compared to the planets in our solar system, TOI-1266
b and c are much closer to their star -- it takes them only 11 and 19
days respectively to orbit it.

However, as their host star is much cooler than the Sun, their
temperatures are not very extreme: the outer planet has approximately
the temperature of Venus (although it is 7 times closer to its star than
Venus is to the Sun). The two planets are of similar density, possibly corresponding to a composition of about a half of rocky and metallic
material and half water. This makes them about half as rocky as Earth
or Venus but also far rockier than Uranus or Neptune.

In size, the planets clearly differ from each other. The inner planet,
TOI-1266 b, measures up to a little under two-and-a-half times the
Earth's diameter.

This makes it a so-called "sub-Neptune." The outer planet, TOI-1266 c, is
just over one-and-a-half times the size of our planet. Thus, it belongs
to the category of "super-Earths." This places the two planets at the
edges of the so-called radius-valley, as Brice-Olivier Demory explains: "Planets between about the radius of TOI-1266 b and c are quite rare,
likely because of the effect of strong irradiation from the star,
which can erode their atmospheres." Yilen Go'mez Maqueo Chew, SAINT- EX
Project Coordinator and researcher at the National Autonomous University
of Mexico adds: "Being able to study two different types of planets in
the same system is a great opportunity to better understand how these
different sized planets come to be." Good timing and help from the
embassy Having this opportunity, especially this year, is anything but
a given. The scientists were fortunate enough to be able to complete
their observations shortly before the Covid-19-related lockdown in
Mexico. Shortly after the observations were made, the observatory
had to be closed due to the consequences of the pandemic. This has
not changed until today. The scientists hope to resume operations of
SAINT-EX in the next few months and to target the next red dwarf and
its potential planets. "Also, the Mexican Embassy in Bern was a great
help in facilitating the discussions with the Mexican government and in providing continued support to the project," says Demory.



========================================================================== SAINT-EX -- Search and characterisation of exoplanets SAINT-EX is
an international collaboration which had its kick-off meeting in the
National Astronomical Observatory in San Pedro Martir (MEX) in September
of 2016. The project's principal investigator is Prof. Brice-Olivier
Demory, from the Center for Space and Habitability of the University
of Bern in Switzerland and National Center of Competence in Research
PlanetS; the project's coordinator and leader in Mexico is Dr. Yilen
Gomez Maqueo Chew from the Instituto de Astronomi'a of the Universidad
Nacional Autonoma de Mexico (UNAM).

Also, part of the project are Prof. Willy Benz from the National
Center of Competence in Research PlanetS, Prof. Franc,ois Bouchy from
the University of Geneva in Switzerland, Dr. Michae"l Gillon from the University of Lie`ge in Belgium, Prof. Kevin Heng from the University
of Bern in Switzerland, Prof.

Didier Queloz from the University of Geneva, Switzerland, and Cambridge
in the UK, and Dr. Laurence Sabin, also from Instituto de Astronomi'a
de Astronomi'a in UNAM. SAINT-EX has been funded by the Swiss National
Science Foundation and the Universities of Bern, Geneva, Lie`ge and
Cambridge as well as UNAM. SAINT- EX also received support from the
National Council for Science and Technology (CONACYT) through the National Laboratories call for proposals for the National Astronomical Observatory
of San Pedro Martir.

Bernese space exploration: With the world's elite since the first moon
landing When the second man, "Buzz" Aldrin, stepped out of the lunar
module on July 21, 1969, the first task he did was to set up the Bernese
Solar Wind Composition experiment (SWC) also known as the "solar wind
sail" by planting it in the ground of the moon, even before the American
flag. This experiment, which was planned and the results analysed by
Prof. Dr. Johannes Geiss and his team from the Physics Institute of
the University of Bern, was the first great highlight in the history
of Bernese space exploration. Ever since Bernese space exploration has
been among the world's elite. The numbers are impressive: 25 times were instruments flown into the upper atmosphere and ionosphere using rockets (1967-1993), 9 times into the stratosphere with balloon flights (1991-
2008), over 30 instruments were flown on space probes, and with CHEOPS the University of Bern shares responsibility with ESA for a whole mission. The successful work of the Department of Space Research and Planetary Sciences
(WP) from the Physics Institute of the University of Bern was consolidated
by the foundation of a university competence center, the Center for
Space and Habitability (CSH). The Swiss National Fund also awarded the University of Bern the National Center of Competence in Research (NCCR) PlanetS, which it manages together with the University of Geneva.


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


========================================================================== Journal Reference:
1. B.-O. Demory, F. J. Pozuelos, Y. Go'mez Maqueo Chew, L. Sabin, R.

Petrucci, U. Schroffenegger, S. L. Grimm, M. Sestovic, M. Gillon, J.

McCormac, K. Barkaoui, W. Benz, A. Bieryla, F. Bouchy, A. Burdanov,
K. A.

Collins, J. de Wit, C. D. Dressing, L. J. Garcia, S. Giacalone, P.

Guerra, J. Haldemann, K. Heng, E. Jehin, E. Jofre', S. R. Kane,
J. Lillo- Box, V. Maigne', C. Mordasini, B. M. Morris, P. Niraula,
D. Queloz, B. V.

Rackham, A. B. Savel, A. Soubkiou, G. Srdoc, K. G. Stassun,
A. H. M. J.

Triaud, R. Zambelli, G. Ricker, D. W. Latham, S. Seager,
J. N. Winn, J.

M. Jenkins, T. Calvario-Vela'squez, J. A. Franco Herrera,
E. Colorado, E.

O. Cadena Zepeda, L. Figueroa, A. M. Watson, E. E. Lugo-Ibarra, L.

Carigi, G. Guisa, J. Herrera, G. Sierra Di'az, J. C. Sua'rez,
D. Barrado, N. M. Batalha, Z. Benkhaldoun, A. Chontos, F. Dai,
Z. Essack, M.

Ghachoui, C. X. Huang, D. Huber, H. Isaacson, J. J. Lissauer,
M. Morales- Caldero'n, P. Robertson, A. Roy, J. D. Twicken,
A. Vanderburg, L. M.

Weiss. A super-Earth and a sub-Neptune orbiting the bright, quiet
M3 dwarf TOI-1266. Astronomy & Astrophysics, 2020; 642: A49 DOI:
10.1051/ 0004-6361/202038616 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201016112852.htm

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