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| Artist's impression of two Earth-mass planets orbiting the star GJ 1002. Credit: Alejandro Suárez Mascareño and Inés Bonet (IAC) |
An international scientific team led by researchers at the Instituto de
Astrofísica de Canarias (IAC) has discovered the presence of two planets
with Earth-like masses in orbit around the star GJ 1002, a red dwarf not far
from the solar system. Both planets are in the habitability zone of the star
"Nature seems bent on showing us that Earth-like planets are very common.
With these two we now know 7 in planetary systems quite near to the sun,"
explains Alejandro Suárez Mascareño, an IAC researcher, who is the first
author of the study accepted for publication in Astronomy &
Astrophysics.
The newly discovered planets orbit the star GJ 1002, which is at a distance
of less than 16 light years from the solar system. Both of them have masses
similar to that of the Earth, and they are in the habitability zone of their
star. GJ 1002b, the inner of the two, takes little more than 10 days to
complete an orbit around the star, while GJ 1002c needs a little over 21
days.
"GJ 1002 is a red dwarf star, with barely one eighth the mass of the sun. It
is quite a cool, faint star. This means that its habitability zone is very
close to the star," explains Vera María Passegger, a co-author of the
article and an IAC researcher.
The proximity of the star to our solar system implies that the two planets,
especially GJ 1002c, are excellent candidates for the characterization of
their atmospheres based either on their reflected light, or on their thermal
emission.
"The future ANDES spectrograph for the ELT telescope at ESO in which the IAC
is participating, could study the presence of oxygen in the atmosphere of GJ
1002c," notes Jonay I. González Hernández, an IAC researcher who is a
co-author of the article. In addition, both planets satisfy the
characteristics needed for them to be objectives for the future LIFE
mission, which is presently in a study phase.
The discovery was made during a collaboration between the consortia of the
two instruments ESPRESSO and CARMENES. GJ 1002 was observed by CARMENES
between 2017 and 2019, and by ESPRESSO between 2019 and 2021.
"Because of its low temperature the visible light from GJ 1002 is too faint
to measure its variations in velocity with the majority of spectrographs,"
says says Ignasi Ribas, researcher at the Institute of Space Sciences
(ICE-CSIC) and director of the Institut d'Estudis Espacials de Catalunya
(IEEC).
CARMENES has a sensitivity over a wide range of near infrared wavelengths
which is superior to those of other spectrographs aimed at detecting
variations in the velocities of stars, and this allowed it to study GJ 1002,
from the 3.5m telescope at Calar Alto observatory.
The combination of ESPRESSO, and the light gathering power of the VLT 8m
telescopes at ESO allowed measurements to be made with an accuracy of only
30 cm/sec, not attainable with any other instrument in the world.
"Either of the two groups would have had many difficulties if they had
tackled this work independently. Jointly we have been able to get much
further than we would have done acting independently," states Suárez
Mascareño.
Reference:
A. Suárez Mascareño et al, Two temperate Earth-mass planets orbiting the
nearby star GJ 1002, Astronomy & Astrophysics (2022).
DOI: 10.1051/0004-6361/202244991
Tags:
Space & Astrophysics