South African Astronomical Observatory (SAAO) helps to reveal seven new Earth-sized planets
A new system of seven Earth-sized planets orbiting a star 40 light
years away has been discovered using data from South African
Astronomical Observatory (SAAO) telescope, as well as other
instruments around the world. Three of these planets are located in
the star’s "habitable zone”. This means that they could have liquid
water on their surface, which increases the chances of them hosting
life. This new planetary system now holds the record for the largest
number of Earth-sized planets found.
SAAO’s 1m telescope was used to take observations of the
planetary system over several nights in June and July 2016. The 1m
telescope is equipped with a special camera, called the Sutherland
High Speed Optical Camera (SHOC), which can take up to 70
images per second.
Dr. Amanda Sickafoose, Head of Instrumentation at SAAO, had this
to say about SAAO's involvement in this exciting work: ”This is a
remarkable discovery. To find multiple, possibly habitable exoplanets
orbiting the same star is exciting. This system is quite different from
our Solar System, which also raises new questions. The SAAO is
proud to have played a small role in this advancement in our
understanding of planetary systems."
Other telescopes used in this research include NASA’s Spitzer
Space Telescope and ground-based telescopes in Chile, Morocco,
Hawaii and the Canary Islands.
The planets were observed as they moved in front of their host star,
called TRAPPIST-1, blocking out its light. By carefully measuring the
amount of light blocked out as each planet passes in front of the
star, astronomers were able to determine the sizes of the planets
and the way in which they orbited TRAPPIST-1.
The researchers, lead by Michaël Gillon of the University of Liège in
Belgium, also report that the three planets in the habitable zone are
likely to be rocky planets, like the Earth and Mars, Venus and
Mercury, making this the system with the highest number of rocky
planets in the habitable zone of their parent star.
All seven planets orbit TRAPPIST-1 at a distance smaller than the
orbit of Mercury, the closet planet to our Sun. The planets are able to
orbit so near to TRAPPIST-1 is because it is a small, red dwarf star
with temperatures much cooler than the Sun. The full details of this
new discovery have been published in the journal Nature