18-Aug-2022: Scientists formulate model to trace elusive exo-moons from JWST data

Scientists have developed a model to trace the so far elusive exomoons – natural satellites that revolve around exoplanets (planets orbiting stars other than the Sun) with the help of the James Webb Space Telescope (JWST), launched in December 2021. This may also help detect habitable exo-moons in the future and understand new worlds beyond our own.

So far, five thousand exoplanets --- planets orbiting stars other than the Sun, have been discovered by using several ground-based and space telescopes such as Kepler, CoRoT, Spitzer, and Hubble space telescopes. However, the natural satellites or exomoon around any of these planets still remain untraced.

The Solar system is constituted of a large number of natural satellites with various sizes and mass, and many of them influence the ambient environment of the Solar planets. Therefore, a large number of exomoons are expected to be present, and they may play a crucial role in the habitability of rocky exoplanets in the habitable zone of their host stars. While most exoplanets are detected through photometric transit method, signals from exo-moons are too weak to detect mainly because of their extremely small size.

Scientists at the Indian Institute of Astrophysics, Bangalore, an autonomous institute of the Department of Science and Technology, have demonstrated that the newly launched James Webb Space Telescope (JWST) is sufficiently powerful to detect the transit signal of exomoons in the photometric light curves of moon hosting exoplanets.

Professor Sujan Sengupta and his graduate student Suman Saha have developed an analytical model that uses the radius and orbital properties of the host planet and its moon as parameters to model the photometric transit light curve of moon-hosting exoplanets by incorporating various possible orientations of the moon-planet-star system.

The co-alignment or non-coalignment of the orbits of the planet and the moon are used as parameters (using two angular parameters), and they can be used to model all the possible orbital alignments for a star-planet-moon system. Using these generic models and the analysis of photometric transit light curves of exoplanets that is being obtained by JWST, a large number of exomoons can be detected in near future. According to the researchers, an exo-moon around a gas giant planet like Jupiter in the habitable zone of the host star where temperature is appropriate for water to exist in liquid state may harbour life. Under favourable alignment of moon-planet-star, such exomoon may also be detected by JWST. The research has been accepted for publication in The Astrophysical Journal, which is published by the American Astronomical Society (AAS).

11-Jan-2018: James Webb Space Telescope successfully completes critical testing

NASA’s James Webb Space Telescope the world’s premier infrared space observatory of the next decade — has successfully completed critical testing in a massive thermal vacuum chamber, enabling it to function properly in the extremely cold and airless environment in space in 2019.

The James Webb Space Telescope (JWST) is the largest space telescope ever built. It is an international collaboration of about 17 countries including NASA, European Space Agency (ESA) and the Canadian Space Agency (CSA). When it is launched in 2019, it will be

the world’s biggest and most powerful telescope.

It features a 21.3-foot-wide primary mirror made up of 18 adjustable gold-coated segments. Webb Telescope is a barrier-breaking mission for engineers and astronomers that will help solve mysteries of our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it.

Webb telescope arrived at NASA's Johnson Space Centre in Houston in May 2017, where it underwent critical cryogenic testing for nine months inside Chamber A, a massive thermal vacuum chamber at the centre. On July 10, the cryogenic testing of the telescope began. During approximately 100 days in the chamber, Webb was put through a series of tests designed to ensure the telescope functioned as expected in an extremely cold, airless environment akin to that of space.

Scheduled for launch in the spring of 2019 aboard a European Ariane 5 rocket, the gamut of tests ensured that Webb will safely reach its orbit at Earth's second Lagrange point (L2) and be able to successfully perform its science mission.

When it is launched into space it will be able to peer back in time 3.5 billion years, teaching us more than ever before about the start of the universe. The telescope will be used to look back to the first galaxies born in the early universe more than 13.5 billion years ago, and observe the sources of stars, exoplanets, and even the moons and planets of our solar system.