the first pictures open a new era in astronomy

By them mistsa group of galaxiesan exoplanet, and a cluster of galaxies and a deep field is therefore the first images and spectra of the James-Webb Space Telescope, which was presented and set in motion the scientific operations. This new era of astronomy has been unanimously welcomed by the scientific community, which expects significant progress in many areas.

James-Webb is the result of an international partnership between NasaI’ESA and the Canadian Space Agency (CSA). ” These first images and spectra of Webb are a huge celebration of the international cooperation that made this ambitious mission possiblesaid Josef Aschbacher, Director-General of ESA. I would like to thank everyone who was involved in commissioning this magnificent telescope and releasing these incredible first images of Webb – you made this historic day a reality. In addition to launch services, ESA has contributed two of the four scientific instruments (the NIRSpec instrument and the optical assembly of the Miri instrument) and provides the necessary staff for mission operations at a total cost of € 700 million. In return for this investment, Europe has a guaranteed minimum of 15% of the observation time, but for the first observation cycle due to the quality of the observation requests from astronomers Europeans, the share awarded to European scientists is around 30%.

SMACS 0723 deep field to the edge of the universe

The first image revealed is the deep field SMACS 0723, whose careful observation tells a story aboutUniverse of all ages, beginning 13.8 billion years ago. This deep field uses gravitational lens of a cluster of galaxies to reveal some of the most distant galaxies ever discovered. With an exposure time of only 12.5 hours, this image only scratches the surface of Webb’s ability to study deep fields. Some of the objects visible in this image are more than 13 billion years old, confirmed Pierre Ferruit, JWST Program Manager at ESA. They formed only a few hundred million years later big bang. The fast reading of the data in this image does not make it possible to date with certainty objects that were formed only a few hundred million years ago after the Big Bang. Further analysis of the image is necessary to have an accurate dating. Other deep fields with longer exposure times will be produced in the coming months, some of which are identical to those inHubble and all indications are that James-Webb will discover galaxies that are only a hundred million years old.

A planetary nebula in our neighborhood

From birth to death of one planetary nebulaJames-Webb can explore dust and gas of stars aging that may one day become a new star or planet. It is worth remembering that the NIRCam and Miri instruments complement each other very well. The first will provide images with a very good level of detail and a very fine reproduction. It is suitable for observing hot objects such as galaxies. Vise versa he will see the dust less well, colder. As for Miri, her main interest is that the stars in her field of vision tend to disappear. This instrument is therefore very useful for observing very cold objects, including dust, and finding light galaxies that are so old that they no longer emit in the visible.

A spectrum that changes the era of planetary spectroscopy

James-Webb discovers molecules of water on an exoplanet, which apparently does not constitute an indication of extraterrestrial life. The interest in this spectrum is to demonstrate a large part of the remarkable properties of the NIRISS instrument. Remarkable because it is the spectrum ininfrared of an exoplanet the most detailed ever collected, the first spectrum that includes wavelengths greater than 1.6 micron to one solution and accuracy, and the first to cover the entire wavelength range from 0.6 microns (visible red light) to 2.8 microns (near infrared) in a single shot.

James-Webb will now study hundreds of other systems to find out what the others are made of atmospheres planetary. Among the already approved observation campaigns should be mentioned the detailed characterization of large organic molecules in the orion trains, the atmosphere of brown dwarfs and observation of several planetary systems, including Trappist-1b. The small Trappist star-1at 40 light years of us, has the special property that it has a fascinating planetary system: seven Earth-like planets, three of which have orbit included between those of Venus and March.

The formation of stars, a strong theme for James-Webb

Stars originate from and contribute to enormous amounts of gas and dust swirling around galaxies. Dust evolves over time, and Webb can study nearby, dynamically interacting galaxies to see dust in action. Now scientists can get a rare glimpse, in unprecedented detail, of how interacting galaxies trigger star formation in each other and how the gas in these galaxies is affected. To get an accurate idea of ​​James-Web’s performance, download the images from the European Space Agency’s JWST page by clicking here and wander through the image.

The complementarity of instruments, one of the strengths of James-Webb

By observing this area of ​​star formation and others like it, scientists can, thanks to James-Webb, see newly formed stars and study the gas and dust that made them.

The bottom image is a composite image captured by the near-infrared instruments (NIRCam) and the middle-infrared instrument (Miri). By merging data from the two instruments, details are revealed.

Comparing James Webb photos to those from Hubble is not as simple as it sounds

The comparison of the James-Webb images with the Hubble images still has limits due to the fact that the two space observatories do not observe at the same wavelength and do not use the same ones. colors. This explains why certain objects are more present in the images of Webb, especially the galaxies that emit in red, than in images of Hubble.

You should also know that the most distant galaxies are not visible to Hubble because they are either offset in red or located behind in clouds very dense dust. In addition, Webb’s sensitivity is such that in all his pictures we will see galaxies in the background! So you have to be very careful when comparing them.

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