- Tram Ho
Have you ever wanted to see an alien world? A planet orbiting a distant star, light years from the Sun? The James Webb Space Telescope (JWST) just captured its first image of that – a planet orbiting a distant star, Space.com reports.
JWST’s newly revealed images will be a great tool for astronomers to improve their knowledge of exoplanets.
Observe the hidden, distant world
Over the past three decades, we have lived through a great revolution – the dawn of the Exoplanet Era. Where we know no other planets orbit distant stars, and wonder if the Solar System is the only one. Thanks to the advancement of science and technology, we now know that planets are everywhere.
But most of those exoplanets were discovered indirectly . They orbit their host stars so closely that, with current technology, we cannot see them directly. Instead, we watch their host stars do something unexpected and infer the presence of their ‘unseen’ exoplanets.
Of all those alien worlds, only a few have been seen directly . For example, there is the star system HR 8799 , with its four giant planets that have been photographed so often that astronomers have produced a video showing them orbiting around their host star.
The sequence of four images taken by the James Webb Space Telescope shows the exoplanet world, HIP 65426b, captured by the first infrared telescope. Source: NASA/ESA/CSA, A Carter (UCSC), ERS group 1386 and A. Pagan (STScI))
To collect JWST’s first direct images of an exoplanet, astronomers pointed their telescopes at the star HIP 65426. Then, the star’s giant companion HIP 65426b discovered using live images in 2017.
The exoplanet HIP 65426b is unusual in a number of ways – all of which work to make it a particularly “easy” target for direct imaging. First, it is a long distance from its host star, orbiting HIP 65426 about 92 times the distance between Earth and the Sun. (That is, HIP 65426b is about 14 billion kilometers from its star.) From the scientific point of view, this creates a “reasonable” distance, making it easier to observe.
Next, HIP 65426b is a giant world – thought to be several times the mass of the Sun’s largest planet – Jupiter – hence the name Super Jupiter. In addition, it has also been previously found to be very hot, with temperatures at its cloud tops at least 1,200 degrees Celsius.
How are the images taken and what do they show us?
Under normal circumstances, the light from HIP 65426 would completely overwhelm the light from the planet HIP 65426b, regardless of the distance between them.
To get around this, JWST carries a number of “coronagraphs,” instruments that allow telescopes to block light from a bright star in search of fainter objects next to it. This is like using your hand to block the headlights of a car to see other objects.
Using the coronagraph method, JWST took a series of images of HIP 65426b, each taken at a different wavelength of infrared light. In each image, the planet can be clearly seen – a single bright pixel from the position of its occult stellar host.
JWST’s first images of an exoplanet, HIP 65426b, are shown at the bottom of a wider image showing its host star. The images are taken at different wavelengths of infrared light. Image source: NASA/ESA/CSA, A Carter (UCSC), ERS group 1386 and A. Pagan (STScI).
According to NASA, purple shows the view of the NIRCam instrument at 3.00 microns, blue shows the view of the NIRCam instrument at 4.44 microns, and yellow shows the view of the MIRI instrument at 4.44 microns, NASA said. 11.4 microns and red shows the view of the MIRI device at 15.5 microns. These images look different due to the ways in which different James Webb glass instruments pick up light.
The small white star in each image marks the location of the host star HIP 65426, which has been attenuated using coronagraph and image processing.
The researchers leading the observations found that JWST is performing about 10 times better than expected – an outcome that has astronomers around the globe excited to see what happens next. .
Using their observations, they determined that HIP 65426b’s mass is almost seven times that of Jupiter. In addition, the data show that the planet is hotter than expected (with cloud tops of more than 1,000 degrees Celsius) and has a radius of approximately 1.5 Jupiter’s radius.
These images paint a picture of a completely alien world, unlike anything in the Solar System.
Signs for the future
The observations of HIP 65426b are just the first indication of what JWST can do in imaging exoplanets around other stars.
The incredible accuracy of the imaging data suggests that JWST will be able to directly observe smaller planets than previously expected. Instead of being restricted to planets with more mass than Jupiter, it can see planets comparable to, or even smaller than, Saturn.
This is a really interesting discovery. The fact that JWST can see smaller and dimmer planets is expected to greatly increase the number of possible exoplanet targets for astronomers.
The James Webb Space Telescope (JWST) is worth $10 billion. Photo: NASA
In addition, the precision with which JWST made these measurements suggests that we should be able to learn more about their atmospheres than expected. Repeated telescope observations can even reveal details about how those atmospheres have changed over time.
In the coming years, international astronomers expect to see more images of the exoplanet world taken by JWST. While those images may not sound like science fiction, they will still revolutionize our understanding of planets around other stars.
According to NASA, the James Webb Space Telescope (JWST) – jointly built by three NASA agencies, the European Space Agency (ESA) and the Canadian Space Agency (CSA) – is at a distance from our Earth. about 1.5 million km – at the so-called second Lagrange (L2) point. L2’s perfect environment and physical condition will help JWST show off its infrared observation power.
Theverge said, JWST space telescope is invested with a total cost of 10 billion USD. The nearly $10 billion price tag for JWST is a lifetime cost for NASA, including much of its development since the early 2000s, as well as its first five years of operation, according to the report. Planetary Society .
Articles source: Space.com, Theverge, Webbtelescope
Source : Genk