Have you ever wanted to see an alien world? A planet orbiting a distant star, light years from the sun? Good , James Webb Space Telescope (JWST) He just brought back his first-ever image – a planet orbiting a distant star.
The new pictures The JWST detection will be a great tool for astronomers aiming to improve their knowledge of exoplanets (planets around other stars) – even better than we hoped it would be!
But for those who have grown up on a diet of Star Trek, Star Wars, and countless sci-fi works, the images can be disappointing. There are no brilliant swirling clouds, in glorious or muted colors. Instead, we only see a point – a single point of light.
So why do these observations excite astronomers? And what might we learn in the coming months and years?
Observation of hidden worlds
Over the past three decades, we have experienced a great revolution – the dawn of the era of exoplanets. Where we once didn’t know about the existence of planets orbiting distant stars, and wondered if the solar system was unique, we now know that planets are everywhere.
At the time of writing, the number of known exoplanets is standing at 5,084And the number increases with each week.
But the vast majority of those exoplanets are discovered indirectly. They orbit so close to their host stars that with current technology, we simply can’t see them directly. Instead, we notice their host stars doing something unexpected, and We conclude from this existence Of their invisible planet companions.
Of all those space worlds, only a few were directly seen. The poster child for such systems is HR 8799whose four giant planets have been photographed so frequently that astronomers have produced a movie showing them moving in their orbits around their host star.
Enter HIP 65426b
To collect the first direct images of an exoplanet, astronomers turned the telescope toward the star HIP 65426, whose massive planetary companion HIP 65426b was Discovered using live imaging in 2017.
The HIP 65426b is unusual in many ways – all of which make it a particularly “easy” target for live shooting. First, it is very far from its host star, orbiting about 92 times more than HIP 65426 from the distance between the Earth and the Sun. This puts it about 14 billion kilometers from its star. In our view, this makes it a “reasonable” distance from the star in the sky, making it easier to observe.
Next, HIP 65426b is a giant of a world – believed to be several times the mass of the largest planet in the solar system, Jupiter. Moreover, it was also previously found to be remarkably hot, with the temperature at the cloud tops being at least 1200°C.
This combination of planet size and temperature means that it is intrinsically bright (of a planet).
How were the photos taken and what do they show us?
Under normal circumstances, the light from HIP 65426 would completely overshadow that from HIP 65426b, despite the distance between them.
To get around this problem, JWST Carrying a coronagraph kit, instruments that allow the telescope to block the light from the bright star to search for faint objects next to it. This is a bit like blocking the headlights of a car with your hand to see if your friend has climbed in to say hello.
Using these vertebrae, 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 offset from the location of its obscured stellar host.
The images are far from your standard science fiction. But they showed that the planet was easily detected, protruding like a sore thumb against the dark background of space.
The researchers who led the observations (Detailed in arXiv prepress server) found that JWST performs about ten times better than expected – a finding that has astronomers around the world excited to see what happens next.
Using their observations, they determined the mass of HIP 65426b (about seven times the mass of Jupiter). Beyond that, the data reveal that the planet is hotter than previously thought (with cloud tops close to 1400℃), and somewhat smaller than expected (about 92% in diameter than Jupiter).
These images paint a picture of a completely alien world, unlike anything in the solar system.
A hint to the future
The HIP 65426b observations are just the first sign of what JWST can do to image planets around other stars.
The astonishing accuracy of the imaging data indicates that JWST will be able to obtain direct observations of smaller planets than previously expected. Rather than being limited to planets larger than Jupiter, it should be able to see planets similar to or even smaller than Saturn.
This is really exciting. You see, the basic rule of astronomy is that there are much more small things than big things. The fact that JWST should be able to see planets smaller and fainter than expected so far Increase the number of possible targets available to astronomers to study.
Moreover, the accuracy with which JWST made these measurements suggests that we will be able to learn more about its atmosphere than expected. Repeated observations with a telescope can reveal details about how these atmospheres vary over time.
So, in the coming years, expect to see more images of space worlds, taken by JWST. While these images may not look like the ones in science fiction, they will revolutionize our understanding of planets around other stars.