It is the first time that two gas giants have been directly imaged around a doppelganger of our sun.

Using ESO’s Very Large Telescope (VLT), researchers have taken the first direct images of a real planetary system around a star such as our sun. A special discovery. Until now, astronomers had never directly observed more than one planet in a twin sister of our Sun. It is therefore the first time that researchers have made direct images of a sun-like star in the company of two giant planets.

Young star
The two newly discovered planets orbit the star TYC 8998-760-1. This star is about 300 light-years away and can be found toward the southern constellation of Musca (Fly). TYC 8998-760-1 is only seventeen million years old, which means that in cosmic terms it is just an ukkepuk. Researcher Alexander Bohn, a PhD student at Leiden University, describes the star as ‘a very young version of our own sun.’ “This discovery is a snapshot of an environment that shares many similarities with our solar system, but at a much earlier stage of development,” he says.

This image, captured by the SPHERE instrument on ESO’s Very Large Telescope, shows the star TYC 8998-760-1 accompanied by two giant exoplanets, TYC 8998-760-1b and TYC 8998-760-1c. This is the first time astronomers have directly observed more than one planet orbiting a star similar to the Sun. The two planets are visible as two bright dots in the centre (TYC 8998-760-1b) and bottom right (TYC 8998-760-1c) of the frame, noted by arrows. Other bright dots, which are background stars, are visible in the image as well. By taking different images at different times, the team were able to distinguish the planets from the background stars.    The image was captured by blocking the light from the young, Sun-like star (top-left of centre) using a coronagraph, which allows for the fainter planets to be detected. The bright and dark rings we see on the star’s image are optical artefacts. 

And so – as you can see in the picture above – two exoplanets orbit this young star. “Our team has now successfully captured two accompanying gas giants revolving around a young doppelganger of our sun,” Maddalena Reggiani emphasizes. The two planets can be seen in the new image as two bright points of light that are located at a considerable distance from their parent star. By taking different pictures at different times, the team was able to distinguish these planets from the background stars.

Method

The discovery of the two giant planets around TYC 8998-760-1 was made possible thanks to the SPHERE instrument equipped with the VLT in the Chilean Atacama Desert. SPHERE shields the light from the star using a so-called coronagraph. This filters out starlight, making weaker planets more visible. Where older planets, such as those in our solar system, are too cool to be detected using this technique, young planets are still so warm that they glow brightly in the infrared. By taking multiple photos over the past year and including older data from 2017, the research team has been able to confirm that the two planets are actually part of the star system.

The two gas giants orbit their mother star at distances of 160 and approximately 320 times the distance between the sun and our Earth. They are thus much further away from their star than Jupiter or Saturn – the two gas giants of our solar system – from the sun. These planets are spaced only five and ten times the distance from Sun to Earth, respectively. The team also discovered that both exoplanets are much heavier than those in our own solar system. The innermost has fourteen times the mass of Jupiter, the outer sixth.

Rare
The discovery of the two planets is, as said, very special. “Although astronomers have already indirectly detected thousands of planets in our Milky Way galaxy, only a small fraction of these exoplanets have been directly imaged,” explains researcher Matthew Kenworthy. Direct images of two or more exoplanets at the same star are even rarer: they have only been successful twice so far, both at stars clearly different from our Sun. The new images from the VLT therefore include the first direct images of a sun-like star that houses more than one planet.

Direct observations
Making direct observations is very important. “This is important in the search for environments where life is possible,” says Kenworthy. In addition, the new observations can help astronomers understand how the planets formed and evolved around our own sun. Follow-up observations are already ahead. The researchers plan to observe the system with the future Extremely Large Telescope (ELT). This will enable astronomers to investigate whether the newly discovered planets originated at their current distance from their or have migrated from elsewhere. The interactions between the two young planets can also be investigated with the ELT. “The possibility that future instruments – such as those on the ELT – will be able to detect less massive planets near this star, brings an important milestone closer in the study of multiple planetary systems, ”Bohn concludes. “And this may have implications for the history of our own solar system.”

The discovery of the two gas giants using the VLT is already the second major discovery in just a few weeks. Recently, the telescope delivered stunning images showing the birth of a planet . And these recordings provided important clues that give scientists more insight into how planets see the light of day.

Hits: 4

By admin

Leave a Reply