Here is the first picture of a planet embryo

The study of the exoplanets (the planets outside our solar system) is a very young science, made possible by the dazzling technological progress of recent years on our telescopes. The first were detected in the 90s, and there were about fifty in 2000. Since then, the meter has exploded: we are now approaching 4000.

But if astronomers are very good at guessing the presence of distant planets thanks to the variation of luminosity or the small movements that they inflict on their star, it is still difficult to photograph them. The real photos of exoplanets can be counted on the fingers of the hand, or almost. The planet must be very big, very far from its star to distinguish the two bodies, and the telescope camera can correct the turbulence of our atmosphere (we call this adaptive optics). The images obtained are very rudimentary:

The exoplanet HD 131399Ab, in the center of the photo, revolves around the star HD 131399A, on the top left. Bottom right, a system of double stars. (Photo ESO / K. Wagner et al.)

Today, it is an even more impressive image than the ESO, the European Southern Observatory, unveils. In Chile, the Sphere camera that equips the Very Large Telescope photographed a protoplanet, that is to say, a planet embryo.

The big bright spot to the right of the center of the image is a planet being formed. All around her, the disc of dust and gas surrounding the young star PDS 70. (Photo ESO / A. Müller et al.)

An instrument called a coronagraph masks the intense radiation of the star behind a disc opaque: it's the big black circle that we see in the center of the image. Thus, we better distinguish the other sources of light that surround the sun. As PDS 70 is a very young star, it is still wrapped in a large disk of gas and dust. And it is clear that this dust begins to agglomerate into a spheroid object. It will be called planet when it has finished to agglutinate all the dust on the way to its orbit. In the meantime, it's a protoplanet … and this is the first time we've photographed it so clearly.

The protoplanet "is about $ 3 billion kilometers from the central star, which is equivalent to the distance between Uranus and the Sun tells us ESO. The badysis shows that PDS 70b is a gaseous giant with a mbad greater than several times the mbad of Jupiter. The surface temperature of the planet is close to 1,000 degrees Celsius, which is much higher than any planet in our solar system. " The badysis of the light spectrum of the planet suggests that its atmosphere is cloudy.

Camille Gévaudan