Confirmed Image of Newborn Planet
An exciting discovery in the world of astronomy has come about recently.
SPHERE, one of the most powerful planet-hunting instruments on ESO’s Very Large Telescope (VLT), has captured the first confirmed image of a planet, named PDS 70b, in the act of forming in the dusty disc surrounding a young star named PDS 70. The young planet, clearly visible as a bright point to the right of the blackened centre of the image, is carving a path through the primordial disc of gas and dust around the very young star. The SPHERE instrument also measured the brightness of the planet at different wavelengths. Due to this, scientists were able to deduce the properties of the exoplanet’s atmosphere.
PDS 70b orbits its parent star, an about 10 million years old low-mass T Tauri Star, (T Tauri stars are a pre-main-sequence Stars which can be found near molecular clouds and are associated with youth (these stars are less than about ten million years old), which is located 370 light years away from Earth in the constellation Centaurus, at a distance of three billion kilometers, roughly equivalent to the distance between Uranus and the Sun, and, as analysis have shown, PDS 70b is a gas giant with several times the mass of Jupiter. With a temperature of about 1000°C, it is much hotter than any planet in our solar system.
Discs, like the one around PDS 70, which has a radius of approximately 140 au and a large gap (~65 au), are birthplaces of planets, but so far only a handful of observations have detected hints of newly formed planets in them and the problem with these observations is, that most of these planet candidates could just have been features in the disc. The dark region at the centre of the image is due to a coronagraph. A coronagraph is a telescopic attachment designed to block out the direct light from a star before it reaches the telescope’s detector. (On a bright day, you maybe use your hand to block the glare of the sun so that you can see other things, this is the same principle behind this instrument).
How on earth are they able to discern detail at those sort of distances?
By my calculation the spatial resolution from the sun to a planet at those kind of distances (370 light years) must be ~ 0.01 arc seconds (assuming an earth orbit) which is beyond what it is capable of (Diffraction limited via xAO: 0.02 to 0.08″ depending on the wavelength – according to the website).
Is it just a very massive planet a long way from the star? Interesting discussion!