- For the first time, ESO has captured the formation of planet around a young star, PDS 70.
- A planet-hunting equipment, named SPHERE, observed the star system at different wavelengths and epochs.
- The planet’s spectrum suggests that it has a cloudy atmosphere.
Our understanding of the formation and evolution of planets has developed a lot since the first detection of an extrasolar planet (1995). Today, we are facing a vast diversity of planetary system architecture.
It’s still challenging to find the location of planet formation, constrain formation time scales, and analyze physical properties of such bodies. Most of the data are based on indirect parameters obtained from protoplanetary disks.
Recently, European Southern Observatory (ESO), for the first time captured the formation of planet around a young star in the dusty disc. The newborn planet is carving a path through the primordial disk of dust and gas around PDS 70, a young dwarf star.
Instruments Used To Capture The Image
The image was captured by Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), an adaptive optics system installed on ESO’s Very Large Telescope. It operates in near-infrared and visible wavelengths, and provides direct imaging, polarimetric and spectroscopic characterization of exoplanets (planets outside our solar system).
SPHERE consists of numerous subsystems, including Common Path and Infrastructure (CPI), Infrared Dual-band Imager and Spectrograph (IRDIS), Integral Field Spectrograph and Zurich Imaging Polarimeter.
Researchers at the Max Planck Institute for Astronomy (Germany) analyzed the data and found that the atmosphere of the planet is cloudy. They measured the planet’s brightness at multiple wavelengths, which helped them uncover more insights of its atmosphere.
The Newborn Planet
Birth of a new planet PDS 70B | Credit: ESO/A. Müller et al
The planet is clearly visible as a bright point on the right hand side of the dark center. It’s located about 1.8 billion miles from the central star – same as the distance between the Sun and Uranus.
The black circular region at the center is due to the coronagraph – a telescopic attachment developed to block out the direct light from other nearby bodies like stars. It enables researchers to detect its fainter disc that would otherwise be overwhelmed by the extreme luminance of PDS 70.
Most planets are formed in these discs around dwarf stars. However, we haven’t been able to detect solid evidences of these newborn planets inside such discs. The reason is, until now, majority of these planets could just have been features in the disc.
The data suggest that PDS 70B is a massive gas planet (bigger than Jupiter), and its surface temperature is nearly 1,000 degree Celsius. To put this into context, the hottest planet in our solar system is Venus with an average temperature of more than 467 degree Celsius.
Widefield sky around PDS70 | Credit: ESO
The planetary companion of PDS 70 has carved a protoplanetary disc with a massive ‘hole’ in the center. Scientists have known about these inner gaps for more than a decade, and they postulated that they were generated by the interaction between the planet and disc. Now we can actually observe the planet, thanks to the advanced instruments like SPHERE.
These outcomes provide us with a new window onto the immensely complex and poorly-known early phases of planetary evolution. By establishing the atmospheric and physical properties of the planet, the researchers are able to investigate theoretical models of planet formation.