Astronomers using the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument on ESO’s Very Large Telescope (VLT) have captured a series of images showing the passage of Beta Pictoris b around its host star.
A stunning and unique time-lapse of the long-period orbit of Beta Pictoris b. Image credit: ESO / Anne-Marie Lagrange / SPHERE Consortium.
Beta Pictoris b is a gas giant approximately 9 to 13 times the mass of Jupiter.
The planet lies around 63 light-years from Earth and is estimated to be only 20 million years old.
It has a day length of approximately 8 hours and orbits its parent star, Beta Pictoris, every 22 years at a distance of 8 times the Earth-Sun distance.
The star also hosts a circumstellar disk of gas and dust that could, in time, evolve into a torus of icy bodies much like Solar System’s Kuiper Belt.
Beta Pictoris b was discovered in November 2008 by University Joseph Fourier astronomer Dr. Anne-Marie Lagrange and co-authors in images captured by VLT’s NaCo (Nasmyth Adaptive Optics System / Near-Infrared Imager and Spectrograph) instrument.
“We then tracked the exoplanet from 2014 until 2016, using the SPHERE — another instrument on VLT,” the scientists said.
“Beta Pictoris b then passed so close to the halo of the star that no instrument could resolve them from one another.”
“Almost two years later, after seeming to merge into the image of the star, Beta Pictoris b emerged from the halo. This reappearance was captured again by SPHERE.”
SPHERE caught sight of Beta Pictoris b by looking at it directly — not by inferring its existence.
Most known exoplanets have been discovered using indirect methods — observing how they affect a star’s position or brightness.
“ESO’s SPHERE specializes in a method called direct imaging, hunting for exoplanets by taking their photographs,” Dr. Lagrange and colleagues said.
“This extraordinarily challenging endeavor provides us with clear images of distant worlds such as Beta Pictoris b.”
The surface of this planet is still hot, around 1,500 degrees Celsius (2,732 degrees Fahrenheit), and the light it emits enabled SPHERE to discover it and track its orbit, seeing it emerge from its passage in front of its parent star.
Whilst a glance at these images might suggest that the planet transits the star, eclipsing a little of its light, Beta Pictoris b does not in fact quite transit.
