It would appear that yet another extrasolar planet has been directly observed!
Only last week, the Hubble Space Telescope released news that it had spotted an exoplanet orbiting the star Fomalhaut. This is the first ever direct observation of an exoplanet in optical wavelengths. On the same day, joint observations by the ground-based (adaptive optics-powered) Keck II and Gemini infrared telescopes discovered a collection of three large alien worlds orbiting a star catalogued as HR 8799.
Today, a completely different observatory appears to have discovered yet another exoplanet orbiting the hot star Beta Pictoris (in the constellation of Pictor). European Southern Observatory (ESO) astronomers have directly imaged β Pictoris b, an alien planet orbiting 8 AU from its host star.
A phenomenal achievement considering β Pictoris is over 63 light years away…
It has been known for a very long time that β Pictoris is surrounded by a dusty disk of debris. In fact, astronomers have even gone as far as uncovering cometary activity around the A6V star by analysing the warped planetary disk. It was thought this warping was caused by a massive planet orbiting the star — it would appear they were right.
“These are indirect, but tell-tale signs that strongly suggest the presence of a massive planet lying between 5 and 10 times the mean Earth-Sun distance from its host star,” said Anne-Marie Lagrange, team leader of this discovery. “However, probing the very inner region of the disc, so close to the glowing star, is a most challenging task.”
For a long time, the French team astronomers at the ESO have been analysing near-infrared wavelengths observed by the Very Large Telescope (VLT) based in the Atacama desert, northern Chile, to characterise β Pictoris and its surrounding disk. The main advantage of the VLT is the system’s utilization of adaptive optics that cancel out turbulent effects in the Earth’s atmosphere. This enables astronomers to observe distant stars with outstanding clarity and detail.
According to the ESO press release, the VLT is very well-suited for exoplanet searches. By using a novel approach by Lagrange’s team, the French researchers were able to deduce that the body orbiting the host star was in fact the massive planet thought to be in the β Pictoris system. “Our observations point to the presence of a giant planet, about 8 times as massive as Jupiter and with a projected distance from its star of about 8 times the Earth-Sun distance, which is about the distance of Saturn in our Solar System,” said Lagrange.
Therefore, β Pictoris b has the tightest stellar orbit of any of the previously discovered exoplanets.
The exoplanet hunters have worked hard to establish whether this new discovery is in fact and exoplanet and so far, it appears to be the case. However, on analysing Hubble data, no planetary body was obvious around β Pictoris, but this is not too surprising as the alien world has such a tight orbit around the star. Although more observations are required, the researchers are very confident they have added another direct observation of an extrasolar planet to the growing list…