Astronomers peer into planet-hosting star for the first time

Astronomers have successfully peered through the "amniotic sac" of a star that is still forming to observe the innermost region of a burgeoning solar system for the first time.

No one so far has been able to probe this close to a star that is still forming and which also has at least one planet so close in.

"We have been able to detect for the first time emission from the innermost part of the disk of gas that surrounds the central star. Unexpectedly, this emission is similar to that of 'barren' young stars that do not show any signs of active planet formation," explained lead researcher Dr Ignacio Mendigutia from University of Leeds.

To observe this distant star called "HD 100546", the astronomers used the Very Large Telescope Interferometer (VLTI) which is based in an observatory in Chile.

HD 100546 is a young star, surrounded by a disk-shaped structure of gas and dust called a "proto-planetary disk", in which planets can form.

"If the star were placed at the centre of our solar system, the outer part of the disk would extend up to around 10 times the orbit of Pluto," Mendigutia noted.

Systems such as HD 100546 which are known to have both a planet and a gap in the "proto-planetary disk" are extremely rare.

"More interestingly, the disk exhibits a gap that is devoid of material. This gap is very large, about 10 times the size of the space that separates the Sun from the Earth," Dr Mendigutia pointed out.

The inner disk of gas could only survive for a few years before being trapped by the central star, so it must be continuously replenished somehow.

"We suggest that the gravitational influence of the still-forming planet - or possibly planets - in the gap could be boosting a transfer of material from the gas-rich outer part of the disk to the inner regions," the authors noted.

"With our observations of the inner disk of gas in the HD 100546 system, we are beginning to understand the earliest life of planet-hosting stars on a scale that is comparable to our Solar System," they concluded..

The research paper was published in the journal Monthly Notices of the Royal Astronomical Society.