Observations explore icy protoplanetary disk of the star PDS 453

Using ESO’s Very Large Telescope (VLT), an international team of astronomers has inspected an icy protoplanetary disk of a young star known as PDS 453. Results of the new study, published on the preprint server arXiv, yield essential information about the structure and composition of this disk.

Protoplanetary disks represent an important stage in the formation of planets. Astronomers believe that the final composition of planets depends on the chemical process taking place within the disk. Therefore, studies of the initial phase of disk formation could be crucial in improving knowledge of the formation and evolution of planetesimals, planets and other objects.

PDS 453 is a young intermediate-mass F-type star located some 424 light years away in the Scorpius-Centaurus OB association. The star is estimated to be about 5 million years old and is assumed to be an intermediate object between a low-mass T Tauri star and a Herbig Ae star.

The protoplanetary disk of PDS 453 was first identified in 2006. It is an edge-on disk with a sharp outer edge potentially due to truncation by a nearby candidate companion object. Previous observations of this disk have found that it contains water ice in its layers above the mid-plane.

Recently, a group of astronomers led by Laurine Martinien of the Grenoble Alpes University in France, has employed VLT’s Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument, to explore the disk of PDS 453 in more detail. The study was complemented by data from the Hubble Space Telescope’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

“In this paper we present archival HST/NICMOS and new VLT/SPHERE data, providing the sharpest and highest contrast image of the disk to date,” the researchers wrote.

The observations found that the protoplanetary disk of PDS 453 has the typical morphology of a highly inclined system with two reflection nebulae. The images show that the disk extends from near the stellar surface to a distance of about 160 AU, with a sharp transition at 70 AU that produces a clear ring-like feature. The disk’s inclination was measured to be 80 degrees.

PDS 453’s disk is composed of a mixture of dust and water ice. It was found that 10% of the inner part and 20% of the outer part of the disk contain (by volume) water ice. This level is similar to what is typically suggested from water ice observations for disks across a wide range of inclinations.

The astronomers concluded that their results suggest that the disk of PDS 453 is in a rare configuration in which our line of sight to the star grazes through the disk’s upper surface. They noted that further observations of this disk, especially using the James Webb Space Telescope (JWST) or the Atacama Large Millimeter/submillimeter Array (ALMA), are needed in order to better constrain the parameters of this structure.

© 2024 Science X Network