Features of the HD 169142 Protoplanetary Disk

Features of the HD 169142 Protoplanetary Disk

A new observation from the ZIMPOL polarimeter reveals the nature of the protoplanetary disk around the star HD 169142.

HD 169142 is 380 light-years distant from us, and its age is 6 million years. About the size of the solar approximately twice. It is known that at least one massive gas giant rotates around it and there is a protoplanetary disk.

It is this disk that became the object of observation from the near infrared to the millimeter range. Surveys have shown that the disk consists of dense dust bands separated by deep gaps. It turned out that in HD 169142 there is a cavity, whose radius reaches 16 a. e., and the annular gap - 32-55 a. e. A more recent study led to a residual disk with a coverage of 0.16–0.48 a. e., and the third narrow gap was located at a distance of 85 a. e. from the star.

Features of the HD 169142 Protoplanetary Disk

HD 169142 Review by ZIMPOL / SPHERE PDI

Astronomers decided to double-check the data to get more details about the structure and properties of the disk. For the study we used a polarimeter ZIMPOL - a subsystem of a spectro-polarimetric high-contrast instrument for the study of exoplanets (SPHERE) on the Very Large Telescope (Chile) The device allowed to find the disk at a distance of 3.5 a. e. from the star and trace it to 126 a. e. A new review confirmed the structure of the faults and showed signs of contact in the planet-disk system in the form of substructures and displacement in the dust distribution.

The study confirmed that the disk is flat, self-shadowed and in contact with the star. They also managed to find a complex irregular substructure of the inner ring of the disk and its position of displacement relative to the star. The ring shows a drop in surface brightness. There is an assumption that the whole thing is in the presence of three major planets located at distances of 15, 35 and 45 a. e.

The review revealed that the gap separating the bright inner ring from the outer disk does not act as a ring, but has an elliptical shape. Perhaps the whole thing in a round external disk, observed when tilted at 13 degrees.

The new review allowed us to obtain a more detailed characterization of the disk of the star HD 169142 and expand knowledge of the aspects of the planetary and stellar formations.

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