Samantha Brown-Sevilla

Samantha Brown Sevilla  (Mexico)

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High-contrast imaging of exoplanets and protoplanetary disks

The number of detected exoplanets is rapidly rising since the first discovery more than two decades ago. However, there are still many open questions regarding their formation and early evolution. Among the detection techniques available nowadays, high-contrast imaging is the one that can give us more insight into answering these questions. Directly imaged planets need to be young (< 1 Gyr) to still be sufficiently bright and have a higher contrast in comparison with their parent stars, which makes them ideal targets to test planet formation theories. Furthermore, high-contrast imaging can also be used to study the environment where planets form, i.e. protoplanetary disks (PPD). Although a couple of forming planets have been imaged within their parent disk, this is not the case with most PPDs with the current facilities. However, one can also study the structure in PPDs, as it can act as the smoking gun of planetary formation. When a planet forms within a disk, it can induce density waves through gravitational disk–planet interactions, which can lead to the formation of spiral arms, rings and/or gaps in the disk. Nonetheless, structure in PPDs can also be caused by gravitational instability (GI) in the disk, or by a combination of both GI and a planetary perturber. Observing in different wavelengths can help to differentiate between the sources of structure in PPDs.

My research is focused on using high-contrast imaging to both detect and characterise exoplanets, and study their formation environments in  search for planet formation signatures. To do this, I use (NIR scattered light) data from the VLT/SPHERE instrument, and additionally from ALMA (sub-mm) to compare and characterise the structures within the disks.

Supervisors:  Wolfgang Brandner / Markus Feldt  (MPIA)

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