## Master Thesis Defense by Nanna Marie Baars Støvelbæk

Supervisor: Christa Gall

Examiner: Liv Hornekær

Titel: Dust formation in type  IIn supernova 2014ab

Abstract: Core collapse supernovae are known to form solids, known as dust grains, out of the elements they produce, however the exact mechanism, timescales and quantities of this dust formation is still unknown.
Type IIn SNe are suggested as playing an important role in this dust production due to the dense material surrounding the star prior to explosion, the circumstellar material.
In this thesis I present my analysis of the type IIn supernova 2014ab using VLT/X-shooter spectra. Analysis of the spectra shows 3 typical signatures of dust: 1) excess emission at near infrared wavelengths due to thermal emission of the dust grains, 2) a blue shift of the peak of prominent emission lines together with 3) an increasing asymmetry of the emission lines due to extinction from the dust grains.
From analysis of prominent emission lines I quantify the extinction from dust and find that it is both time and wavelength dependent, which points to ongoing dust formation in SN 2014ab. From a 2 component model of the whole spectra I show that the infrared excess emission is present in all epochs, and find values for the dust temperature and dust mass of $T_{dust} \sim 1500$ K and $M_{dust} \sim 2.5 \cdot 10^4 - 1.7 \cdot 10^3 M_{\odot}$. With the dust mass depending on the assumed grain species and size. Results are given for graphite and silicate grains of both 0.1 and 1 $\mu$m.
Finally I discuss the implications of my results; whether the results are due to pre-existing dust or ongoing dust formation, where the dust is located and how these results compare to other similar SNe.