Stjärnbildning i infraröda mörka moln. Jakten efter bildning av massiva stjärnor i dess tidiga stadie

Examensarbete för kandidatexamen
Almqvist, Martin
Gascon Rubin, Greta
Nguyen, Anna
Nilsson, Johan
Rumar Karlquist, Johan
Massive stars play an important role in the formation and development of the Uni verse, affecting the evolution of galaxies and planets to a high extent. Despite their importance, much about the mechanisms of massive star formation is still unknown. Massive stars go through their evolutionary stages at a higher pace than their low mass counterparts and spend their initial stages deeply embedded in cocoons of gas and dust. Moreover, they usually form at great distances from the Earth, which makes them challenging to observe with an angular resolution sufficient to resolve their inner structures spatially. In light of all these factors, it is difficult to gain good insight into the mechanisms occurring during the early stages of massive star formation, making the validation of current theories extremely challenging. In this thesis, we aim to study the IRDC G31.98+0.07 and analyse its star formation activi ty to contribute to a better understanding of the properties of massive stars and the processes of their evolutionary stages. Data from multiple telescopes and different wavelengths were used to analyse the cloud through data mapping, cross-matching and use of mass and age models (through SED fitting and PARSEC modelling). Using IR images from Spitzer, SOFIA and Herschel telescopes, we identify 13 point like sources located across the cloud area. For 3 of these 13 cores, data at millimetre wavelengths obtained with the IRAM telescope and ALMA was used to further ana lyse the level of star formation activity. Toward these three cores, our spectral energy distribution analysis predicts masses for forming stars in the range of 8 to 32M⊙ consistent with the high-mass regime. Furthermore, the high-resolution ALMA data does not show evidence of fragmentation towards one of the cores. This may be consistent with a Core Accretion scenario. For the 13 cores, we attempt a deeper investigation using Gaia data and find a good match within the Gaia catalogue for 13 sources. For these sources, we estimate mass and age and discuss in detail the validity of our findings. In summary, the IRDC G31.98+0.07 shows some indication of massive star formation but more data is needed to further confirm our findings and draw statistically significant results.
molekylära moln, massiva stjärnor, stjärnhop, spektral energifördelning
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