Abstract

Contributed Talk - Splinter MassiveStars

Tuesday, 10 September 2024, 15:40   (S23)

Testing the bloated star hypothesis in IRAS 19520+2759

Rakesh Pandey, AIna Palau
Instituto de Radioastronom ́ıa y Astrof ́ısica, Universidad Nacional Aut ́onoma de M ́exico

Although several theoretical and observational works have shed light on the formation process and the initial evolution of massive stars (M > 8 M⊙), the details of these processes are far from completely understood. Massive stars are thought to be formed from their protostellar seeds, accreting at a rate of > 10−4 M⊙ yr−1. An important aspect robustly predicted by theory is that protostars accreting at high accretion rates (≳ 10−4 M⊙ yr−1) should bloat or swell up. IRAS 19520+2759 is a candidate O-type 'bloated star' proposed by Palau et al. (2013). Using observed optical time series data, Gaia, and NEOWISE archival data sets, we performed a variability study on the candidate bloated MYSO IRAS 19520+2759. This is the first time that a bloated star candidate has been tested for the theoretically predicted periodic variability. The association between the millimetre-dense core and the optical star remains to be confirmed; hence, we further performed a 0.15-arcsec angular resolution study of the continuum at 1 mm from ALMA in order to determine the position and morphology of the mm source. Simultaneously, from the spectral line observations of dense gas tracers, we investigated the kinematics of the gas in the vicinities of the first O-type 'bloated star' candidate.