Affiliation: CHRIST (Deemed to be University), Bangalore
Conference ID : ASI2022_71
Title : Discovery of fullerenes in the circumstellar medium of Herbig Ae/Be stars
Authors : Arun Roy, Blesson Mathew, P. Manoj, Maheswar Gopinathan, Mayank Narang, Shridharan Baskaran
Abstract Type: Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : Buckminsterfullerene (C_60) is one of the most stable cage-like carbonaceous molecules, which exist in space. The molecule is identified commonly around evolved stars and rarely in the young star formation regions. We report the survey and discovery of C_60 (buckminsterfullerene) in the circumstellar medium of six Herbig Ae/Be stars and the reflection nebulae NGC 2245 using archival Spitzer IRS low resolution spectra. The two prominent infrared vibrational modes of C60 bands at 17.4 μm and 18.9 μm are detected in the spectra of the seven sources. In the case of two Herbig Ae/Be stars, we report the tentative evidence of C_60 emission originating from the circumstellar disk. The continuum spectral index analysis and the comparison with known C_60 sources indicated that there exist two different type of emission patterns among the sample of stars. The spectra of four Herbig Ae/Be stars resemble that of reflection nebulae and their association with previously known refection nebulae are confirmed. These spectra are dominated by envelope emissions confirming the origin of C_60 emission to be from the reflection nebulae. The remaining two spectra show similarities with known C_60 emitting planetary nebulae. The major difference being with the absence of forbidden lines in the spectra of HAeBe stars. These spectra are dominated by disk emission, which is suggestive of circumstellar disk origin for C_60 in these stars.