A search of diffuse interstellar bands (DIBs) in planetary nebulae environment

Abstract

Diffuse Interstellar Bands (DIBs) are set of absorption features, mostly at optical and near infrared wavelengths, that are found in the spectra of reddened stars and other objects. DIBs are actively being investigated to understand the nature of their properties and carriers and also their roles in interstellar matter enrichment. Among of the proposed carriers is large carbonaceous molecules (fullerenes). Interestingly, such as C60 and C70 have been detected in Planetary Nebulae (PN) environment. This detection allows us to study DIBs in fullerene-rich space environment. In this work, we study the presence of DIBs in central star of planetary nebulae (CSPN) by using archival data of optical spectra observed with 8.1-m Gemini South Telescope and Gemini Multi-Object Spectrographs (GMOS, spectral range of 3900 Å - 5900 Å and resolution of R ∼ 2300) and also from 2.5-m Isaac Newton Telescope with IDS spectrograph (R ∼ 2300). We measured the equivalent width of 4430, 5870 and 6283 Å DIB by fitting the detected DIB profile with the empirical template derived from higher resolution data. We investigated 4430, 5870 and 6283 Å DIBs in the spectra of CSPN and their correlation with the colour excess (E(B-V)). The correlation between the DIB strength and E(B-V) has positive value. We found that the 4430 and 5870 Å DIBs are generally more abundant on the PN environment.