STUDY OF DUST PROPERTIES AROUND HELIX NEBULA(NGC–7293) USING IRIS, AKARI, WISE SURVEYS, AND 2-DUST MODEL

Abstract

The present study aims to investigate the properties of the dust around Helix Nebula (NGC 7293) using IRIS, AKARI, and WISE surveys and the 2-Dust model. Helix Nebula is one of the well-known planetary nebulae in our Milky Way Galaxy. The study objectives include examining the dust color temperature, dust mass distribution, distribution of flux, and Jean’s criteria of the nebula, producing dust color temperature and dust mass maps of the field, and determining the mass loss rate, luminosity, inner shell radius, outer shell radius, and other dust properties of Helix Nebula using a density distribution function and comparing them to another model. The methodology employed includes using 2-Dust code, Aladin v10.0, and Python 3.7. The FITS image was taken from Sky View Virtual Observatory. The study findings indicate that the relative flux density is maximum around the central region and minimum around the outer region at F100 𝜇m and F22 𝜇m FITS images. The dust particle that emits a flux of 140 𝜇m is minimum in the central region. The dust color temperature of Helix Nebula varies depending on the survey used, with an average dust color temperature of (28.930 ± 0.005) K for the IRIS survey, (24.440 ± 0.078) K for the AKARI survey, and (277.490 ± 0.001) K for the WISE survey. The study also found that the dust color temperature was higher in the WISE survey than in the IRIS and AKARI surveys, suggesting an inverse relationship between the dust color temperature and the wavelength. The dust mass value was found to be higher in the AKARI survey and lower in the WISE survey. The calculated dust mass of Helix nebula using IRIS, AKARI, and WISE survey was found to be 0.10 M⊙, 0.56 M⊙, and 0.034 M⊙ respectively. The estimated dust mass in the circumstellar shell was 0.051 M⊙ and the mass loss rate was found to be 1.04×10−5 M⊙ yr−1 using the axisymmetric model. The study concludes that the results obtained from the 2- Dust code as well as the IRIS, AKARI, and WISE surveys provide a better understanding of the properties of dust around Helix Nebula.