Introduction

This is a final year Bachelor's project on stellar astrophysics aimed at studying the properties of isolated dust structures around the white dwafs using IRIS (60 μm and 100 μm), AKARI (90 μm and 140 μm), and WISE (12 μm and 22 μm) data. These properties include dust color temperature, dust mass, IR flux density, inclination angle, visual extinction, spectral emissivity and Jeans mass.

The radiation from ISM dust, confined within the molecular clouds, is the source of emissions from very cold objects: typically less than 140 K. These dust structures obscure relatively nearby regions in visible and UV regions and re-radiate the absorbed radiation in the FIR region. This contributes a major part (30%) of the total luminosity of the galaxy. These FIR radiations preponderate over the gravitational energy of collapsing clouds, instigating star formations. Moreover, dust structures being responsible for the molecular dissociation and successively resulting H₂ molecule formation site, are crucial in studying the chemistry of ISM. Constituting most of the elements contributing to the cooling process, dust also controls the temperature of the ISM. On the other hand, it provides heat through electrons-photo-electrically ejected from the grains i.e. cold emission of electrons. Such dust structures are pivotal in the study of interaction phenomena in the ISM.

Publications

1. S. Rijal, S. Sigdel, and M.S. Paudel, (2022), Study of an Isolated Dust Structure Nearby the White Dwarf WD0011-399 Using IRIS, AKARI, and WISE Data, Special Issue of Journal of Nepal Physical Society (JNPS), 8(2), pp.14–22.

2. S. Sigdel, S. Rijal, and M.S. Paudel, (2022), Comparative Study of Dust Properties around White Dwarf PG1225-079 in IRIS, AKARI AND WISE Data, Journal of Nepal Physical Society (JNPS), 8(3), pp.79–92.

3. Poster submitted at IAU Symposium 366: The Origin of Outflows in Evolved Stars. S. Rijal, and M.S. Paudel, (2022), Study of Dust Properties Around the White Dwarf GD 61 in IRIS and AKARI Maps

The full version of the thesis is also publicly available at ResearchGate.

Citations

Please cite our work as follows for any purpose of usage.

@article{rijal2022study,
  title={Study of an Isolated Dust Structure Nearby the White Dwarf WD0011-399 Using IRIS, AKARI, and WISE Data},
  author={Rijal, S and Sigdel, S and Paudel, MS},
  journal={Journal of Nepal Physical Society},
  volume={8},
  number={2},
  pages={14--22},
  year={2022}
}

@article{sigdel2022comparative,
  title={Comparative Study of Dust Properties around White Dwarf PG 1225-079 in IRIS, AKARI and WISE Data},
  author={Sigdel, S and Rijal, S and Paudel, MS},
  journal={Journal of Nepal Physical Society},
  volume={8},
  number={3},
  pages={79--92},
  year={2022}
}