Focus: GS III: Science and Technology
Why in News?
Scientists from SN Bose Centre for Basic Science (SNBCBS) observed the imploding novae called Nova V1280 Scorpii and found that a thick dust formed around it after a month and lasted for about 250 days.
About Novae
- A nova is an astronomical occurrence in which a powerful explosion temporarily increases the brightness of a star by hundreds to millions of times before gradually dimming over the course of weeks or months.
- It happens in a binary star system made up of a white dwarf and a main-sequence star, which is characterised by two stars orbiting a shared centre of mass.
- The primary star is the one that is brighter; the secondary star is the one that is fainter.
- White dwarf stars are those whose hydrogen nuclear fuel has been completely consumed.
- Such stars have very high density. A typical white dwarf is half the size of our Sun and has a surface gravity 1,00,000 times that of Earth.
What are the Findings?
- Scientists constructed simple models to estimate parameters of dust like hydrogen density, temperature, luminosity and elemental abundances during pre- and post-dust phase.
- High abundance of certain elements like carbon, nitrogen and oxygen was found along with a mixture of small amorphous carbon dust grains and large astrophysical silicate dust grains.
- Dust formation in novae ejecta is not a common phenomenon.
- It has been observed only in a few novae within 30 to 100 days after an outburst, as compared to interstellar dust, which typically takes a few thousand years to form and hence provided opportunity to study the dust formation process in novae.
- High abundance of isotopes of certain elements like carbon, nitrogen and oxygen was found in the predust phase.
- A mixture of small amorphous carbon dust grains and large astrophysical silicate dust grains present in the ejecta was found in the post dust phase.
- Some complex organic compounds like amorphous organic solids with a mixed aromatic–aliphatic structure was found which play an important role in formation of molecular clouds in stars and planets.
