Type: PIB

Indian researchers have found that SN 2010kd, a super-luminous supernova stands out with the amount of mass as well as Nickel ejected during explosion.

Space science-related terms these days are often focused on Gravitational waves, Black holes etc. But basic terminologies are very important and need to be taken care of. For example, a layman may hardly find any difference between Novae-Supernovae, Neutron star, Nebula etc. UPSC often tries to bust you with such basic differences.

What are Supernovae?

• Supernovae are kind of energetic explosions were the core of massive stars (a few times to that of the mass of our Sun) goes to a catastrophic phase of explosion liberating huge amounts of energy and mass.
• These events are visible through very far away distances much beyond our own solar system.
• Super-luminous supernovae are a special type of stellar explosions having energy output 10 or more times higher than that of standard supernovae.

What is so distinct about SN 2010kd?

• The mass ejection from SN 2010kd is metallic and is much more than seen in case of normal core-collapse supernovae.
• The scientists found that SN 2010kd exploded with a larger velocity but decayed slower than other similar supernovae.
• The observations show that parameters like rotation and metallicity play a crucial role in stellar explosions.

Indian researchers have discovered hundreds of Li-rich giant stars produced during BBN indicating that Li is being produced in the stars and accounts for its abundance in the interstellar medium.

Most of the space based theories and missions are focussed on the formation of our solar system. BBN is the most basic auxillary among them.

What is Big Bang Nucleosynthesis (BBN)?

• BBN is the production of nuclei other than those of the lightest isotope of hydrogen during the early phases of the Universe.
• Primordial nucleosynthesis is believed by most cosmologists to have taken place in the interval from roughly 10 seconds to 20 minutes after the Big Bang.
• It is calculated to be responsible for the formation of most of the universe’s helium in various isotopic forms.
• Essentially all of the elements that are heavier than lithium were created much later, by stellar nucleosynthesis in evolving and exploding stars.

Lithium in space

• Lithium (Li), is one of the three primordial elements, apart from Hydrogen and Helium (He), produced in the Big Bang Nucleosynthesis (BBN).
• However, the present measurement of Li in the interstellar medium and very young stars is about 4 times more than the primordial value.
• Thus, identifying sources of Li enrichment in our Galaxy has been a great interest to researchers to validate BBN as well as a stellar mixing process.
• In general, stars are considered as Li sinks. This means that the original Li, with which stars are born, only gets depleted over stars’ life-time as Li burns at relatively very low temperatures.

Researchers from the Indian Institute of Astrophysics (IIA), Bangalore have conducted the first systematic study on the gamma-ray flux variability nature on different types of Blazars.

Strange terminologies from space-based studies are very important from prelims point of view.  We can expect a statement based question seeking to identify the term which is being referred to in the paragraph.

What are Blazars?

• At the center of most galaxies, there’s a massive black hole that can have mass of millions or even billions of Suns that accrete gas, dust, and stellar debris around it.
• As these material falls towards the black hole, their gravitational energy gets converted to light forming active galactic nuclei (AGN).
• A minority of AGN (~15%) emit collimated charged particles called jets travelling at speeds close to the speed of light.
• Blazars are AGN whose jets are aligned with the observer’s line of sight.
• Some blazars are thought to host binary black holes in them and could be potential targets for future gravitational-wave searches.

Studying blazars

• Blazars are the most luminous and energetic objects in the known universe were found to be emitters of gamma-rays in the 1990s.
• It is only with the capability of Fermi Gamma-ray space telescope (launched in 2008) to scan the entire sky once in three hours one is able to probe the flux variability characteristics of blazars on a range of time scales.
• Gamma-ray band is one of the bands of the electromagnetic spectrum on which there is limited knowledge on the flux variability of blazars.
• Major problem while studying them is to localize the site for the production of gamma-rays.

Significance

• The study of blazars could provide clues to the processes happening close to the black hole, not visible through direct imaging.
• Exploring blazars will provide key inputs to constrain the high energy production site as well as the high energy emission processes.