21 June 2020: PIB Summary & Analysis

June 21st, 2020 PIB:- Download PDF Here

TABLE OF CONTENTS

1. UNICEF Kid Power
2. International Day of Yoga
3. Pokhran potteries
4. Stellar evolution in the Milky Way Galaxy
5. Extreme Helium Stars
6. Black Holes and Gravitational Waves

1. UNICEF Kid Power

Context:

‘UNICEF Kid Power’  has listed 13 Yoga stretches and poses for children.

About UNICEF Kid Power:

• UNICEF Kid Power is a program of UNICEF USA that gives kids the power to save lives by connecting their everyday activity to real-world impact.
• Launched in 2015, the initiative, in collaboration with technology firms, develops activity tracker bands for kids.
• These bands act as a kids’ fitness tracker bracelet that connects to a smartphone app. The app lets users complete missions, which counts total steps and awards points.
• The points then unlock funding from partners, which is then used by UNICEF to deliver packets of therapeutic food (Ready-to-use Therapeutic Food (RUTF)) to severely malnourished children around the globe.

2. International Day of Yoga

Context:

International Day of Yoga or Yoga Day was observed on 21^st June. This year saw the 6^th annual celebration.

To know more about Yoga Day, check PIB dated June 9, 2020.

3. Pokhran potteries

Context:

KVIC starts reviving ancient glory of Pokhran potteries.

Details:

• The Khadi and Village Industries Commission (KVIC) distributed 80 electric potter wheels to 80 potter families in Pokhran which has a rich heritage in terracotta products.
• Pokhran, in Jaisalmer district of Rajasthan, has over 300 potters’ families that have been engaged with pottery for several decades, but potters had started looking for other avenues due to heavy drudgery in the work and no market support.
• Apart from the electric wheels, the KVIC also distributed 8 blunger machines, used for mixing the clay which can produce 800 kg clay in just 8 hours. Manually it takes 5 days to prepare 800 kg mud for pottery making.
• The 80 potters were also given 15-days’ training to help them come up with exquisite pottery.

About Rajasthan potteries:

• Rajasthan is famous for terracotta items. Diverse forms of pottery are made in different regions of Rajasthan.
• Alwar is known for producing paper-thin Kagazi pottery, while Pokhran is renowned for white and red clay articles with geometric designs. Bikaner is home to painted pottery, tinted with lac colours. Jaisalmer is famous for stoneware pottery.
• Rajasthan is also known for its Blue Pottery.
  • Turko-Persian in origin, the art of blue pottery is said to have flourished in Jaipur under the 19^th century ruler Maharaja Ram Singh II.
  • The special feature of blue pottery is that, unlike others, it is made of ground quartz stone and clay is not used at all. The traditionally used colours are blue (extracted from oxide of cobalt), green (from the oxides of copper) and white.
  • Some pottery is semi translucent and in addition to the traditional colours, other combinations have now been evolved, such as canary yellow, dark blue and brown.
  • The conventional designs are floral or arabesque patterns, sometimes with figures of animals.

4. Stellar evolution in the Milky Way Galaxy

Context:

Study showing stars of varied ages can co-exist in open clusters, provides clue to stellar evolution in the Milky Way Galaxy.

Details:

• Stars in the Milky Way Galaxy are formed from the molecular clouds present in the galaxy.
• Star clusters are important clues to understand the mechanism of star formation because it is believed that a majority of stars in the Milky Way are formed in star clusters.
  • Star clusters are groups of stars which are gravitationally bound.
  • Open star clusters are a system of stars bound by gravity in which stars are born from the same molecular clouds.
  • All the stars in a cluster follow the evolutionary sequence as per their initial masses at the time of formation of these stars.
  • Open clusters are also important in probing the formation and evolution of the Milky Way Galaxy as they are distributed throughout the Galactic disk.
• Astronomers at the Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous science institute under the Department of Science and Technology (DST) Govt. of India, have found that stars of varied ages can co-exist in open clusters. This challenges earlier understanding that stars in an open cluster have the same age.
• The scientists measured the light from three poorly studied open clusters NGC 381, NGC 2360, and Berkeley 68 (observed using the 1.3-m telescope at Devasthal Observatory situated in Nainital) for studying the evolution of stars in these clusters.
  • They found two different stellar evolutionary sequences in the cluster NGC 2360, which has been observed in very few open clusters in the Milky Way Galaxy until now.
• Other than the stellar evolution, the researchers also studied the dynamical evolution of these clusters for the first time.
  • The mass distributions of stars belonging to the clusters have shown the preferential distribution of massive stars in the inner part of the clusters while low mass stars are found towards outer region of the clusters.
• It is believed that some of the very low mass stars have in fact, left their parent clusters and may be roaming as a free star like our own Sun.
• Their study lent important insight about the stellar and dynamical evolution of these clusters.

5. Extreme Helium Stars

Context:

Detection of fluorine in hot Extreme Helium Stars solves their evolution mystery.

What is an Extreme Helium Star?

• An extreme helium star or EHe is a low-mass supergiant that is almost devoid of hydrogen, the most common chemical element of the universe.
• There are 21 of them detected so far in our galaxy.
• The origin and evolution of these Hydrogen deficient objects have been shrouded in mystery.
• Their severe chemical peculiarities challenge the theory of well-accepted stellar evolution as the observed chemical composition of these stars do not match with that predicted for low mass evolved stars.

The study:

• A study by the Indian Institute of Astrophysics (IIA), an autonomous institute of the DST, which detected the presence of singly ionised fluorine for the first time in the atmospheres of hot Extreme Helium Stars makes a strong case that the main formation of these objects involves a merger of a carbon-oxygen (CO) and a Helium (He) white dwarf.
• The research published in the Astrophysical Journal which showed fluorine abundances determined from singly ionized fluorine (F II) lines, suggest a very high enrichment of fluorine, about a factor of 100 to 10000 times higher than normal stars.
• Clues to evolution of extreme helium stars require accurate determinations of their chemical composition, and the peculiarities, if any, become very important. Fluorine plays a very crucial role in this regard to determine the actual evolutionary sequence of these hydrogen deficient objects.
• Severe fluorine enrichment w.r.t normal stars was observed in the cool EHes along-with the cooler classical hydrogen deficient stars, the RCB variables (R Coronae Borealis Stars) hinting at close evolutionary connection between them.
• By comparing the observed fluorine abundances with other abundances of the key elements, the scientists could determine the formation channels responsible for fluorine enrichment.
• The varied range of observed fluorine abundance across stars having similar atmospheric parameters points out the difference in the individual star’s evolution and the ensuing nucleosynthesis.
• Particularly, the enrichment of fluorine in the atmospheres of carbon-rich EHes and absence of the same in carbon-poor EHes suggest that fluorine is profusely produced during the merger of a He-CO WD resulting in a carbon-rich EHe, whereas He-He WD merger that results in carbon-poor EHes does not account for fluorine overabundance.
• The detection of enhanced fluorine abundances in the atmospheres of hot EHes solves a decade-old mystery about their formation.
• It firmly places hot EHes in an evolutionary sequence with cool EHes and other hydrogen-deficient stars, and zeros in on the evolutionary scenario, which involves the merger of two double degenerate white dwarfs (WDs).

6. Black Holes and Gravitational Waves

Context:

IACS Kolkata INSPIRE faculty’s work on Black Holes and Gravitational Waves to help understanding fundamentals of our nature.

About Black Holes:

• A black hole refers to a point in space where matter is so compressed as to create a gravity field from which even light cannot escape.
• It is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it.
• Albert Einstein’s theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.
• The term ‘black hole’ was coined by American Physicist John Archibald Wheeler in the 1960s.
• The boundary of the region from which no escape is possible is called the event horizon.
• A black hole acts like an ideal black body, as it reflects no light.
• Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings.
• Black hole binaries emit gravitational waves during their in-spiral, merger, and ring-down phases.
  • A binary black hole is a system consisting of two black holes in close orbit around each other.

To know more about Gravitational Waves, click on the linked article.

June 21st, 2020 PIB:- Download PDF Here

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