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Indian researchers’ breakthrough in blue stragglers’ formation

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New Delhi, Sep 3: Indian researchers have found that half of the blue stragglers in their sample are formed through mass transfer from a close binary companion star, one third are likely formed through collisions of two stars, and the remaining are formed through interactions of more than two stars.

Blue stragglers, a class of stars on open or globular clusters that stand out as they are bigger and bluer than the rest of the stars, have intrigued scientists who have for long probed their origin.

A bunch of stars born at the same time from the same cloud form a star cluster. As time passes, each star evolves differently depending on its mass. The most massive and bright stars evolve and move off the main sequence creating a bend in their track, known as the turnoff, a release from the Ministry of Science and Technology said on Thursday.

Stars above this bend or brighter and hotter stars are not expected in a cluster, as they leave the main sequence to become red giants. But in 1953, Allan Sandage found that some stars seem to be hotter than the turnoff of the parent cluster. Initially, these blue stars still straggling above the turnoff were not part of these clusters. However, later studies confirmed that these stars are indeed cluster members, and they were termed “Blue Stragglers”.

Carrying out the first-ever comprehensive analysis of blue stragglers, the researchers said, the only probable way these stars can still be present in these clusters is if they have somehow acquired extra mass along the way while on the main sequence.

Confirming the mechanisms of the mass gain required a study using a large sample of blue-straggler stars and estimates of the mass they have gained.

Vikrant Jadhav and his PhD supervisor, Annapurni Subramaniam from the Indian Institute of Astrophysics (IIA), utilised the Gaia telescope launched in 2013 by the European Space Agency with its excellent positional accuracy to select the blue stragglers in clusters and understand how many such stars there are, where they are and how they are formed, the release said.

They found that among the clusters they scanned, 228 have a total of 868 blue stragglers. This first-ever comprehensive analysis of blue stragglers is published in the journal Monthly Notices of the Royal Astronomical Society. It showed that these stars are primarily present in the older and massive star clusters. And due to their large mass, they are segregated towards the centre of the clusters.

The researchers compared the mass of the blue stragglers to the mass of the turnoff stars (which are the most massive ‘normal’ stars in the cluster) and predicted the formation mechanisms, the release said.

Jadhav, the PhD student who led the work, said: “Overall, we found that more than 54 per cent of blue stragglers are formed through mass transfer from a close binary companion star, and 30 per cent of the blue stragglers are likely formed through collisions of two stars. Interestingly, 10-16 per cent of the blue stragglers are formed through interactions of more than two stars”.

The study will help improve understanding of these stellar systems to uncover exciting results in studies of large stellar populations, including galaxies. Following these findings, the researchers are conducting detailed analyses of individual blue stragglers in the catalogue to obtain their stellar properties.

Furthermore, interesting clusters and blue stragglers identified in this study will be followed up with ultraviolet imaging with Ultra-Violet Imaging Telescope on AstroSat, India’s first dedicated space observatory, as well as the 3.6 m Devasthal Optical Telescope in Nainital, the release added.

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Call me “Dada”, not “Sir”, Tripura CM Biplab Kumar Deb to employees

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Agartala: In what appears to be a step to boost the morale of the government employees, Chief Minister Biplab Kumar Deb on Sunday asked the government employees to call him “Dada” instead of “Sir”. “Call me Dada, not sir. It enhances the warmth of the relationship”, Deb told a gathering of government employees.

Deb exhorted the government employees of the state especially ASHA and Anganwadi workers of the state asking them not to dishearten as the state government was eager to improve their pay structure.

“I salute the ASHA and Anganwadi workers of my state. The level of dedication that my sisters have shown during the pandemic period deserved applause. I know, they want to hear good news from me and I am assuring you all that this government will not disappoint anyone”, Chief Minister Biplab Kumar Deb told a gathering of government employees at Badharghat sports school field organized by Vivekananda Vicha Manch (VVM).

VVM has emerged as a big platform of government employees, of late, and Sunday’s public rally was its first big gathering to thank the Chief Minister for the series of steps his government took for the welfare of the employees.

“I know what challenges you people are facing. Nothing is hidden in front of me. I am assuring you all everything will be taken care of in the due course of time”, he added.  Lauding the efforts of government employees Deb said, without them no government office can function.

“Due to the efforts of government employees, people can access the benefits of the state sponsored welfare schemes. But, for a prolonged period the employees did not get their right to do something freely. They were trapped in the clutches of unions. In the previous regime, Left sponsored unions used to enjoy supreme power which had reduced the whole work culture of the state to tatters. In 2018, you people showed courage and voted BJP to power”, said Deb.

“Despite fund constraints, the state government is positively working on the issues of DA and other factors pertaining to the interest of the government employees. Our government has already addressed a number of issues related to financial benefits. The ad-hoc promotion, increment for Group D, Group C employees, regularization of SSA teachers, seventh pay scale, UGC scale for professors, special benefit for LTC are to name a few. All these indicate what we want to do and we shall do what we promise”, the Chief Minister said.

The Chief Minister also asked the officials not to call him “sir” suggesting them to refer to him as “Dada” as it makes the relationship stronger and cherished. The Chief Minister also distributed clothes among children of Badharghat sports school during the programme. State BJP President Manik Saha, Minister Ram Prasad Paul, Minister Sushanta Chowdhury, MLA Mimi Majumder, state BJP Vice President and president of Vivekananda Vichar Manch Rajib Bhattacharjee also spoke on the occasion.

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MoS home’s son Ashish Mishra sent to judicial custody for 14 days

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Lakhimpur: Son of Union Minister of State for Home Ajay Mishra, Ashish Mishra, was produced before a court here late on the night of October 9, 2021, which sent him to 14-day judicial custody in connection with the October 3 Lakhimpur violence.

After around 12 hours of questioning in connection with the violence in which eight persons including four farmers were killed, a medical team examined Ashish Mishra in the crime branch office, after which he was taken for production before a judicial magistrate, who sent him to custody, senior prosecution officer SP Yadav.

He said an application for police remand of Ashish Mishra was submitted to the judicial magistrate who fixed it for hearing at 11 AM on October 11, 2021. Ashish Mishra was named in an FIR following allegations that he was in one of the vehicles that mowed down four farmers protesting over UP Deputy Chief Minister Keshav Prasad Maurya’s visit last Sunday.

Farmer leaders and opposition parties had been demanding Mishra’s arrest but the minister and his son had denied the allegations.
Two BJP workers and their driver were allegedly lynched by angry farmers in the incident. Local journalist Raman Kashyap also died in the violence, which has triggered a political storm and put the BJP government on the back foot in poll-bound Uttar Pradesh.

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Mayawati questions the Congress on the killing of Dalit in Rajasthan

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Lucknow: Selective outrage of the Congress is always criticised and Bahujan Samaj Party chief Mayawati on October 10, 2021 took on the Congress and termed as “condemnable” the incidence of a Dalit person being beaten to death in Rajasthan’s Hanumangarh. The former chief minister of Uttar Pradesh questioned the silence of the Congress.

A Dalit man was allegedly beaten to death on October 7, 2021 by a group of men in Hanumangarh over his love affair, the Rajasthan police said. Three people have been detained in connection with the case on Saturday. There are several such cases on which the Congress keep blind eye.

Mayawati said: “Will the Chief Ministers of Chhattisgarh and Punjab go there and give Rs 50 lakh to the victim’s family? The BSP demands an answer, otherwise it should stop shedding crocodile tears in the name of the Dalits.”

On the Lakhimpur Kheri violence, she tweeted, “The cropping up of the name of the son of the Union minister in the Lakhimpur violence raises questions on the working style of the BJP government.” The BJP should sack the minister as only then will there be any hope of justice for the aggrieved farmers, she added.
Mayawati also said terrorists are killing innocent people almost everyday in Jammu and Kashmir, which is very sad and shameful. The BSP demands that the Centre should take some strong steps in this regard.

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