• Home
  • Tag: 上海419会所公司模特

Astronomers detect a doubly eclipsing quadruple star system

first_img More information: EPIC 219217635: A Doubly Eclipsing Quadruple System Containing an Evolved Binary, arXiv:1805.09693 [astro-ph.SR] arxiv.org/abs/1805.09693AbstractWe have discovered a doubly eclipsing, bound, quadruple star system in the field of K2 Campaign 7. EPIC 219217635 is a stellar image with Kp=12.7 that contains an eclipsing binary (`EB’) with PA=3.59470 d and a second EB with PB=0.61825 d. We have obtained followup radial-velocity (`RV’) spectroscopy observations, adaptive optics imaging, as well as ground-based photometric observations. From our analysis of all the observations, we derive good estimates for a number of the system parameters. We conclude that (1) both binaries are bound in a quadruple star system; (2) a linear trend to the RV curve of binary A is found over a 2-year interval, corresponding to an acceleration, γ˙=0.0024±0.0007 cm s−2; (3) small irregular variations are seen in the eclipse-timing variations (`ETVs’) detected over the same interval; (4) the orbital separation of the quadruple system is probably in the range of 8-25 AU; and (5) the orbital planes of the two binaries must be inclined with respect to each other by at least 25∘. In addition, we find that binary B is evolved, and the cooler and currently less massive star has transferred much of its envelope to the currently more massive star. We have also demonstrated that the system is sufficiently bright that the eclipses can be followed using small ground-based telescopes, and that this system may be profitably studied over the next decade when the outer orbit of the quadruple is expected to manifest itself in the ETV and/or RV curves. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Two sub-Jovian exoplanets orbiting bright stars discovered Citation: Astronomers detect a doubly eclipsing quadruple star system (2018, June 4) retrieved 18 August 2019 from https://phys.org/news/2018-06-astronomers-doubly-eclipsing-quadruple-star.html © 2018 Phys.org The Kepler exoplanet-hunting telescope lost its two reaction wheels in 2013. Its mission was repurposed, and is now known as K2. The main goal of the revived spacecraft is to perform high-precision photometry of selected fields in the ecliptic. So far, the K2 mission has detected over 300 extrasolar worlds and many new stellar systems.EPIC 219217635 was initially identified by K2 as a potential quadruple star system during the spacecraft’s Campaign 7, which took place in late 2015. Afterward, a team of astronomers led by Tamas Borkovits of the Baja Astronomical Observatory of Szeged University, Hungary, has conducted follow-up observations of this star, which included radial-velocity spectroscopy, adaptive optics imaging, as well as ground-based photometric observations.”In this work we report the discovery with NASA’s Kepler space telescope during Campaign 7 of its two-wheeled mission (hereafter referred to as ‘K2’) of a quite likely physically bound quadruple system consisting of two eclipsing binaries,” the researchers wrote in the paper.The astronomers found that EPIC 219217635, located some 2,800 light years away from the Earth, is composed of two eclipsing binaries with orbital periods of about 3.6 and 0.62 days. The binaries are most likely in a 20 AU orbit around each other.EPIC 219217635 A consists of a star about 20 percent larger and more massive than the sun, and its smaller companion – with a radius of 0.74 solar radii and a mass of 0.68 solar masses. The larger component is about 2.24 more luminous than the sun and has an effective temperature of 6,473 K. The smaller star is less luminous and cooler, with a luminosity of 0.19 solar luminosities and an effective temperature of 4,421 K.The primary star of EPIC 219217635 B is approximately 30 percent larger and more massive than our sun. It has an effective temperature of 6,931 K and a luminosity of 3.66 solar luminosities. When it comes to the secondary star, it is similar in size to the sun (1.04 solar radii) and has a mass of only 0.41 solar masses. Its effective temperature is 4,163 K and its luminosity was calculated to be about 0.29 solar luminosities.Additionally, the researchers found that EPIC 219217635 B is evolved, and in this binary cooler and currently less massive star has transferred much of its envelope to the currently more massive star.In concluding remarks, the astronomers noted that EPIC 219217635 is a promising target for future observations even with small telescopes.”The system is sufficiently bright that the eclipses can be followed using small ground-based telescopes, and that this system may be profitably studied over the next decade when the outer orbit of the quadruple is expected to manifest itself in the eclipse-timing variation and/or radial velocity curves,” the paper reads. Using NASA’s Kepler spacecraft, an international group of astronomers has discovered a doubly eclipsing, bound quadruple star system. The newly found system, designated EPIC 219217635, consists of stars similar in size to our sun, with masses ranging from 0.41 to 1.3 solar masses. The finding was presented May 24 in a paper published on arXiv.org. Explore further The disentangled and folded lightcurves of the 3.595-day ‘A’ binary and the 0.618-day ‘B’ binary (red dots). The black curves represent the disentangled, folded lightcurves, obtained from the simultaneous lightcurve solution. In the case of binary B the grey dots represent the sum of the disentangled, folded lightcurve and a simple model of the rotational spot modulation. The bottom panel for each binary shows the folded, disentangled residuals of the full K2 data from the model fit. Credit: Borkovits et al., 2018.last_img

Delhi dances with Stereo Nation

first_imgRemember Stereo Nation? The band which took the pop happy 90s by storm with their single Don’t Break my Heart? Well, one half of the band, Tarseme Singh Saini, better known as Taz, recently regaled collegegoers in the Capital when he performed at the annual cultural fest of a management college. The final day of the two-day festival Verve 2k13  saw the British-born pop singer charm the audience with his performance at the Rohini campus of the college. Also Read – ‘Playing Jojo was emotionally exhausting’The performance rounded off a fest that saw students showcase their creativity and talent in areas like tattoo art, quizzing, collage making, photography and singing. Students also organised a fashion show to display their tastes in accouterment, and also showcased their culinary talents. The event was attended by students from different campuses of the institute and for students who danced their way through the night, it was an evening to remember.Fest time was clearly a happy time for these kids.last_img read more

Dwarkanath Tagore bust unveiled in London

first_imgLondon: Prince Dwarkanath Tagore, best known for his significant role in the Bengal Renaissance of the 19th century, has been honoured with a new bust in London. The grandfather of Nobel laureate Rabindranath Tagore was among the first Indian industrialists, also known as merchant princes, investing in a range of businesses from steam engines to banking in the 1820s. He died during a visit to the UK in August 1846 and was buried at Kensal Green Cemetery in north-west London, where his bust was unveiled yesterday. Also Read – Rain batters Kolkata, cripples normal life “He was a Tagore who uplifted the face of trade and business long before his grandson Rabindranath Tagore received the Nobel Prize in Literature. He believed the sky’s the limit and his range of accomplishments spanned from coal, tea, jute, shipping, banking and the list can go on,” said Anirban Mukhopadhyay, President of London Sharad Utsav (LSU), among the groups behind the new statue. After decades amid thousands of other graves, LSU joined hands with the Bengal Heritage Foundation and with the support of the British Council, iLead (Kolkata), Friends of Kensal Green (London) launched the bust and a plaque marking Dwarkanath’s contributions. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killed Scores of people from the British Bengali community gathered for the event here. Kolkata-based businessman Pradeep Chopra travelled all the way from India with his family for the occasion. “I always wanted to break this fallacy that entrepreneurship is not for Bengalis and they are only meant to be doctors or professors. Entrepreneurship has been in the roots of Bengal since Dwarkanath’s era and some of the best entrepreneurs in the country can be from Bengal just like he was,” Chopra said. The ceremony was also marked by the presence of Saikat Maitra, Vice Chancellor of Maulana Abdul Kalam Azad University of Technology, who also flew in from India. “Emulation of corporate mindset and management of business by Dwarkanath needs to be presented in a more effective way before the next generation,” Maitra said. Dwarkanath died aged 52 at St. George’s Hotel in London during a major thunderstorm in the city. Britain’s then Queen, Victoria, and husband Prince Albert, who had welcomed him to their court like “an old friend” earlier, sent four carriages to the funeral for a so-called “princely” send-off. “Very few Indians are aware of Prince Dwarkanath Tagore’s tomb in London. From coal to banking to trading, he successfully set the foundation of an industrial Bengal and internationalisation of India,” said Sourav Nyogi, President of the Bengal Heritage Foundation, which spearheaded the project. “Our effort is a humble tribute to this great son of Bengal and to keep his heritage alive for the future generations,” he said.last_img read more