January 2019 BRAS Newsletter
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Neutron Stars
Chandra X-Ray Observatory X-Ray Astronomy Field Guide Neutron Stars Ordinary matter, or the stuff we and everything around us is made of, consists largely of empty space. Even a rock is mostly empty space. This is because matter is made of atoms. An atom is a cloud of electrons orbiting around a nucleus composed of protons and neutrons. The nucleus contains more than 99.9 percent of the mass of an atom, yet it has a diameter of only 1/100,000 that of the electron cloud. The electrons themselves take up little space, but the pattern of their orbit defines the size of the atom, which is therefore 99.9999999999999% Chandra Image of Vela Pulsar open space! (NASA/PSU/G.Pavlov et al. What we perceive as painfully solid when we bump against a rock is really a hurly-burly of electrons moving through empty space so fast that we can't see—or feel—the emptiness. What would matter look like if it weren't empty, if we could crush the electron cloud down to the size of the nucleus? Suppose we could generate a force strong enough to crush all the emptiness out of a rock roughly the size of a football stadium. The rock would be squeezed down to the size of a grain of sand and would still weigh 4 million tons! Such extreme forces occur in nature when the central part of a massive star collapses to form a neutron star. The atoms are crushed completely, and the electrons are jammed inside the protons to form a star composed almost entirely of neutrons. -
Arxiv:2012.09981V1 [Astro-Ph.SR] 17 Dec 2020 2 O
Contrib. Astron. Obs. Skalnat´ePleso XX, 1 { 20, (2020) DOI: to be assigned later Flare stars in nearby Galactic open clusters based on TESS data Olga Maryeva1;2, Kamil Bicz3, Caiyun Xia4, Martina Baratella5, Patrik Cechvalaˇ 6 and Krisztian Vida7 1 Astronomical Institute of the Czech Academy of Sciences 251 65 Ondˇrejov,The Czech Republic(E-mail: [email protected]) 2 Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, 119234, Moscow, Russia 3 Astronomical Institute, University of Wroc law, Kopernika 11, 51-622 Wroc law, Poland 4 Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotl´aˇrsk´a2, 611 37 Brno, Czech Republic 5 Dipartimento di Fisica e Astronomia Galileo Galilei, Vicolo Osservatorio 3, 35122, Padova, Italy, (E-mail: [email protected]) 6 Department of Astronomy, Physics of the Earth and Meteorology, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynsk´adolina F-2, 842 48 Bratislava, Slovakia 7 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, H-1121 Budapest, Konkoly Thege Mikl´os´ut15-17, Hungary Received: September ??, 2020; Accepted: ????????? ??, 2020 Abstract. The study is devoted to search for flare stars among confirmed members of Galactic open clusters using high-cadence photometry from TESS mission. We analyzed 957 high-cadence light curves of members from 136 open clusters. As a result, 56 flare stars were found, among them 8 hot B-A type ob- jects. Of all flares, 63 % were detected in sample of cool stars (Teff < 5000 K), and 29 % { in stars of spectral type G, while 23 % in K-type stars and ap- proximately 34% of all detected flares are in M-type stars. -
Commonwealth of Australia Gazette ASIC 16/02, Tuesday, 9 April 2002
= = `çããçåïÉ~äíÜ=çÑ=^ìëíê~äá~= = Commonwealth of Australia Gazette No. ASIC 16/02, Tuesday, 9 April 2002 Published by ASIC ^^ppff``==dd~~òòÉÉííííÉÉ== Contents Notices under the Corporations Act 2001 00/2496 01/1681 01/1682 02/0391 02/0392 02/0393 02/0394 02/0395 02/0396 02/0397 02/0398 02/0399 02/0400 02/0401 02/0402 02/0403 02/0404 02/0405 02/0406 02/0408 02/0409 Company deregistrations Page 43 Change of company status Page 404 Company reinstatements Page 405 ISSN 1445-6060 Available from www.asic.gov.au © Commonwealth of Australia, 2001 Email [email protected] This work is copyright. Apart from any use permitted under the Copyright Act 1968, all rights are reserved. Requests for authorisation to reproduce, publish or communicate this work should be made to: Gazette Publisher, Australian Securities and Investment Commission, GPO Box 5179AA, Melbourne Vic 3001 Commonwealth of Australia Gazette ASIC Gazette ASIC 16/02, Tuesday, 9 April 2002 Company deregistrations Page 43= = CORPORATIONS ACT 2001 Section 601CL(5) Notice is hereby given that the names of the foreign companies mentioned below have been struck off the register. Dated this nineteenth day of March 2002 Brendan Morgan DELEGATE OF THE AUSTRALIAN SECURITIES AND INVESTMENTS COMMISSION Name of Company ARBN ABBOTT WINES LIMITED 091 394 204 ADERO INTERNATIONAL,INC. 094 918 886 AEROSPATIALE SOCIETE NATIONALE INDUSTRIELLE 083 792 072 AGGREKO UK LIMITED 052 895 922 ANZEX RESOURCES LTD 088 458 637 ASIAN TITLE LIMITED 083 755 828 AXENT TECHNOLOGIES I, INC. 094 401 617 BANQUE WORMS 082 172 307 BLACKWELL'S BOOK SERVICES LIMITED 093 501 252 BLUE OCEAN INT'L LIMITED 086 028 391 BRIGGS OF BURTON PLC 094 599 372 CANAUSTRA RESOURCES INC. -