Free Astronomy Magazine November-December 2015

Editor in chief Michele Ferrara Scientific advisor Prof. Enrico Maria Corsini Publisher Astro Publishing di Pirlo L. Via Bonomelli, 106 25049 Iseo - BS - ITALY email info@astropublishing.com Internet Service Provider Aruba S.p.A. Loc. Palazzetto, 4 52011 Bibbiena - AR - ITALY Copyright All material in this magazine is, unless otherwise stated, property of Astro Publishing di Pirlo L. or included with permission of its author. Reproduction or retransmission of the materials, in whole or in part, in any manner, with- out the prior written consent of the copyright holder, is a violation of copyright law. A single copy of the materials available through this course may be made, solely for personal, non- commercial use. Users may not distrib- ute such copies to others, whether or not in electronic form, whether or not for a charge or other consideration, without prior written consent of the copyright holder of the materials. The publisher makes available itself with having rights for possible not characterized iconographic sources. Advertising - Administration Astro Publishing di Pirlo L. Via Bonomelli, 106 25049 Iseo - BS - ITALY email admin@astropublishing.com ASTROFILO l’ November-December 2015 BI-MONTHLY MAGAZINE OF SCIENTIFIC AND TECHNICAL INFORMATION FREELY AVAILABLE THROUGH THE INTERNET English edition of the magazine S U M M A R Y Even today there is liquid water on Mars That in a more or less remote past Mars hosted liquid water is well known for some time. But only a hydrological system that is still active today could support any form of indigenous life and facilitate the exploration of the planet by terrestrial “aliens”. Now we have the certainty that, although sparingly... 4 VLT finds hottest and most massive touching double star The double star system VFTS 352 is located about 160,000 light-years away in the Tarantula Nebula (the star’s name indicates that it was observed as part of the VLT FLAMES Tarantula Survey). This re- markable region is the most active nursery of new stars in the nearby Universe and new observations... 12 Revisiting the Veil Nebula Deriving its name from its delicate, draped filamentary structures, the beautiful Veil Nebula is one of the best-known supernova remnants. It formed from the violent death of a star twenty times the mass of the Sun that exploded about 8000 years ago. Located roughly 2100 light-years from Earth in the... 16 Mysterious ripples found racing through planet-forming disc AU Microscopii, or AU Mic for short, is a young, nearby star surrounded by a large disc of dust. The disc essentially comprises asteroids that have collided with such vigour that they have been ground to dust. Studies of such debris discs can provide valuable clues about how planets, which form from these discs... 18 VISTA discovers new component of Milky Way The Vista Variables in the Vía Láctea Survey (VVV) ESO public survey is using the VISTA telescope at the Paranal Observatory to take multiple images at different times of the central parts of the galaxy at in- frared wavelengths. It is discovering huge numbers of new objects, including variable stars, clusters... 22 Exploring asteroids and comets using “hedgehogs” The rough surface of asteroids and comets makes it impossible to explore and study them with traditio- nal rovers, implying the need for a completely new technical solution. JPL/NASA, Stanford University and the MIT have recently tested the one that seems the most feasible alternative, a small cube-shaped... 24 The nearest quasar is powered by a double black hole Astronomers using NASA's Hubble Space Telescope have found that Markarian 231 (Mrk 231), the near- est galaxy to Earth that hosts a quasar, is powered by two central black holes furiously whirling about each other. The finding suggests that quasars — the brilliant cores of active galaxies — may commonly... 30 NASA's Hubble finds supernovae in 'wrong place at wrong time' Scientists have been fascinated by a series of unusual exploding stars-outcasts beyond the typical cozy confines of their galaxies. A new analysis of 13 supernovae — including archived data from NASA's Hubble Space Telescope — is helping astronomers explain how some young stars exploded sooner... 34 New Hubble image of the Twin Jet Nebula The cosmic butterfly pictured in this NASA/ESA Hubble Space Telescope image goes by many names. It is called the Twin Jet Nebula as well as answering to the slightly less poetic name of PN M2-9. The M in this name refers to Rudolph Minkowski, a German-American astronomer who discovered the nebula... 38 Discovered the first Dyson sphere? In the constellation Cygnus there is an apparently normal star that over a period of a couple of years has shown two inexplicable dips in brightness. No known natural phenomenon seems to be at the ori- gin of this abnormal behaviour and there is someone who does not exclude that the cause should be... 42