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Free Astronomy Magazine May-June 2020 cover EN.qxp_l'astrofilo 27/04/2020 16:36 Page 1 THE FREE MULTIMEDIA MAGAZINE THAT KEEPS YOU UPDATED ON WHAT IS HAPPENING IN SPACE Bi-monthly magazine of scientific and technical information ✶ May-June 2020 BBiioofflluuoorreesscceenntt ppllaanneetsts The star S2 moves according to Einstein’s Relativity Do sub-relativistic meteors exist? www.astropublishing.com ✶✶www.facebook.com/astropublishing [email protected] colophon EN_l'astrofilo 27/04/2020 16:36 Page 2 colophon EN_l'astrofilo 27/04/2020 16:36 Page 3 S U M M A R Y BI-MONTHLY MAGAZINE OF SCIENTIFIC AND TECHNICAL INFORMATION The star S2 moves according to Einstein’s Relativity FREELY AVAILABLE THROUGH Observations made with ESO’s Very Large Telescope (VLT) have revealed for the first time that a star or- THE INTERNET biting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein’s general theory of relativity. Its orbit is shaped like a rosette and not like an ellipse as predicted by... May-June 2020 4 Biofluorescent planets The closest potentially habitable rocky exoplanets all orbit around red dwarfs. These types of stars are particularly suitable for hosting Earth-sized planets, but they are also characterized by surface phenom- 10 ena very harmful to life as we know it. Some organisms, however, may be able to adapt to intense... ESO telescope observes exoplanet where it rains iron Researchers using ESO’s Very Large Telescope (VLT) have observed an extreme planet where they suspect it rains iron. The ultra-hot giant exoplanet has a day side where temperatures climb above 2400 degrees 22 Celsius, high enough to vaporise metals. Strong winds carry iron vapour to the cooler night side where... How newborn stars prepare for the birth of planets An international team of astronomers used two of the most powerful radio telescopes in the world to create more than three hundred images of planet-forming disks around very young stars in the Orion 24 Clouds. These images reveal new details about the birthplaces of planets and the earliest stages of star... English edition of the magazine lA’ STROFILO The best evidence for elusive mid-size black hole New data from the NASA/ESA Hubble Space Telescope have provided the strongest evidence yet for Editor in chief mid-sized black holes in the Universe. Hubble confirms that this “intermediate-mass” black hole dwells Michele Ferrara 28 inside a dense star cluster. Intermediate-mass black holes (IMBHs) are a long-sought “missing link” in... Scientific advisor Prof. Enrico Maria Corsini ALMA spots metamorphosing aged star Publisher Astro Publishing di Pirlo L. An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) Via Bonomelli, 106 captured the very moment when an old star first starts to alter its environment. The star has ejected 25049 Iseo - BS - ITALY high-speed bipolar gas jets which are now colliding with the surrounding material; the age of the... email [email protected] 32 Internet Service Provider Aruba S.p.A. Do sub-relativistic meteors exist? Via San Clemente, 53 24036 Ponte San Pietro - BG - ITALY Estimates produced from satellite data and extrapolations from meteor falls indicate that, every day, a few to a few hundred tons of dust and rock enter the Earth’s atmosphere from outer space. Nobody Copyright knows the precise amount, but it is assumed that all of that material formed in our own Solar System... All material in this magazine is, unless 34 otherwise stated, property of Astro Publishing di Pirlo L. or included with permission of its author. Reproduction or retransmission of the materials, in The strange orbits of ‘Tatooine’ planetary disks whole or in part, in any manner, with- Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found striking orbital out the prior written consent of the geometries in protoplanetary disks around binary stars. While disks orbiting the most compact binary copyright holder, is a violation of copy- star systems share very nearly the same plane, disks encircling wide binaries have orbital planes that are... right law. A single copy of the materi- 44 als available through this course may be made, solely for personal, noncom- mercial use. Users may not distribute such copies to others, whether or not The impact of satellite constellations on astronomical observations in electronic form, whether or not for Astronomers have recently raised concerns about the impact of satellite mega-constellations on scientific a charge or other consideration, with- research. To better understand the effect these constellations could have on astronomical observations, out prior written consent of the copy- ESO commissioned a scientific study of their impact, focusing on observations with ESO telescopes in... right holder of the materials. The 46 publisher makes available itself with having rights for possible not charac- terized iconographic sources. ALMA and Rosetta map the journey of phosphorus Advertising - Administration Phosphorus, present in our DNA and cell membranes, is an essential element for life as we know it. But Astro Publishing di Pirlo L. how it arrived on the early Earth is something of a mystery. Astronomers have now traced the journey Via Bonomelli, 106 of phosphorus from star-forming regions to comets using the combined powers of ALMA and the... 25049 Iseo - BS - ITALY 50 email [email protected] chronicles EN_l'Astrofilo 27/04/2020 16:39 Page 4 4 SPACE CHRONICLES The star S2 moves according to Einstein’s Relativity by ESO bservations made with ESO’s wards in the plane of motion. This Very Large Telescope (VLT) famous effect — first seen in the Ohave revealed for the first orbit of the planet Mercury around time that a star orbiting the super- the Sun — was the first evidence in massive black hole at the centre of favour of General Relativity. One the Milky Way moves just as pre- hundred years later we have now dicted by Einstein’s general theory detected the same effect in the mo- of relativity. Its orbit is shaped like tion of a star orbiting the compact a rosette and not like an ellipse as radio source Sagittarius A* at the predicted by Newton’s theory of centre of the Milky Way. This obser- gravity. This long-sought-after re- vational breakthrough strengthens sult was made possible by increas- the evidence that Sagittarius A* ingly precise measurements over must be a supermassive black hole nearly 30 years, which have enabled of 4 million times the mass of the scientists to unlock the mysteries of Sun,” says Reinhard Genzel, Direc- the behemoth lurking at the heart tor at the Max Planck Institute for of our galaxy. “Einstein’s General Relativity pre- his artist’s impression illustrates dicts that bound orbits of one object T the precession of the star’s orbit, with the effect exaggerated for eas- around another are not closed, as in ier visualisation. [ESO/L. Calçada] Newtonian Gravity, but precess for- MAY-JUNE 2020 chronicles EN_l'Astrofilo 27/04/2020 16:39 Page 5 SPACE CHRONICLES 5 MAY-JUNE 2020 chronicles EN_l'Astrofilo 27/04/2020 16:39 Page 6 6 SPACE CHRONICLES MAY-JUNE 2020 chronicles EN_l'Astrofilo 27/04/2020 16:39 Page 7 SPACE CHRONICLES 7 his simulation shows the orbits T of stars very close to the super- massive black hole at the heart of the Milky Way. One of these stars, named S2, orbits every 16 years and is passing very close to the black hole in May 2018. This is a perfect laboratory to test gravitational physics and specifically Einstein’s general theory of relativity. [ESO/L. Calçada/spaceengine.org] Extraterrestrial Physics (MPE) in Garching, Germany and the archi- tect of the 30-year-long pro- gramme that led to this result. Located 26 000 light-years from the Sun, Sagittarius A* and the dense cluster of stars around it provide a unique laboratory for testing physics in an otherwise unexplored and extreme regime of gravity. One of these stars, S2, sweeps in to- wards the supermassive black hole to a closest distance less than 20 bil- lion kilometres (one hundred and twenty times the distance between the Sun and Earth), making it one of the closest stars ever found in orbit around the massive giant. At its closest approach to the black hole, S2 is hurtling through space at almost three percent of the speed of light, completing an orbit once every 16 years. “After following the star in its orbit for over two and a half decades, our exquisite meas- urements robustly detect S2’s Schwarzschild precession in its path around Sagittarius A*,” says Stefan Gillessen of the MPE, who led the analysis of the measurements pub- lished today in the journal Astron- omy & Astrophysics. Most stars and planets have a non- circular orbit and therefore move closer to and further away from the object they are rotating around. S2’s orbit precesses, meaning that the location of its closest point to the supermassive black hole changes with each turn, such that MAY-JUNE 2020 chronicles EN_l'Astrofilo 27/04/2020 16:39 Page 8 his visible light wide-field view T shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the centre of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in in- frared images. This view was cre- ated from photographs in red and blue light and forming part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees.
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