Discovery of lithium in a stellar explosion
- Nature publishes new observational findings today that confirm a theory by scientists from Institut de Ciències de l’Espai (CSIC-IEEC).
Black hole gamma-ray lightning
The MAGIC telescopes at La Palma have recorded the fastest gamma-ray flares seen to date, produced in the vicinity of a super-massive black hole. The scientists explain this phenomenon by a mechanism similar to that producing lightning in a storm. This result, with an important Spanish contribution, is published today in Science. In the night from 12 to 13 November 2012, the MAGIC gamma-ray telescopes, in the Observatorio del Roque de los Muchachos, were observing the Perseus cluster of galaxies (at a distance of about 260 million light-years) when they detected this extraordinary phenomenon coming from one of the galaxies in the cluster, known as IC310. As many other galaxies, IC310 hosts in its center a super-massive black hole of several million times the mass of the Sun, which sporadically produces intense gamma-ray flares. On this occasion, however, the scientists were astonished by the brevity of the flares, lasting only for a few minutes. “Relativity tells us that no object can emit for a time shorter than it takes light to cross it. We know that the black hole in IC310 has a size of about 20 light-minutes, approximately three times the distance between the Earth and the Sun. This means that the black hole cannot produce a flare shorter than 20 minutes”, says Julian Sitarek, a Juan de la Cierva researcher at IFAE (Barcelona), and one of the three leading scientists of this work. However, the flares observed in IC310 lasted for less than 5 minutes. The scientists of the MAGIC Collaboration propose a new mechanism, according to which this “gamma-ray storm” is produced in the vacuum regions created close to the black hole magnetic poles. Very intense electric fields appear in these regions, and are destroyed when they are filled again with charged particles. These particles are accelerated up to close the speed of light, subsequently transferring part of their energy to the photons they find in their way, thus converting them into gamma rays. The time needed for the light to cross one of these vacuum regions is of a few minutes, in agreement with the observations of IC310. “It is similar to what happens in an electric storm”, explains Oscar Blanch, Ramón y Cajal researcher at IFAE, and Co-Spokesman of the MAGIC Collaboration. “The potential difference is so large that it ends up discharging into a lightning”. In this case, the discharge reaches the highest energies observed in nature, and produces gamma rays. The black hole appears to be immersed in a storm of colossal proportions. Up until now, the gamma ray emissions from galaxies such as IC310 were believed to originate in the particle jets produced by the black holes. These jets are detected in many galaxies, and they expand for hundreds of thousands light-years. When a jet points directly towards the Earth, a relativistic effect, called “apparent superluminous motion”, is produced, due to the similar speeds at which the emitter (jet particles) and the emission (the gamma rays) travel toward us. As a result, the measured intensity of the gamma-ray emission is higher, and its variability faster. However, this explication does not apply to the case of IC310, as its jets do not point at us. The gamma rays must be created practically on the black hole itself. MAGIC is the present of a young yet fruitful field of science known as Ground-based Gamma-ray Astronomy. Its first steps at Roque de los Muchachos Observatory of the Instituto de Astrofísica de Canarias trace back to the 1980s, with the HEGRA telescopes. The imminent future of the field is the Cherenkov Telescope Array (CTA), to be formed of about 100 telescopes at two observatories (in the Northern and Southern Hemispheres). The Spanish groups of the MAGIC Collaboration have presented a candidacy to build the CTA-North observatory at Roque de los Muchachos or at Teide. This is the best opportunity for Spain to host one of the major global scientific installations that will mark the progress of Astronomy in the years to come. MAGIC consists of two, 17-m diameter reflective telescopes, built and operated by an international collaboration of 160 scientists from Spain, Germany, Italy, Poland, Switzerland, Finland, Bulgaria, Croatia, Japan and India. MAGIC is celebrating its tenth anniversary with its fifth scientific publication in Science Magazine. Major contributions of the Spanish groups to the construction of MAGIC include the original camera of one of the telescopes, most of the electronics and the data center. The success of the experiment has been possible thanks to the quality of the sky at La Palma. The Spanish institutes participating in the experiment are: Instituto de Física de Altas Energías (IFAE, Barcelona), Universidad Autónoma de Barcelona, Universidad de Barcelona, Instituto de Ciencias del Espacio (CSIC, Barcelona), Instituto de Astrofísica de Canarias (IAC, La Laguna), Universidad Complutense de Madrid and Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT, Madrid). Further information on MAGIC:
A Black hole gamma-ray lightning was recorded in The Canary Islands
The scientists explain this phenomenon by a mechanism similar to that producing lightning in a stor
Un superbólido cruza el cielo de Catalunya [NOT TRANSLATED]
INTEGRAL catches dead star exploding in a blaze of glory
27 August 2014 by ESA Astronomers using ESA's INTEGRAL gamma-ray observatory have demonstrated beyond doubt that dead stars known as white dwarfs can reignite and explode as supernovae The finding came after the unique signature of gamma rays from the radioactive elements created in one of these explosions was captured for the first time. The explosions in question are known as Type Ia supernovae, long suspected to be the result of a white dwarf star blowing up because of a disruptive interaction with a companion star. However, astronomers have lacked definitive evidence that a white dwarf was involved until now. The 'smoking gun' in this case was evidence for radioactive nuclei being created by fusion during the thermonuclear explosion of the white dwarf star. "INTEGRAL has all the capabilities to detect the signature of this fusion, but we had to wait for more than ten years for a once-in-a-lifetime opportunity to catch a nearby supernova," says Eugene Churazov, from the Space Research Institute (IKI) in Moscow, Russia and the Max Planck Institute for Astrophysics,in Garching, Germany. Although Type Ia supernovae are expected to occur frequently across the Universe they are rare occurrences in any one galaxy, with typical rates of one every few hundred years. INTEGRAL's chance came on 21 January 2014, when students at the University College London's teaching observatory at Mill Hill, UK detected a type Ia supernova, later named SN2014J, in the nearby galaxy M82. According to the theory of such explosions, the carbon and oxygen found in a white dwarf should be fused into radioactive nickel during the explosion. This nickel should then quickly decay into radioactive cobalt, which would itself subsequently decay, on a somewhat longer timescale, into stable iron. Because of its proximity – at a distance of about 11.5 million light-years from Earth, SN2014J is the closest of its type to be detected in decades – INTEGRAL stood a good chance of seeing the gamma rays produced by the decay. Within one week of the initial discovery, an observing plan to use INTEGRAL had been drawn-up and approved. Using INTEGRAL to study the aftermath of the supernova explosion, scientists looked for the signature of cobalt decay – and they found it, in exactly the quantities that the models predicted. "The consistency of the spectra, obtained by INTEGRAL 50 days after the explosion, with that expected from cobalt decay in the expanding debris of the white dwarf was excellent," says Churazov, who is lead author of a paper describing this study and reported in the journal Nature. With that confirmation in hand, other astronomers could begin to look into the details of the process. In particular, how the white dwarf is detonated in the first place. White dwarfs are inert stars that contain up to 1.4 times the mass of the Sun squeezed into a volume about the same size as the Earth. Being inert, they can't simply blow themselves up. Instead, astronomers believe that they leech matter from a companion star, which builds up on the surface until a critical total mass is reached. At that point, the pressure in the heart of the white dwarf triggers a catastrophic thermonuclear detonation. Early INTEGRAL observations of SN2014J tell a somewhat different story, and have been the focus of a separate study, reported online in Science Express by Roland Diehl from the Max Planck Institute for Extraterrestrial Physics, Germany, and colleagues. Diehl and his colleagues detected gamma rays from the decay of radioactive nickel just 15 days after the explosion. This was unexpected, because during the early phase of a Type Ia supernova, the explosion debris is thought to be so dense that the gamma rays from the nickel decay should be trapped inside. "We were puzzled by this surprising signal, and some from the group even thought it must be wrong," says Diehl. "We had long and ultimately very fruitful discussions about what might explain these data." A careful examination of the theory showed that the signal would have been hidden only if the explosion had begun in the heart of the white dwarf. Instead, Diehl and colleagues think that what they are seeing is evidence for a belt of gas from the companion star that must have built up around the equator of the white dwarf. This outer layer detonated, forming the observed nickel and then triggering the internal explosion that became the supernova. "Regardless of the fine details of how these supernovae are triggered, INTEGRAL has proved beyond doubt that a white dwarf is involved in these stellar cataclysms," says Erik Kuulkers, ESA's INTEGRAL Project Scientist. "This clearly demonstrates that even after almost twelve years in operation, INTEGRAL is still playing a crucial role in unraveling some of the mysteries of the high-energy Universe." Notes for editors "56Co gamma-ray emission lines from the type Ia supernova SN2014J" by E. Churazov et al., is published in the 28 August 2014 issue of Nature; DOI: 10.1038/nature13672 "Early 56Ni decay ? rays from SN2014J suggest an unusual explosion" by R. Diehl et al., appeared online in Science Express on 31 July 2014; DOI: 10.1126/science.1254738 Some of the observations of SN2014J were obtained as part of an INTEGRAL Target of Opportunity programme led by Principal Investigator Jordi Isern (ICE-CSIC/IEEC, Spain). The INTEGRAL Project Scientist, Erik Kuulkers, made additional observing time available, on request of the INTEGRAL supernova community, to maximise the scientific return. This was supplemented by a contribution from the Russian guaranteed time on the recommendation of the Russian INTEGRAL Advisory Committee. Type Ia supernovae are particularly important because they are used to gauge distances across much of the visible Universe. In the 1990s, their study led to the discovery of the cosmic acceleration that is now thought to be powered by a mysterious form of energy called 'dark energy'. The Nobel Prize for Physics ESA Science & Technology:INTEGRAL catches dead star ex... 2 in 2011 was awarded to Saul Perlmutter, Adam Riess, and Brian Schmidt for their role in the discovery of dark energy. The International Gamma-ray Astrophysics Laboratory (INTEGRAL) was launched on 17 October 2002. It is an ESA project with the instruments and a science data centre funded by ESA Member States (especially the Principal Investigator countries: Denmark, France, Germany, Italy, Spain, Switzerland), and with the participation of Russia and the USA. The mission is dedicated to the fine spectroscopy (E/?E = 500) and fine imaging (angular resolution: 12 arcmin FWHM) of celestial gamma-ray sources in the energy range 15 keV to 10 MeV with concurrent source monitoring in the X-ray (4-35 keV) and optical (V-band, 550 nm) wavelengths. Contacts Markus Bauer ESA Science and Robotic Exploration Communication Officer Email: markus.bauer Phone: +31-71-565-6799 Mobile: +31-61-594-3-954 Eugene Churazov Space Research Institute (IKI), Moscow, Russia Email: churazov Phone: +7-495-3333377 and Max Planck Institute for Astrophysics, Germany Email: churazov Phone: +49-89-30000-2219 Roland Diehl Max Planck Institute for Extraterrestrial Physics, Germany Email: rod Phone: +49-89-30000-3850 Erik Kuulkers INTEGRAL Project Scientist Directorate of Science and Robotic Exploration European Space Agency Email: Erik.Kuulkers Phone: +34-91-8131-358 Images And Videos Supernova explosion (artist's impression) ( Supernova SN2014J in nearby galaxy M82 ( Related Publications Churazov et al. [2014] ( Diehl et al. [2014] (
Two bright fireballs that overflew the Atlantic Ocean in 2009 and 2010 came from a potencially hazardous asteroid
Ardón: un meteorito español caído en 1931 [NOT TRANSLATED]
Ardón ha sido reconocido como caída meteorítica por la Meteoritical Society, gracias a la investigación realizada Los análisis realizados por el CSIC indican que se trata de una condrita ordinaria Un equipo internacional liderado por el Consejo Superior de Investigaciones Científicas (CSIC) ha caracterizado un nuevo meteorito caído en España, recuperado tras permanecer oculto durante 83 años. Se trata de una condrita ordinaria del grupo L6 procedente de un asteroide desconocido que ha recibido el nombre de Ardón, municipio leonés donde cayó, y su caracterización por el CSIC ha permitido que sea reconocida como nueva caída por la Meteoritical Society. El 9 de julio de 1931, a las 9.30 horas, una enorme bola de fuego sobrevoló la provincia de León y generó una serie de estallidos audibles desde la capital y otros municipios próximos, entre ellos Boñar y Cistierna, como recogieron los medios de comunicación de la época. Rosa González Pérez, entonces una niña de 11 años, se encontraba haciendo un recado en el centro del municipio de Ardón cuando escuchó un estruendo que surgió de una estela de polvo. Justo delante de ella vio caer del cielo una pequeña roca humeante y al recogerla notó que todavía estaba caliente. Por desconocimiento, no comentó nada sobre su hallazgo y la guardó en una cajita, preservándola en muy buenas condiciones durante más de 80 años. Fue un sobrino, J. Antonio González, quien años más tarde pensó que esa pequeña roca negruzca de 5,5 gramos podría ser importante. En 2013, los propietarios se pusieron en contacto con el investigador del CSIC Josep Maria Trigo, del Grupo de Meteoritos del Instituto de Ciencias del Espacio del CSIC y también miembro del Instituto de Estudios Espaciales de Cataluña, quien rápidamente supo que la roca era un meteorito. Trigo comenzó la tarea de caracterizarlo junto a Jordi Llorca, de la Universidad Politécnica de Cataluña, y se dieron cuenta de que se trataba de un meteorito primitivo: una condrita ordinaria procedente de un asteroide desconocido. Los científicos comenzaron entonces los análisis químicos y mineralógicos requeridos para clasificar y dar nombre al meteorito, trámites necesarios para que sea catalogado por la Meteoritical Society, organismo profesional a nivel internacional encargado de esta labor. Una vez finalizado el proceso, sus propietarios han donado una sección del ejemplar al Museo Nacional de Ciencias Naturales del CSIC, en Madrid, para que sea expuesto al público junto al resto de la colección de meteoritos del museo. “La familia ha accedido a donar una lámina de ese ejemplar. Además, se hará una réplica que podrá verse junto al resto de meteoritos españoles en la sala habilitada a tal fin en el Museo Nacional de Ciencias Naturales. Agradecemos la donación del fragmento dado su valor científico y esperamos que esta acción sirva para incentivar otras donaciones” señala Santiago Merino, director del museo. Meteoritos ocultos La caída de Ardón podría no ser un caso aislado ya que el número de caídas de meteoritos en España es muy inferior al que sugieren las estadísticas. “Los estudios de grandes bólidos que generan meteoritos indican que, por término medio, debe acontecer anualmente en España la caída de un meteorito con una masa superior a un kilogramo”, señala Trigo. “Sin embargo, nuestra recuperación del meteorito Villalbeto de la Peña en 2004 pocas semanas después de su caída ocurrió más de 56 años después de la caída de Reliegos (1947). En la última década, gracias a nuestros esfuerzos por estudiar estos fenómenos en el seno de la Red de Investigación sobre Bólidos y Meteoritos, participamos también en la recuperación de otro en Puerto Lápice en 2007. Ahora es una satisfacción enorme para nuestra red poner al municipio leonés de Adrón en un lugar en la historia de la meteorítica”, continúa. Los investigadores sospechan que algunos meteoritos podrían permanecer ocultos como secretos familiares o ser vendidos para acabar en colecciones privadas de las que se pierde toda pista. En ese sentido, la Ley del Patrimonio Natural y de la Biodiversidad de 2007 reconoce que los meteoritos españoles son patrimonio geológico y, por tanto, deben ser preservados y permanecer en el país. El interés astroquímico de Ardón Las condritas ordinarias son el tipo de meteoritos más común, con algo más de un 73% de todas las caídas de meteoritos conocidas hasta la fecha. De hecho, del mismo grupo L de la condrita Ardón se conocen otras 406 catalogadas en el Boletín Meteorítico de la Meteoritical Society. La más antigua conocida es la condrita Nogata, caída en Japón en el año 861. Sin embargo, la inmensa mayoría de las que se preservan cayeron en los últimos 300 años, es el caso del meteorito Villalbeto de la Peña, que cayó el 4 de enero de 2004 en la población palentina del mismo nombre. Se ha propuesto que las condritas ordinarias del grupo L proceden de una familia de asteroides producida por la desintegración del asteroide 1.272 Gefion, que explicaría que sean tan comunes entre las caídas actuales. De hecho, la datación isotópica de sus edades de rayos cósmicos (el tiempo que llevan surcando el Sistema Solar como pequeñas rocas) indica que su cuerpo progenitor debió sufrir varias colisiones de envergadura que produjeron gran cantidad de estos escombros en los últimos 40 millones de años. Hoy en día, esos fragmentos alcanzan la Tierra tras ser lanzados desde el cinturón principal de asteroides mediante mecanismos dinámicos que se conocen como resonancias y que también impulsan desde allí a los llamados asteroides próximos a la Tierra. El estudio del meteorito Ardón está permitiendo conocer los procesos que ocurrieron durante la formación del Sistema Solar pero también durante el procesado térmico que sufrió su asteroide progenitor. “Ardón es un meteorito muy interesante pues proviene de un asteroide primitivo pero que, dadas sus mayores dimensiones, sus minerales fueron alterados térmicamente por metamorfismo. También presenta evidencias claras de los procesos de choque acaecidos en ese asteroide mientras estuvo en órbita alrededor del Sol”, explica Trigo. “En la composición mayoritaria del meteorito encontramos silicatos, sulfuros y metales, componentes cuyas características isotópicas indican que participaron en la formación de nuestro planeta. Además, Ardón ha preservado en su textura pequeñas esférulas vítreas denominadas cóndrulos y granos metálicos que giraban alrededor del Sol hace unos 4.565 millones de años: los primeros componentes sólidos del Sistema Solar formados mucho antes que nuestra propia Tierra”, añade el investigador del CSIC. Josep M. Trigo-Rodriguez, Jordi Llorca, M. Weyrauch and A. Bischoff. Ardón: L6 ordinary chondrite. Meteoritical Bulletin 103. Press release [NOT TRANSLATED]
Identified a spanish meteorite fallen in 1931, Ardón
The rock, which is an ordinary chondrite, has been recognized as a meteorite fall by the Meteoritical Society
Spanish researchers discover the first black hole orbiting a ‘spinning’ star
The discovery of this striking pair is published today in Nature Spanish scientists have discovered the first binary system ever known to consist of a black hole and a ‘spinning’ star – or more accurately, a Be-type star. Although predicted by theory, none had previously been found. The observations that led to the discovery were performed with the Liverpool and Mercator telescopes at the Observatorio del Roque de los Muchachos (Canary Islands, Spain). The discovery is published today in Nature. Be-type stars are quite common across the Universe. In our Galaxy alone more than 80 of them are known in binary systems together with neutron stars. ‘Their distinctive property is their strong centrifugal force: they rotate very fast, close to their break-up speed. It's like they were cosmic spinning tops,’says Jorge Casares of the Instituto de Astrofísica de Canarias (IAC) and La Laguna University (ULL). Casares is the lead author and an expert in stellar-mass black holes (he presented the first solid proof of their existence back in 1992). The newly discovered black hole orbits the Be star known as MWC 656, located in the constellation Lacerta (the Lizard) - 8,500 light years from Earth. The Be star rotates so fast that its surface speed exceeds 1 million kilometres per hour. ‘We started studying this star back in 2010, when space telescopes detected transient gamma-ray emission coming from its direction,’ explains Marc Ribó, of the Institut de Ciències del Cosmos of Barcelona University (ICC/IEEC-UB). ‘No more gamma-ray emission has subsequently been detected, but we found that the star was part of a binary system,’ he adds. A detailed analysis of its spectrum allowed scientists to infer the characteristics of its companion. ‘It turned out to be an object with a mass between 3.8 and 6.9 solar masses. An object like that, invisible to telescopes and with such large mass, can only be a black hole, because no neutron star with more than three solar masses can exist,’ states Ignasi Ribas, of CSIC in the Instituto de Ciencias del Espacio (IEEC-CSIC). The black hole orbits the (more massive) Be star and is fed by matter ejected from the latter. ‘The high rotation speed of the Be star causes matter to be ejected into an equatorial disc. This matter is attracted by the black hole and falls on to it, forming another disc - called an “accretion disc”’. By studying the emission from the accretion disc we could analyse the motion of the black hole and measure its mass,’ comments Ignacio Negueruela, a lecturer at the University of Alicante (UA). Scientists believe this object to be a nearby member of a hidden population of Be stars paired with black holes. ‘We think these systems are much more common than previously thought, but they’re difficult to detect because their black holes are fed from gas ejected by the Be stars without producing much radiation, in a “silent” way, so to speak. However, we hope to detect other similar binary systems in the Milky Way and other nearby galaxies by using bigger telescopes, such as the Gran Telescopio Canarias,’ concludes Casares. Also participating in the study with Jorge Casares, Ignacio Negueruela, Marc Ribó and Ignasi Ribas are Josep M. Paredes , of Institut de Ciències del Cosmos of Barcelona University (ICC/IECC-UB) and Artemio Herrero and Sergio Simón, both from the IAC and ULL. Black holes, an ongoing challenge The detection of black holes has been a challenge since their existence was first surmised by John Michell and Pierre Laplace in the 18th century. Given that they are invisible - their enormous gravitational force prevents light from escaping – telescopes cannot detect them. However, black holes can occasionally trigger high energy radiation from the environment surrounding them and can thus be traced by X-ray satellites. This is the case with active black holes, fed by matter transferred from a nearby star. If violent X-ray emission is detected from a place where nothing but a normal star is seen, a black hole might be hiding there. Using this method, researchers have discovered 55 potential black holes over the last 50 years. Seventeen of them have what astronomers call a ‘dynamic confirmation’: the feeding star has been localised, allowing for the mass of its invisible companion to be measured. If it is above three solar masses, then it is considered to be a black hole. The biggest problem is put forth by ‘dormant’ black holes, such as the one found by the Spanish researchers: ‘Their X-ray emission is almost absent, and so it is very unlikely that our attention would be drawn to them,’ Casares explains. Researchers believe there are thousands of black hole binary systems across the Milky Way, some of them also with Be-type stellar companions. J.Casares, I.Negueruela, M.Ribó, I.Ribas, J.M.Paredes, A.Herrero, S.Simón-Díaz. A Be-type star with a black-hole companion. Nature. DOI: 10.1038/nature12916 Contacts: Jorge Casares: ( 922 605258 Ignacio Negueruela: ( 965 903400-ext 1152 Marc Ribó: ( 93 4034986 Ignasi Ribas: ( 93 5814371 Josep M. Paredes: ( 93 4021130 Artemio Herrero: ( 922 605317 Sergio Simón: ( 922 605391
Researchers discover the first black hole orbiting a ‘spinning’ star
The discovery of this striking pair is published today in Nature
Gaia takes off successfully towards the Milky Way
Today at 10:12:19 (GMT) the satellite Gaia has been successfully launched. After overcoming the first stages of the launch -separation of driving rockets, separation of second and third stages, liting of Fregat and Gaia separation-, Gaia has also passed the most critical stage, the unfurling of the parasol. Gaia is now outside the orbit of the Earth and heads to its point of observation, L2, 1.5 million kilometers away, where it will arrive within a month.
Las explosiones más brillantes del Universo parecen estar alimentadas por los campos magnéticos de las estrellas de neutrones [NOT TRANSLATED]
Un equipo científico europeo, del que forman parte dos astrónomas españolas, Nancy Elias-Rosa y Antonia Morales-Garoffolo, del Instituto de Ciencias del Espacio (CSIC/IEEC) publica hoy un trabajo en Nature que da nuevas claves para entender las supernovas más brillantes descubiertas hasta el momento en el Universo: las supernovas superluminosas (SLSN). El artículo propone que estas explosiones de supernova tan brillantes podrían estar provocadas por estrellas de neutrones que giran cientos de veces por segundo creando campos magnéticos enormes. Las estrellas masivas finalizan su vida como explosiones estelares espectaculares llamadas supernovas, llenando el Universo de todos los elementos químicos que vemos a nuestro alrededor. Son miles de millones de veces más brillantes que el Sol, de hecho son tan brillantes que hay una gran comunidad de astrónomos que inspeccionan el cielo regularmente en busca de nuevas supernovas en galaxias cercanas. Se sabe desde hace décadas que el calor y la luz de estos eventos tienen su origen en las ondas explosivas y material radioactivo que generan las estrellas masivas cuando, al final de su vida, se desploman sobre sí mismas para dar lugar a una estrella de neutrones o un agujero negro. Sin embargo, recientemente, se ha descubierto la existencia de supernovas demasiado luminosas (las SLSN) para ser interpretadas de esta manera. Estas supernovas son cientos de veces más brillantes que las supernovas típicas y el origen de sus propiedades extremas es aún un misterio. Los descubrimientos de estas particulares explosiones estelares han sido posibles gracias al nacimiento en los últimos años de varios programas científicos que cartografían constantemente el cielo en busca de nuevos tipos de objetos transitorios. Gracias a uno de estos programas, Pan-STARRS (‘Panoramic Survey Telescope and Rapid Response System’), se encontraron dos supernovas que resultaron ser de las más brillantes jamás descubiertas. El equipo europeo mencionado anteriormente observó su evolución durante más de un año mientras se apagaban lentamente, y para ello utilizaron algunos de los telescopios más grandes del mundo. En particular, el Instituto de Ciencias del Espacio (CSIC/IEEC) participó con observaciones muy relevantes obtenidas con el Gran Telescopio de Canarias, un telescopio con un espejo de 10 metros de diámetro, ubicado en el Observatorio del Roque de los Muchachos en la isla de La Palma. Sólo un telescopio de estas dimensiones podría obtener datos de buena calidad en las últimas fases de una supernova, cuando esta está desapareciendo. Algunos físicos teóricos habían predicho que estos tipos extremos de explosión provenían de las estrellas más masivas del Universo cuando, al final de sus vidas, colapsaban sobre sí mismas estallando de manera parecida a una bomba gigante, la cual podría alcanzar un tamaño 100 veces mayor que el Sol, o 30 millones de veces el de la Tierra. Sin embargo, los datos recopilados en este estudio muestran que estos modelos no concuerdan con lo que vemos. Las SLSN que se han investigado en este artículo, se explican mejor si su brillo es alimentado por el campo magnético de una estrella de neutrones que gira rápidamente sobre sí misma y no por las estrellas extremadamente supermasivas predichas teóricamente. Los autores del artículo explican: “Sabemos que cuando una estrella masiva alcanza el final de su vida, sus capas externas son eyectadas violentamente en forma de supernova mientras que su núcleo colapsa para formar una estrella de neutrones- pesando tanto como el Sol pero con un radio de algo más de una decena de kilómetros. Pensamos que en un número pequeño de casos, la estrella de neutrones tiene un campo magnético muy potente y gira muy rápidamente sobre su eje, del orden de 300 veces por segundo. A medida que se ralentiza podría transferir parte de la energía asociada al giro a la supernova a través de su campo magnético, haciéndola mucho más brillante de lo normal. Los datos que hemos analizado en este estudio parecen concordar con esta predicción de manera casi exacta.” Por otro lado hay que tener en cuenta que estas son supernovas muy especiales, porque son tan brillantes que podemos considerarlas como mensajeros del Universo lejano. La luz viaja a través del espacio a una velocidad constante, a medida que miramos más lejos, vemos instantáneas del pasado cada vez más lejano. Si pudiéramos entender los procesos que dan lugar a estas brillantes explosiones, podríamos sondear cómo era el Universo poco después de su nacimiento. El objetivo de esta colaboración es encontrar estas supernovas en el universo temprano, y ver cómo se producen los primeros elementos químicos en el Universo. [NOT TRANSLATED]
The Dark Energy Survey project begins its five-year mission to map the southern sky in great detail
- La Cámara de Energía Oscura DECam es el instrumento más poderoso construido para un cartografiado de esta índole. Con cada imagen instantánea, será capaz de ver la luz de más de 100.000 galaxias a hasta 8 mil millones de años luz de distancia.
La variabilidad de larga duración en la emisión gamma conecta fenómenos estelares [NOT TRANSLATED]
Article in Spanish
Descubren una nueva clase de estrellas pulsantes en un sistema binario eclipsante [NOT TRANSLATED]
- El sistema descubierto es un sistema binario compuesto por el núcleo desnudo de una gigante roja y una estrella similar al Sol.
Generalitat de CatalunyaUniversitat de BarcelonaUniversitat Autònoma de BarcelonaUniversitat Politècnica de CatalunyaConsejo Superior de Investigaciones CientíficasCentres de Recerca de Catalunya