[et_pb_section fb_built=\u00bb1″ fullwidth=\u00bbon\u00bb theme_builder_area=\u00bbpost_content\u00bb _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb height=\u00bb114px\u00bb background_color=\u00bb\u00bb hover_enabled=\u00bb0″ sticky_enabled=\u00bb0″ title_text=\u00bb\u00bb background_image=\u00bb\/wp-content\/uploads\/2022\/04\/slider-corpo2.jpg\u00bb][\/et_pb_section][et_pb_section fb_built=\u00bb1″ theme_builder_area=\u00bbpost_content\u00bb _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb custom_padding=\u00bb||0px||false|false\u00bb custom_margin=\u00bb||0px||false|false\u00bb hover_enabled=\u00bb0″ sticky_enabled=\u00bb0″][et_pb_row _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb theme_builder_area=\u00bbpost_content\u00bb][et_pb_column _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb type=\u00bb4_4″ theme_builder_area=\u00bbpost_content\u00bb][et_pb_text _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb theme_builder_area=\u00bbpost_content\u00bb _dynamic_attributes=\u00bbcontent\u00bb hover_enabled=\u00bb0″ sticky_enabled=\u00bb0″ custom_margin=\u00bb0px||0px||false|false\u00bb custom_padding=\u00bb0px||0px||false|false\u00bb]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF90aXRsZSIsInNldHRpbmdzIjp7ImJlZm9yZSI6IjxoMSBjbGFzcz1cImVudHJ5X3RpdGxlXCI+IiwiYWZ0ZXIiOiI8L2gxPiJ9fQ==@[\/et_pb_text][et_pb_text _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb theme_builder_area=\u00bbpost_content\u00bb _dynamic_attributes=\u00bbcontent\u00bb custom_padding=\u00bb0px||0px||false|false\u00bb custom_margin=\u00bb0px||0px||false|false\u00bb hover_enabled=\u00bb0″ sticky_enabled=\u00bb0″]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImN1c3RvbSIsImN1c3RvbV9kYXRlX2Zvcm1hdCI6IlktbS1kIEg6aTpzIn19@[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=\u00bb1″ _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb custom_margin=\u00bb0px||||false|false\u00bb custom_padding=\u00bb0px||||false|false\u00bb top_divider_color=\u00bbRGBA(255,255,255,0)\u00bb top_divider_height=\u00bb0px\u00bb hover_enabled=\u00bb0″ global_colors_info=\u00bb{}\u00bb sticky_enabled=\u00bb0″][et_pb_row column_structure=\u00bb4_4″ _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb global_colors_info=\u00bb{}\u00bb][et_pb_column type=\u00bb4_4″ _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb global_colors_info=\u00bb{}\u00bb][et_pb_text _builder_version=\u00bb4.14.8″ _module_preset=\u00bbdefault\u00bb global_colors_info=\u00bb{}\u00bb]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 \u2018spinning\u2019 star \u2013 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. \u2018Their 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,\u2019says Jorge Casares of the Instituto de Astrof\u00edsica 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. \u2018We started studying this star back in 2010, when space telescopes detected transient gamma-ray emission coming from its direction,\u2019 explains Marc Rib\u00f3, of the Institut de Ci\u00e8ncies del Cosmos of Barcelona University (ICC\/IEEC-UB). \u2018No more gamma-ray emission has subsequently been detected, but we found that the star was part of a binary system,\u2019 he adds. A detailed analysis of its spectrum allowed scientists to infer the characteristics of its companion. \u2018It 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,\u2019 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. \u2018The 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 \u201caccretion disc\u201d\u2019. By studying the emission from the accretion disc we could analyse the motion of the black hole and measure its mass,\u2019 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. \u2018We think these systems are much more common than previously thought, but they\u2019re difficult to detect because their black holes are fed from gas ejected by the Be stars without producing much radiation, in a \u201csilent\u201d 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,\u2019 concludes Casares. Also participating in the study with Jorge Casares, Ignacio Negueruela, Marc Rib\u00f3 and Ignasi Ribas are Josep M. Paredes , of Institut de Ci\u00e8ncies del Cosmos of Barcelona University (ICC\/IECC-UB) and Artemio Herrero and Sergio Sim\u00f3n, 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 \u2013 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 \u2018dynamic confirmation\u2019: 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 \u2018dormant\u2019 black holes, such as the one found by the Spanish researchers: \u2018Their X-ray emission is almost absent, and so it is very unlikely that our attention would be drawn to them,\u2019 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.Rib\u00f3, I.Ribas, J.M.Paredes, A.Herrero, S.Sim\u00f3n-D\u00edaz. A Be-type star with a black-hole companion. Nature. DOI: 10.1038\/nature12916 Contacts: Jorge Casares: (jorge.casares@iac.es) 922 605258 Ignacio Negueruela: (ignacio.negueruela@ua.es) 965 903400-ext 1152 Marc Rib\u00f3: (mribo@ub.edu) 93 4034986 Ignasi Ribas: (iribas@ice.cat) 93 5814371 Josep M. Paredes: (jmparedes@ub.edu): 93 4021130 Artemio Herrero: (ahd@iac.es) 922 605317 Sergio Sim\u00f3n: (ssimon@iac.es) 922 605391 [NOT TRANSLATED][\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"
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 \u2018spinning\u2019 star \u2013 or more accurately, a Be-type star. Although predicted by theory, none had previously been found. The observations that led to the discovery were […]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"2880","footnotes":""},"categories":[99,75],"tags":[],"class_list":["post-4247","post","type-post","status-publish","format-standard","hentry","category-ciencia-noticias","category-noticias"],"yoast_head":"\n