Press Release<\/p>\n
12 January 2026<\/p>\n
Gas and dust flowing from stars can, under the right conditions, clash with a star\u2019s surroundings and create a shock wave. Now, astronomers using the European Southern Observatory\u2019s Very Large Telescope (ESO\u2019s VLT) have imaged a beautiful shock wave around a dead star \u2014 a discovery that has left them puzzled. According to all known mechanisms, the small, dead star RXJ0528+2838 should not have such structure around it. This discovery, as enigmatic as it\u2019s stunning, challenges our understanding of how dead stars interact with their surroundings.<\/p>\n
\u201cWe found something never seen before and,\u00a0more importantly, entirely unexpected,\u201d\u00a0says Simone Scaringi, associate professor at Durham University, UK and co-lead author\u00a0of\u00a0the study published today in\u00a0Nature Astronomy.\u00a0\u201cOur observations reveal a powerful outflow that, according to our current understanding, shouldn\u2019t be there,\u201d\u00a0says Krystian\u00a0I\u0142kiewicz, a postdoctoral researcher at the Nicolaus Copernicus Astronomical\u00a0Center\u00a0in Warsaw,\u00a0Poland\u00a0and study co-lead.\u00a0\u2018Outflow\u2019\u00a0is the term used by astronomers to describe the material that is ejected from celestial objects.\u00a0<\/p>\n
The star RXJ0528+2838 is\u00a0located\u00a0730 light-years away and, like the Sun and other stars, it rotates around our galaxy\u2019s centre. As it moves, it interacts with the gas that permeates the space between stars, creating a type of shock wave called a bow shock,\u00a0\u201ca curved arc of material, similar to the wave that builds up in front of a ship,\u201d\u00a0explains Noel Castro Segura, research fellow at the University of Warwick in the UK and collaborator in this study. These bow shocks are usually created by material outflowing from the central star, but in the case of RXJ0528+2838, none of the known mechanisms can fully explain the observations.\u00a0<\/p>\n
RXJ0528+2838 is a white dwarf \u2014 the left-over core of a dying low-mass star \u2014 and has a Sun-like companion orbiting it. In such binary systems, the material from the companion star is transferred to the white dwarf, often forming a disc around it. While the disc fuels the dead star, some of the material also gets ejected into space, creating powerful outflows. But RXJ0528+2838\u00a0shows\u00a0no signs of a disc, making the origin of the outflow and resulting nebula around the star a mystery.\u00a0<\/p>\n
\u201cThe surprise that a\u00a0supposedly quiet, discless system could drive such a spectacular nebula was one of those rare \u2018wow\u2019 moments,\u201d\u00a0says Scaringi.\u00a0<\/p>\n
The team first spotted a strange nebulosity around RXJ0528+2838 on images from the Isaac Newton Telescope in Spain. Noticing its unusual shape, they\u00a0observed\u00a0it in more detail with the MUSE instrument on\u00a0ESO\u2019s VLT<\/a>.\u00a0\u201cObservations with the ESO MUSE instrument allowed us to map the bow shock in detail and analyse its composition. This was crucial to confirm that the structure really originates from the binary system and not from an unrelated nebula or interstellar cloud,\u201d\u00a0I\u0142kiewicz\u00a0explains.\u00a0\u00a0<\/p>\n The shape and size of the bow shock\u00a0imply\u00a0that the white dwarf has been expelling a powerful outflow for at least 1000 years. Scientists\u00a0don\u2019t\u00a0know exactly how a dead star without a disc can power such a long-lasting outflow \u2014 but they\u00a0do\u00a0have a guess.\u00a0<\/p>\n This white dwarf is known to host a strong magnetic field, which has been confirmed by the\u00a0MUSE<\/a>\u00a0data. This field channels the material stolen from the companion star directly onto the white dwarf, without forming a disc around it. \u201cOur finding shows that even without a disc,\u00a0these systems can drive powerful outflows, revealing a mechanism we do not yet understand. This discovery challenges the standard picture of how matter moves and interacts in these extreme binary systems,\u201d\u00a0I\u0142kiewicz explains.\u00a0\u00a0<\/p>\n The results hint at a hidden energy source,\u00a0likely the\u00a0strong magnetic field, but this\u00a0\u2018mystery engine\u2019,\u00a0as Scaringi puts it, still needs to be investigated. The data show\u00a0that the current magnetic field is only strong enough to power a bow shock lasting for a few hundred years, so it only partly explains what the astronomers are seeing.\u00a0<\/p>\n To better understand the nature of such discless outflows, many more binary systems need to be studied. ESO\u2019s upcoming Extremely Large Telescope (ELT<\/a>) will help astronomers\u00a0\u201cto map more of these systems as well as fainter ones and detect similar systems in detail, ultimately helping in understanding the mysterious energy source that remains unexplained,\u201d\u00a0as\u00a0Scaringi foresees.\u00a0<\/p>\n More information<\/p>\n This research was presented in a paper titled \u201cA persistent bow shock in a diskless magnetised accreting white dwarf\u201d to appear in\u00a0Nature Astronomy\u00a0(doi: 10.1038\/s41550-025-02748-8).\u00a0<\/p>\n The team is composed of Krystian\u00a0I\u0142kiewicz\u00a0(Nicolaus Copernicus Astronomical\u00a0Center, Polish Academy of Sciences, Warsaw, Poland and Centre for Extragalactic Astronomy, Department of Physics, Durham University, Durham, UK\u00a0[CEA Durham]), Simone Scaringi (CEA Durham\u00a0and INAF-Osservatorio\u00a0Astronomico\u00a0di Capodimonte, Naples, Italy\u00a0[Capodimonte]), Domitilla de Martino (Capodimonte), Christian Knigge (Department of Physics & Astronomy, University of Southampton, Southampton, UK), Sara E. Motta (Istituto Nazionale di\u00a0Astrofisica,\u00a0Osservatorio\u00a0Astronomico\u00a0di Brera,\u00a0Merate, Italy and University of Oxford, Department of Physics, Oxford, UK\u00a0[Oxford]), Nanda Rea (Institute of Space Sciences (ICE, CSIC), Barcelona, Spain and\u00a0Institut\u00a0d\u2019Estudis\u00a0Espacials\u00a0de Catalunya (IEEC),\u00a0Castelldefels, Spain), David Buckley (South African Astronomical Observatory, South Africa\u00a0[SAAO]\u00a0and Department of Astronomy & IDIA, University of Cape Town,\u00a0Rondebosh, South Africa\u00a0[Cape Town]\u00a0and Department of Physics, University of the Free State, Bloemfontein, South Africa), Noel Castro Segura (Department of Physics, University of Warwick, Coventry, UK), Paul J. Groot (SAAO\u00a0and\u00a0Cape Town\u00a0and Department of Astrophysics\/IMAPP, Radboud University, Nijmegen, The Netherlands), Anna F. McLeod (CEA Durham\u00a0and Institute for Computational Cosmology, Department of Physics, University of Durham, Durham UK), Luke T. Parker (Oxford), and Martina\u00a0Veresvarska\u00a0(CEA Durham).\u00a0<\/p>\n The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design,\u00a0build\u00a0and\u00a0operate\u00a0world-class observatories on the ground \u2014 which astronomers use to tackle exciting questions and spread the fascination of astronomy \u2014 and promote\u00a0international\u00a0collaboration\u00a0for\u00a0astronomy. Established as an intergovernmental\u00a0organisation\u00a0in 1962, today ESO is supported by 16 Member States (Austria, Belgium,\u00a0Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO\u2019s headquarters and its visitor\u00a0centre\u00a0and planetarium, the ESO Supernova, are\u00a0located\u00a0close to Munich in Germany, while the Chilean Atacama Desert, a\u00a0marvellous\u00a0place with unique conditions to\u00a0observe\u00a0the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and\u00a0Chajnantor.\u00a0At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA.\u00a0Also\u00a0at Paranal,\u00a0ESO will host and\u00a0operate\u00a0the\u00a0south array of the\u00a0Cherenkov Telescope Array\u00a0Observatory, the world\u2019s largest and most sensitive gamma-ray observatory. Together with\u00a0international\u00a0partners, ESO operates ALMA on\u00a0Chajnantor,\u00a0a facility that\u00a0observes\u00a0the skies in the\u00a0millimetre\u00a0and\u00a0submillimetre\u00a0range. At Cerro\u00a0Armazones, near Paranal, we are building \u201cthe world\u2019s biggest eye on the sky\u201d \u2014 ESO\u2019s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.\u00a0<\/p>\n Links \nKrystian I\u0142kiewicz \nSimone Scaringi \nNoel Castro Segura \nB\u00e1rbara Ferreira
\nContacts<\/p>\n
Nicolaus Copernicus Astronomical Center
Warsaw, Poland
Tel: +48 223296134
Email: ilkiewicz@camk.edu.pl<\/a><\/p>\n
Centre for Extragalactic Astronomy, Department of Physics, Durham University
Durham, UK
Cell: +44 7737 980235
Email: simone.scaringi@durham.ac.uk<\/a><\/p>\n
Department of Physics, University of Warwick
Coventry, UK
Tel: +44 7859 761377
Email: noel.castro-segura@warwick.ac.uk<\/a><\/p>\n
ESO Media Manager
Garching bei M\u00fcnchen, Germany
Tel: +49 89 3200 6670
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Email: press@eso.org<\/a><\/p>\n