Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud?
On 2024 May 27, the Wide-field X-ray Telescope on board the Space Sciences, University of Chinese Academy of Einstein Probe (EP) mission detected enhanced X-ray emission from a new transient source in the Small Magellanic Cloud during its commissioning phase. Prompt follow-up with the EP Follow-up X...
| Published in: | The Astrophysical Journal Letters |
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Language: | English |
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IOP Publishing
2025-01-01
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| Online Access: | https://doi.org/10.3847/2041-8213/ad9580 |
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| author | A. Marino H. N. Yang F. Coti Zelati N. Rea S. Guillot G. K. Jaisawal C. Maitra J.-U. Ness F. Haberl E. Kuulkers W. Yuan H. Feng L. Tao C. Jin H. Sun W. Zhang W. Chen E. P. J. van den Heuvel R. Soria B. Zhang S.-S. Weng L. Ji G. B. Zhang X. Pan Z. Lv C. Zhang Z. X. Ling Y. Chen S. Jia Y. Liu H. Q. Cheng D. Y. Li K. Gendreau M. Ng T. Strohmayer |
| author_facet | A. Marino H. N. Yang F. Coti Zelati N. Rea S. Guillot G. K. Jaisawal C. Maitra J.-U. Ness F. Haberl E. Kuulkers W. Yuan H. Feng L. Tao C. Jin H. Sun W. Zhang W. Chen E. P. J. van den Heuvel R. Soria B. Zhang S.-S. Weng L. Ji G. B. Zhang X. Pan Z. Lv C. Zhang Z. X. Ling Y. Chen S. Jia Y. Liu H. Q. Cheng D. Y. Li K. Gendreau M. Ng T. Strohmayer |
| author_sort | A. Marino |
| collection | DOAJ |
| container_title | The Astrophysical Journal Letters |
| description | On 2024 May 27, the Wide-field X-ray Telescope on board the Space Sciences, University of Chinese Academy of Einstein Probe (EP) mission detected enhanced X-ray emission from a new transient source in the Small Magellanic Cloud during its commissioning phase. Prompt follow-up with the EP Follow-up X-ray Telescope, the Swift X-ray Telescope. and NICER have revealed a very soft, thermally emitting source ( kT ~ 0.1 keV at the outburst peak) with an X-ray luminosity of L ~ 4 × 10 ^38 erg s ^−1 , labeled EP J005245.1−722843. This supersoft outburst faded very quickly in a week's time. Several emission lines and absorption edges were present in the X-ray spectrum, including deep nitrogen (0.67 keV) and oxygen (0.87 keV) absorption edges. The X-ray emission resembles the supersoft source phase of typical nova outbursts from an accreting white dwarf (WD) in a binary system, despite the X-ray source being historically associated with an O9-B0e massive star exhibiting a 17.55 day periodicity in the optical band. The discovery of this supersoft outburst suggests that EP J005245.1−722843 is a BeWD X-ray binary: an elusive evolutionary stage where two main-sequence massive stars have undergone a common envelope phase and experienced at least two episodes of mass transfer. In addition, the very short duration of the outburst and the presence of Ne features hint at a rather massive, i.e., close to the Chandrasekhar limit, Ne–O WD in the system. |
| format | Article |
| id | doaj-art-a9ddc4dfc8d047bb82e8a1473bea4ec2 |
| institution | Directory of Open Access Journals |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| spelling | doaj-art-a9ddc4dfc8d047bb82e8a1473bea4ec22025-08-20T02:48:37ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019802L3610.3847/2041-8213/ad9580Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud?A. Marino0https://orcid.org/0000-0001-5674-4664H. N. Yang1https://orcid.org/0000-0002-7680-2056F. Coti Zelati2https://orcid.org/0000-0001-7611-1581N. Rea3https://orcid.org/0000-0003-2177-6388S. Guillot4https://orcid.org/0000-0002-6449-106XG. K. Jaisawal5https://orcid.org/0000-0002-6789-2723C. Maitra6https://orcid.org/0000-0002-0766-7313J.-U. Ness7https://orcid.org/0000-0003-0440-7193F. Haberl8https://orcid.org/0000-0002-0107-5237E. Kuulkers9https://orcid.org/0000-0002-5790-7290W. Yuan10H. Feng11L. Tao12https://orcid.org/0000-0002-2705-4338C. Jin13https://orcid.org/0000-0002-2006-1615H. Sun14https://orcid.org/0000-0002-9615-1481W. Zhang15W. Chen16E. P. J. van den Heuvel17https://orcid.org/0000-0002-6417-2018R. Soria18https://orcid.org/0000-0002-4622-796XB. Zhang19https://orcid.org/0000-0002-9725-2524S.-S. Weng20https://orcid.org/0000-0001-7595-1458L. Ji21https://orcid.org/0000-0001-9599-7285G. B. Zhang22https://orcid.org/0000-0001-8630-5435X. Pan23https://orcid.org/0000-0002-6938-3594Z. Lv24C. Zhang25Z. X. Ling26Y. Chen27https://orcid.org/0000-0001-9834-2196S. Jia28https://orcid.org/0000-0002-5203-8321Y. Liu29H. Q. Cheng30D. Y. Li31https://orcid.org/0000-0002-4562-7179K. Gendreau32https://orcid.org/0000-0001-7115-2819M. Ng33https://orcid.org/0000-0002-0940-6563T. Strohmayer34https://orcid.org/0000-0001-7681-5845Institute of Space Sciences (ICE, CSIC) , Campus UAB, Carrer de Can Magrans s/n, 08193, Barcelona, Spain ; marino@ice.csic.es; Institut d’Estudis Espacials de Catalunya (IEEC) , Esteve Terradas 1, RDIT Building, Of. 212 Mediterranean Technology Park (PMT), 08860, Castelldefels, SpainNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; Max-Planck-Institut für extraterrestrische Physik , Gießenbachstraße 1, D-85748 Garching bei München, Germany; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaInstitute of Space Sciences (ICE, CSIC) , Campus UAB, Carrer de Can Magrans s/n, 08193, Barcelona, Spain ; marino@ice.csic.es; Institut d’Estudis Espacials de Catalunya (IEEC) , Esteve Terradas 1, RDIT Building, Of. 212 Mediterranean Technology Park (PMT), 08860, Castelldefels, SpainInstitute of Space Sciences (ICE, CSIC) , Campus UAB, Carrer de Can Magrans s/n, 08193, Barcelona, Spain ; marino@ice.csic.es; Institut d’Estudis Espacials de Catalunya (IEEC) , Esteve Terradas 1, RDIT Building, Of. 212 Mediterranean Technology Park (PMT), 08860, Castelldefels, SpainIRAP , CNRS, 9 avenue du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, FranceDTU Space, Technical University of Denmark , Elektrovej 327-328, DK-2800 Lyngby, DenmarkMax-Planck-Institut für extraterrestrische Physik , Gießenbachstraße 1, D-85748 Garching bei München, GermanyEuropean Space Agency (ESA) , European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, E-28692 Villanueva de la Cañada, Madrid, SpainMax-Planck-Institut für extraterrestrische Physik , Gießenbachstraße 1, D-85748 Garching bei München, GermanyEuropean Space Agency (ESA), European Space Research and Technology Centre (ESTEC) , Keplerlaan 1, 2201 AZ Noordwijk, The NetherlandsNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaKey Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaKey Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cnNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cnNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaAnton Pannekoek Institute for Astronomy, University of Amsterdam , P.O. Box 94249, 1090 GE Amsterdam, The NetherlandsINAF—Osservatorio Astrofisico di Torino , Strada Osservatorio 20, I-10025 Pino Torinese, Italy; Sydney Institute for Astronomy, School of Physics A28, The University of Sydney , Sydney, NSW 2006, Australia; College of Astronomy and Space Sciences, University of the Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNevada Center for Astrophysics, University of Nevada Las Vegas , NV 89154, USA; Department of Physics and Astronomy, University of Nevada Las Vegas , NV 89154, USADepartment of Physics and Institute of Theoretical Physics, Nanjing Normal University , Nanjing, People’s Republic of ChinaSchool of Physics and Astronomy, Sun Yat-sen University , Zhuhai, 519082, People’s Republic of ChinaYunnan Observatories, Chinese Academy of Sciences , Kunming 650216, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cnNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of ChinaKey Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaSchool of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of China; Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cnNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cnNational Astronomical Observatories, Chinese Academy of Sciences , Beijing, 100101, People’s Republic of China ; hnyang@nao.cas.cnAstrophysics Science Division, NASA’s Goddard Space Flight Center , Greenbelt, MD 20771, USAMIT Kavli Institute for Astrophysics and Space Research , Massachusetts Institute of Technology, Cambridge, MA 02139, USAAstrophysics Science Division, NASA’s Goddard Space Flight Center , Greenbelt, MD 20771, USA; Joint Space-Science Institute, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USAOn 2024 May 27, the Wide-field X-ray Telescope on board the Space Sciences, University of Chinese Academy of Einstein Probe (EP) mission detected enhanced X-ray emission from a new transient source in the Small Magellanic Cloud during its commissioning phase. Prompt follow-up with the EP Follow-up X-ray Telescope, the Swift X-ray Telescope. and NICER have revealed a very soft, thermally emitting source ( kT ~ 0.1 keV at the outburst peak) with an X-ray luminosity of L ~ 4 × 10 ^38 erg s ^−1 , labeled EP J005245.1−722843. This supersoft outburst faded very quickly in a week's time. Several emission lines and absorption edges were present in the X-ray spectrum, including deep nitrogen (0.67 keV) and oxygen (0.87 keV) absorption edges. The X-ray emission resembles the supersoft source phase of typical nova outbursts from an accreting white dwarf (WD) in a binary system, despite the X-ray source being historically associated with an O9-B0e massive star exhibiting a 17.55 day periodicity in the optical band. The discovery of this supersoft outburst suggests that EP J005245.1−722843 is a BeWD X-ray binary: an elusive evolutionary stage where two main-sequence massive stars have undergone a common envelope phase and experienced at least two episodes of mass transfer. In addition, the very short duration of the outburst and the presence of Ne features hint at a rather massive, i.e., close to the Chandrasekhar limit, Ne–O WD in the system.https://doi.org/10.3847/2041-8213/ad9580AccretionX-ray binary starsHigh mass x-ray binary starsWhite dwarf starsSmall Magellanic Cloud |
| spellingShingle | A. Marino H. N. Yang F. Coti Zelati N. Rea S. Guillot G. K. Jaisawal C. Maitra J.-U. Ness F. Haberl E. Kuulkers W. Yuan H. Feng L. Tao C. Jin H. Sun W. Zhang W. Chen E. P. J. van den Heuvel R. Soria B. Zhang S.-S. Weng L. Ji G. B. Zhang X. Pan Z. Lv C. Zhang Z. X. Ling Y. Chen S. Jia Y. Liu H. Q. Cheng D. Y. Li K. Gendreau M. Ng T. Strohmayer Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? Accretion X-ray binary stars High mass x-ray binary stars White dwarf stars Small Magellanic Cloud |
| title | Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? |
| title_full | Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? |
| title_fullStr | Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? |
| title_full_unstemmed | Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? |
| title_short | Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? |
| title_sort | einstein probe discovery of ep j005245 1 722843 a rare be white dwarf binary in the small magellanic cloud |
| topic | Accretion X-ray binary stars High mass x-ray binary stars White dwarf stars Small Magellanic Cloud |
| url | https://doi.org/10.3847/2041-8213/ad9580 |
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