Academic Journal
Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud?
| Title: | Einstein Probe Discovery of EP J005245.1−722843: A Rare Be–White Dwarf Binary in the Small Magellanic Cloud? |
|---|---|
| Authors: | 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 |
| Source: | The Astrophysical Journal Letters, Vol 980, Iss 2, p L36 (2025) |
| Publisher Information: | IOP Publishing, 2025. |
| Publication Year: | 2025 |
| Collection: | LCC:Astrophysics |
| Subject Terms: | Accretion, X-ray binary stars, High mass x-ray binary stars, White dwarf stars, Small Magellanic Cloud, Astrophysics, QB460-466 |
| More Details: | 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. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 2041-8213 2041-8205 |
| Relation: | https://doaj.org/toc/2041-8205 |
| DOI: | 10.3847/2041-8213/ad9580 |
| Access URL: | https://doaj.org/article/a9ddc4dfc8d047bb82e8a1473bea4ec2 |
| Accession Number: | edsdoj.9ddc4dfc8d047bb82e8a1473bea4ec2 |
| Database: | Directory of Open Access Journals |
| ISSN: | 20418213 20418205 |
|---|---|
| DOI: | 10.3847/2041-8213/ad9580 |
| Published in: | The Astrophysical Journal Letters |
| Language: | English |