Evidence of non-Solar elemental composition in the clocked X-ray burster SRGA J144459.2$-$604207
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2024
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866917867827494912 |
|---|---|
| author | Dohi, Akira Nishimura, Nobuya Hirai, Ryosuke Takeda, Tomoshi Iwakiri, Wataru Tamagawa, Toru Aoyama, Amira Enoto, Teruaki Iwata, Satoko Kato, Yo Kitaguchi, Takao Mihara, Tatehiro Ota, Naoyuki Takahashi, Takuya Watanabe, Sota Yamasaki, Kaede |
| author_facet | Dohi, Akira Nishimura, Nobuya Hirai, Ryosuke Takeda, Tomoshi Iwakiri, Wataru Tamagawa, Toru Aoyama, Amira Enoto, Teruaki Iwata, Satoko Kato, Yo Kitaguchi, Takao Mihara, Tatehiro Ota, Naoyuki Takahashi, Takuya Watanabe, Sota Yamasaki, Kaede |
| contents | In February and March 2024, a series of many Type I X-ray bursts from the accreting neutron star SRGA J144459.2$-$604207, which has been identified by multiple X-ray satellites, with the first reports coming from INTEGRAL and NinjaSat. These observations reveal that after exhibiting very regular behavior as a ``clocked'' burster, the peak luminosity of the SRGA J144459.2$-$604207 X-ray bursts shows a gradual decline. The observed light curves exhibit a short plateau feature, potentially with a double peak, followed by a rapid decay in the tail-features unlike those seen in previously observed clocked bursters. In this study, we calculate a series of multizone X-ray burst models with various compositions of accreted matter, specifically varying the mass fractions of hydrogen ($X$), helium ($Y$), and heavier CNO elements or metallicity ($Z_{\rm CNO}$). We demonstrate that a model with higher $Z_{\rm CNO}$ and/or lower $X/Y$ compared to the solar values can reproduce the observed behavior of SRGA J144459.2$-$604207. Therefore, we propose that this new X-ray burster is likely the first clocked burster with non-solar elemental compositions. Moreover, based on the X-ray burst light curve morphology in the decline phase observed by NinjaSat, a He-enhanced model with $X/Y \approx 1.5$ seems preferred over high-metallicity cases. We also give a brief discussion on the implications for the neutron star mass, binary star evolution, inclination angle, and the potential for a high-metallicity scenario, the last of which is closely related to the properties of the hot CNO cycle. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_10993 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Evidence of non-Solar elemental composition in the clocked X-ray burster SRGA J144459.2$-$604207 Dohi, Akira Nishimura, Nobuya Hirai, Ryosuke Takeda, Tomoshi Iwakiri, Wataru Tamagawa, Toru Aoyama, Amira Enoto, Teruaki Iwata, Satoko Kato, Yo Kitaguchi, Takao Mihara, Tatehiro Ota, Naoyuki Takahashi, Takuya Watanabe, Sota Yamasaki, Kaede High Energy Astrophysical Phenomena Solar and Stellar Astrophysics Nuclear Theory In February and March 2024, a series of many Type I X-ray bursts from the accreting neutron star SRGA J144459.2$-$604207, which has been identified by multiple X-ray satellites, with the first reports coming from INTEGRAL and NinjaSat. These observations reveal that after exhibiting very regular behavior as a ``clocked'' burster, the peak luminosity of the SRGA J144459.2$-$604207 X-ray bursts shows a gradual decline. The observed light curves exhibit a short plateau feature, potentially with a double peak, followed by a rapid decay in the tail-features unlike those seen in previously observed clocked bursters. In this study, we calculate a series of multizone X-ray burst models with various compositions of accreted matter, specifically varying the mass fractions of hydrogen ($X$), helium ($Y$), and heavier CNO elements or metallicity ($Z_{\rm CNO}$). We demonstrate that a model with higher $Z_{\rm CNO}$ and/or lower $X/Y$ compared to the solar values can reproduce the observed behavior of SRGA J144459.2$-$604207. Therefore, we propose that this new X-ray burster is likely the first clocked burster with non-solar elemental compositions. Moreover, based on the X-ray burst light curve morphology in the decline phase observed by NinjaSat, a He-enhanced model with $X/Y \approx 1.5$ seems preferred over high-metallicity cases. We also give a brief discussion on the implications for the neutron star mass, binary star evolution, inclination angle, and the potential for a high-metallicity scenario, the last of which is closely related to the properties of the hot CNO cycle. |
| title | Evidence of non-Solar elemental composition in the clocked X-ray burster SRGA J144459.2$-$604207 |
| topic | High Energy Astrophysical Phenomena Solar and Stellar Astrophysics Nuclear Theory |
| url | https://arxiv.org/abs/2411.10993 |