Accretion onto WD 2226$-$210, the central star of the Helix Nebula
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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866909424308715520 |
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| author | Estrada-Dorado, S. Guerrero, M. A. Toalá, J. A. Maldonado, R. F. Lora, V. Vasquez-Torres, D. A. Chu, Y. -H. |
| author_facet | Estrada-Dorado, S. Guerrero, M. A. Toalá, J. A. Maldonado, R. F. Lora, V. Vasquez-Torres, D. A. Chu, Y. -H. |
| contents | The central star of the Helix Nebula, WD 2226$-$210 presents enigmatic hard X-ray emission and mid-IR excess. The latter has been attributed to a dusty disk or a cloud-like structure around WD 2226$-$210 formed from material of Kuiper Belt-like or comet-like objects in highly eccentric orbits. We present here a detailed analysis of multi-epoch Chandra and XMM-Newton X-ray observations of WD 2226$-$210, comparing these to previous Einstein and ROSAT data. The luminosity of the hard X-ray component of WD 2226$-$210 has remained basically constant in the decade from 1992 to 2002, with very subtle evidence for variability in timescales of hours. Under the assumption that the X-ray emission from WD 2226$-$210 is due to accretion of material, an accretion rate of $\dot{M}\approx10^{-10}$ M$_\odot$ yr$^{-1}$ is estimated. The origin of the material accreted by WD 2226$-$210 is uncertain, and can be attributed to the disk-like structure around it or to a sub-stellar donor companion. The accretion rate proposed for the continuous replenishment by bombardment of the mid-IR-emitting structure around WD 2226$-$210 cannot match that required by the X-ray emission. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_07863 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Accretion onto WD 2226$-$210, the central star of the Helix Nebula Estrada-Dorado, S. Guerrero, M. A. Toalá, J. A. Maldonado, R. F. Lora, V. Vasquez-Torres, D. A. Chu, Y. -H. Solar and Stellar Astrophysics High Energy Astrophysical Phenomena The central star of the Helix Nebula, WD 2226$-$210 presents enigmatic hard X-ray emission and mid-IR excess. The latter has been attributed to a dusty disk or a cloud-like structure around WD 2226$-$210 formed from material of Kuiper Belt-like or comet-like objects in highly eccentric orbits. We present here a detailed analysis of multi-epoch Chandra and XMM-Newton X-ray observations of WD 2226$-$210, comparing these to previous Einstein and ROSAT data. The luminosity of the hard X-ray component of WD 2226$-$210 has remained basically constant in the decade from 1992 to 2002, with very subtle evidence for variability in timescales of hours. Under the assumption that the X-ray emission from WD 2226$-$210 is due to accretion of material, an accretion rate of $\dot{M}\approx10^{-10}$ M$_\odot$ yr$^{-1}$ is estimated. The origin of the material accreted by WD 2226$-$210 is uncertain, and can be attributed to the disk-like structure around it or to a sub-stellar donor companion. The accretion rate proposed for the continuous replenishment by bombardment of the mid-IR-emitting structure around WD 2226$-$210 cannot match that required by the X-ray emission. |
| title | Accretion onto WD 2226$-$210, the central star of the Helix Nebula |
| topic | Solar and Stellar Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2412.07863 |