Polluting White Dwarfs with Oort Cloud Comets
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866914748195405824 |
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| author | Pham, Dang Rein, Hanno |
| author_facet | Pham, Dang Rein, Hanno |
| contents | Observations point to old white dwarfs (WDs) accreting metals at a relatively constant rate over 8~Gyrs. Exo-Oort clouds around WDs have been proposed as potential reservoirs of materials, with galactic tide as a mechanism to deliver distant comets to the WD's Roche limit. In this work, we characterise the dynamics of comets around a WD with a companion having semi-major axes on the orders of 10 - 100 AU. We develop simulation techniques capable of integrating a large number ($10^8$) of objects over a 1 Gyr timescale. Our simulations include galactic tide and are capable of resolving close-interactions with a massive companion. Through simulations, we study the accretion rate of exo-Oort cloud comets into a WD's Roche limit. We also characterise the dynamics of precession and scattering induced on a comet by a massive companion. We find that (i) WD pollution by an exo-Oort cloud can be sustained over a Gyr timescale, (ii) an exo-Oort cloud with structure like our own Solar System's is capable of delivering materials into an isolated WD with pollution rate $\sim 10^8 \mathrm{~g~s^{-1}}$, (iii) adding a planetary-mass companion reduces the pollution rate to $\sim 10^7 \mathrm{~g~s^{-1}}$, and (iv) if the companion is stellar-mass, with $M_p \gtrsim 0.1 M_\odot$, the pollution rate reduces to $\sim 3 \times 10^5 \mathrm{~g~s^{-1}}$ due to a combination of precession induced on a comet by the companion, a strong scattering barrier, and low-likelihood of direct collisions of comets with the companion. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_07160 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Polluting White Dwarfs with Oort Cloud Comets Pham, Dang Rein, Hanno Earth and Planetary Astrophysics Instrumentation and Methods for Astrophysics Solar and Stellar Astrophysics Observations point to old white dwarfs (WDs) accreting metals at a relatively constant rate over 8~Gyrs. Exo-Oort clouds around WDs have been proposed as potential reservoirs of materials, with galactic tide as a mechanism to deliver distant comets to the WD's Roche limit. In this work, we characterise the dynamics of comets around a WD with a companion having semi-major axes on the orders of 10 - 100 AU. We develop simulation techniques capable of integrating a large number ($10^8$) of objects over a 1 Gyr timescale. Our simulations include galactic tide and are capable of resolving close-interactions with a massive companion. Through simulations, we study the accretion rate of exo-Oort cloud comets into a WD's Roche limit. We also characterise the dynamics of precession and scattering induced on a comet by a massive companion. We find that (i) WD pollution by an exo-Oort cloud can be sustained over a Gyr timescale, (ii) an exo-Oort cloud with structure like our own Solar System's is capable of delivering materials into an isolated WD with pollution rate $\sim 10^8 \mathrm{~g~s^{-1}}$, (iii) adding a planetary-mass companion reduces the pollution rate to $\sim 10^7 \mathrm{~g~s^{-1}}$, and (iv) if the companion is stellar-mass, with $M_p \gtrsim 0.1 M_\odot$, the pollution rate reduces to $\sim 3 \times 10^5 \mathrm{~g~s^{-1}}$ due to a combination of precession induced on a comet by the companion, a strong scattering barrier, and low-likelihood of direct collisions of comets with the companion. |
| title | Polluting White Dwarfs with Oort Cloud Comets |
| topic | Earth and Planetary Astrophysics Instrumentation and Methods for Astrophysics Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2404.07160 |