Modelling Neutron-Star Ocean Dynamics
We revisit the calculation of mode oscillations in the ocean of a rotating neutron star, which may be excited during thermonuclear X-ray bursts. Our present theoretical understanding of ocean modes relies heavily on the traditional approximation commonly employed in geophysics. The approximation ele...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-05-01
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| Series: | Universe |
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| Online Access: | https://www.mdpi.com/2218-1997/9/5/226 |
| _version_ | 1797598134548824064 |
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| author | Fabian Gittins Thomas Celora Aru Beri Nils Andersson |
| author_facet | Fabian Gittins Thomas Celora Aru Beri Nils Andersson |
| author_sort | Fabian Gittins |
| collection | DOAJ |
| description | We revisit the calculation of mode oscillations in the ocean of a rotating neutron star, which may be excited during thermonuclear X-ray bursts. Our present theoretical understanding of ocean modes relies heavily on the traditional approximation commonly employed in geophysics. The approximation elegantly decouples the radial and angular sectors of the perturbation problem by neglecting the vertical contribution from the Coriolis force. However, as the implicit assumptions underlying it are not as well understood as they ought to be, we examine the traditional approximation and discuss the associated mode solutions. The results demonstrate that, while the approximation may be appropriate in certain contexts, it may not be accurate for rapidly rotating neutron stars. In addition, using the shallow-water approximation, we show analytically how the solutions that resemble <i>r</i>-modes change their nature in neutron-star oceans to behave like gravity waves. We also outline a simple prescription for lifting Newtonian results in a shallow ocean to general relativity, making the result more realistic. |
| first_indexed | 2024-03-11T03:15:04Z |
| format | Article |
| id | doaj.art-0737544eca4140939fad3e6fab54fddc |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-03-11T03:15:04Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj.art-0737544eca4140939fad3e6fab54fddc2023-11-18T03:34:54ZengMDPI AGUniverse2218-19972023-05-019522610.3390/universe9050226Modelling Neutron-Star Ocean DynamicsFabian Gittins0Thomas Celora1Aru Beri2Nils Andersson3Mathematical Sciences and STAG Research Centre, University of Southampton, Southampton SO17 1BJ, UKMathematical Sciences and STAG Research Centre, University of Southampton, Southampton SO17 1BJ, UKDepartment of Physical Sciences, IISER Mohali, Manauli 140306, Punjab, IndiaMathematical Sciences and STAG Research Centre, University of Southampton, Southampton SO17 1BJ, UKWe revisit the calculation of mode oscillations in the ocean of a rotating neutron star, which may be excited during thermonuclear X-ray bursts. Our present theoretical understanding of ocean modes relies heavily on the traditional approximation commonly employed in geophysics. The approximation elegantly decouples the radial and angular sectors of the perturbation problem by neglecting the vertical contribution from the Coriolis force. However, as the implicit assumptions underlying it are not as well understood as they ought to be, we examine the traditional approximation and discuss the associated mode solutions. The results demonstrate that, while the approximation may be appropriate in certain contexts, it may not be accurate for rapidly rotating neutron stars. In addition, using the shallow-water approximation, we show analytically how the solutions that resemble <i>r</i>-modes change their nature in neutron-star oceans to behave like gravity waves. We also outline a simple prescription for lifting Newtonian results in a shallow ocean to general relativity, making the result more realistic.https://www.mdpi.com/2218-1997/9/5/226asteroseismologyneutron starsoscillationsrotationX-ray bursts |
| spellingShingle | Fabian Gittins Thomas Celora Aru Beri Nils Andersson Modelling Neutron-Star Ocean Dynamics Universe asteroseismology neutron stars oscillations rotation X-ray bursts |
| title | Modelling Neutron-Star Ocean Dynamics |
| title_full | Modelling Neutron-Star Ocean Dynamics |
| title_fullStr | Modelling Neutron-Star Ocean Dynamics |
| title_full_unstemmed | Modelling Neutron-Star Ocean Dynamics |
| title_short | Modelling Neutron-Star Ocean Dynamics |
| title_sort | modelling neutron star ocean dynamics |
| topic | asteroseismology neutron stars oscillations rotation X-ray bursts |
| url | https://www.mdpi.com/2218-1997/9/5/226 |
| work_keys_str_mv | AT fabiangittins modellingneutronstaroceandynamics AT thomascelora modellingneutronstaroceandynamics AT aruberi modellingneutronstaroceandynamics AT nilsandersson modellingneutronstaroceandynamics |