Asphericity of the Base of the Solar Convection Zone
We have used solar oscillation frequencies and frequency splittings obtained over solar cycles 23 and 24 to investigate whether the base of the solar convection zone shows any departure from spherical symmetry. We used the even-order splitting coefficients, a _2 – a _8 , and estimated the contributi...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad2203 |
| _version_ | 1797266062732951552 |
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| author | Sarbani Basu Sylvain G. Korzennik |
| author_facet | Sarbani Basu Sylvain G. Korzennik |
| author_sort | Sarbani Basu |
| collection | DOAJ |
| description | We have used solar oscillation frequencies and frequency splittings obtained over solar cycles 23 and 24 to investigate whether the base of the solar convection zone shows any departure from spherical symmetry. We used the even-order splitting coefficients, a _2 – a _8 , and estimated the contributions from each one separately. The average asphericity over the two solar cycles was determined using frequencies and splittings obtained with a 9216-day time series. We find that evidence of asphericity is, at best , marginal: the a _2 component is consistent with no asphericity, the a _4 and a _6 components yield results at a level a little greater than 1 σ , while the a _8 component shows a signature below 1 σ . The combined results indicate that the time average of the departure from the spherically symmetric position of the base of the convection zone is ≲0.0001 R _⊙ . We have also used helioseismic data obtained from time series of lengths of 360, 576, 1152, and 2304 days in order to examine the consistency of the results and evaluate whether there is any time variation. We find that the evidence for time variation is statistically marginal in all cases, except for the a _6 component, for which tests consistently yield p -values of less than 0.05. |
| first_indexed | 2024-04-25T00:54:43Z |
| format | Article |
| id | doaj.art-2810314b63174b189499385a3bde1b34 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-04-25T00:54:43Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-2810314b63174b189499385a3bde1b342024-03-11T11:26:26ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-019641810.3847/1538-4357/ad2203Asphericity of the Base of the Solar Convection ZoneSarbani Basu0https://orcid.org/0000-0002-6163-3472Sylvain G. Korzennik1https://orcid.org/0000-0003-1531-1541Department of Astronomy, Yale University , P.O. Box 208101, New Haven, CT 06520-8101, USA ; sarbani.basu@yale.eduCenter for Astrophysics ∣ Harvard & Smithsonian , Cambridge, MA 02138, USAWe have used solar oscillation frequencies and frequency splittings obtained over solar cycles 23 and 24 to investigate whether the base of the solar convection zone shows any departure from spherical symmetry. We used the even-order splitting coefficients, a _2 – a _8 , and estimated the contributions from each one separately. The average asphericity over the two solar cycles was determined using frequencies and splittings obtained with a 9216-day time series. We find that evidence of asphericity is, at best , marginal: the a _2 component is consistent with no asphericity, the a _4 and a _6 components yield results at a level a little greater than 1 σ , while the a _8 component shows a signature below 1 σ . The combined results indicate that the time average of the departure from the spherically symmetric position of the base of the convection zone is ≲0.0001 R _⊙ . We have also used helioseismic data obtained from time series of lengths of 360, 576, 1152, and 2304 days in order to examine the consistency of the results and evaluate whether there is any time variation. We find that the evidence for time variation is statistically marginal in all cases, except for the a _6 component, for which tests consistently yield p -values of less than 0.05.https://doi.org/10.3847/1538-4357/ad2203The SunHelioseismologySolar interiorSolar convective zoneSolar cycle |
| spellingShingle | Sarbani Basu Sylvain G. Korzennik Asphericity of the Base of the Solar Convection Zone The Astrophysical Journal The Sun Helioseismology Solar interior Solar convective zone Solar cycle |
| title | Asphericity of the Base of the Solar Convection Zone |
| title_full | Asphericity of the Base of the Solar Convection Zone |
| title_fullStr | Asphericity of the Base of the Solar Convection Zone |
| title_full_unstemmed | Asphericity of the Base of the Solar Convection Zone |
| title_short | Asphericity of the Base of the Solar Convection Zone |
| title_sort | asphericity of the base of the solar convection zone |
| topic | The Sun Helioseismology Solar interior Solar convective zone Solar cycle |
| url | https://doi.org/10.3847/1538-4357/ad2203 |
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