Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars
δ Scuti stars are hot, rapid rotators and a poorly understood class of pulsators. Asteroseismology provides the only means with which to probe their interior dynamics. However, their complex and unexplained oscillation patterns restrict analyses to only a small fraction with interpretable pulsations...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/add7df |
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| author | Kunal H. Singh Subrata Kumar Panda Shravan M. Hanasoge Siddharth Dhanpal |
| author_facet | Kunal H. Singh Subrata Kumar Panda Shravan M. Hanasoge Siddharth Dhanpal |
| author_sort | Kunal H. Singh |
| collection | DOAJ |
| description | δ Scuti stars are hot, rapid rotators and a poorly understood class of pulsators. Asteroseismology provides the only means with which to probe their interior dynamics. However, their complex and unexplained oscillation patterns restrict analyses to only a small fraction with interpretable pulsations. Here, we identify 5381 δ Scuti stars from 63 sectors of TESS observations, of which 300 had interpretable oscillations, with 24 showing rotational splittings. We inferred compositions and ages ( τ ) for the 300 stars, finding them in near-zero-age-main-sequence (ZAMS) states, and measured the mean envelope rotation rates (〈 f _rot 〉) for 24 of them. Analyzing their age-dependent rotation, we found that these stars essentially exhibit weak to no spin-down while evolving past the ZAMS across a narrow time span during which they show regular pulsations. A quantitative fit to their spin evolution results in a trend f _rot ( d ^−1 ) ∝ ( τ /Gyr) ^−0.048 ± 0.016 , much slower than the spin-down of cooler late-type stars due to magnetic braking (Skumanich’s law: f _rot ( d ^−1 ) ∝ ( τ /Gyr) ^−0.5 ). Based on stellar evolution calculations, we show that this weak spin-down is consistent with the gradual increase in the moment of inertia. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-7efd7bab4e7f4b7db1d73c6a18c54a8e2025-08-20T03:28:33ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01987217510.3847/1538-4357/add7dfSeismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass StarsKunal H. Singh0https://orcid.org/0009-0007-5514-4553Subrata Kumar Panda1https://orcid.org/0009-0009-1287-6521Shravan M. Hanasoge2https://orcid.org/0000-0003-2896-1471Siddharth Dhanpal3https://orcid.org/0000-0001-8699-3952St. Xaviers College , Fort, Mumbai 400001, Maharashtra, IndiaTata Institute of Fundamental Research , Colaba, Mumbai 400005, Maharashtra, IndiaTata Institute of Fundamental Research , Colaba, Mumbai 400005, Maharashtra, IndiaTata Institute of Fundamental Research , Colaba, Mumbai 400005, Maharashtra, Indiaδ Scuti stars are hot, rapid rotators and a poorly understood class of pulsators. Asteroseismology provides the only means with which to probe their interior dynamics. However, their complex and unexplained oscillation patterns restrict analyses to only a small fraction with interpretable pulsations. Here, we identify 5381 δ Scuti stars from 63 sectors of TESS observations, of which 300 had interpretable oscillations, with 24 showing rotational splittings. We inferred compositions and ages ( τ ) for the 300 stars, finding them in near-zero-age-main-sequence (ZAMS) states, and measured the mean envelope rotation rates (〈 f _rot 〉) for 24 of them. Analyzing their age-dependent rotation, we found that these stars essentially exhibit weak to no spin-down while evolving past the ZAMS across a narrow time span during which they show regular pulsations. A quantitative fit to their spin evolution results in a trend f _rot ( d ^−1 ) ∝ ( τ /Gyr) ^−0.048 ± 0.016 , much slower than the spin-down of cooler late-type stars due to magnetic braking (Skumanich’s law: f _rot ( d ^−1 ) ∝ ( τ /Gyr) ^−0.5 ). Based on stellar evolution calculations, we show that this weak spin-down is consistent with the gradual increase in the moment of inertia.https://doi.org/10.3847/1538-4357/add7dfDelta Scuti variable stars |
| spellingShingle | Kunal H. Singh Subrata Kumar Panda Shravan M. Hanasoge Siddharth Dhanpal Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars The Astrophysical Journal Delta Scuti variable stars |
| title | Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars |
| title_full | Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars |
| title_fullStr | Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars |
| title_full_unstemmed | Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars |
| title_short | Seismic Constraints on the Spin Evolution of Slowly Rotating Young Intermediate-mass Stars |
| title_sort | seismic constraints on the spin evolution of slowly rotating young intermediate mass stars |
| topic | Delta Scuti variable stars |
| url | https://doi.org/10.3847/1538-4357/add7df |
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