Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares
We explore the empirical power-law relationship between X-ray luminosity ( L _X ) and total surface magnetic flux (Φ), established across solar magnetic elements, time- and disk-averaged emission from the Sun, older active stars, and pre-main-sequence (PMS) stars. Previous models of large PMS X-ray...
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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/ada55c |
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| author | Konstantin V. Getman Oleg Kochukhov Joe P. Ninan Eric D. Feigelson Vladimir S. Airapetian Abygail R. Waggoner L. Ilsedore Cleeves Jan Forbrich Sergio A. Dzib Charles J. Law Christian Rab Daniel M. Krolikowski |
| author_facet | Konstantin V. Getman Oleg Kochukhov Joe P. Ninan Eric D. Feigelson Vladimir S. Airapetian Abygail R. Waggoner L. Ilsedore Cleeves Jan Forbrich Sergio A. Dzib Charles J. Law Christian Rab Daniel M. Krolikowski |
| author_sort | Konstantin V. Getman |
| collection | DOAJ |
| description | We explore the empirical power-law relationship between X-ray luminosity ( L _X ) and total surface magnetic flux (Φ), established across solar magnetic elements, time- and disk-averaged emission from the Sun, older active stars, and pre-main-sequence (PMS) stars. Previous models of large PMS X-ray flares, lacking direct magnetic field measurements, showed discrepancies from this baseline law, which MHD simulations attribute to unusually strong magnetic fields during flares. To test this, we used nearly simultaneous Chandra X-ray and HET-HPF near-infrared observations of four young Orion stars, measuring surface magnetic fields during or just after powerful PMS X-ray flares. We also modeled these PMS X-ray flares, incorporating their measured magnetic field strengths. Our findings reveal magnetic field strengths at the stellar surface typical of nonflaring PMS stars, ruling out the need for abnormally strong fields during flares. Both PMS and solar flares deviate from the L _X –Φ law, with PMS flares exhibiting a more pronounced deviation, primarily due to their much larger active regions on the surface and larger flaring loop volumes above the surface compared to their solar counterparts. These deviations likely stem from the fact that powerful flares are driven by magnetic reconnection, while baseline X-ray emission may involve less efficient mechanisms like Alfvén wave heating. Our results also indicate a preference for dipolar magnetic loops in PMS flares, consistent with Zeeman–Doppler imaging of fully convective stars. This requirement for giant dipolar loops aligns with MHD predictions of strong dipoles supported by polar magnetic surface active regions in fast-rotating, fully convective stars. |
| format | Article |
| id | doaj-art-6b9584f4008345fab1379f784e26e293 |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-6b9584f4008345fab1379f784e26e2932025-02-04T06:04:57ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198015710.3847/1538-4357/ada55cMulti-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray FlaresKonstantin V. Getman0https://orcid.org/0000-0002-6137-8280Oleg Kochukhov1https://orcid.org/0000-0003-3061-4591Joe P. Ninan2https://orcid.org/0000-0001-8720-5612Eric D. Feigelson3https://orcid.org/0000-0002-5077-6734Vladimir S. Airapetian4https://orcid.org/0000-0003-4452-0588Abygail R. Waggoner5https://orcid.org/0000-0002-1566-389XL. Ilsedore Cleeves6https://orcid.org/0000-0003-2076-8001Jan Forbrich7https://orcid.org/0000-0001-8694-4966Sergio A. Dzib8https://orcid.org/0000-0001-6010-6200Charles J. Law9https://orcid.org/0000-0003-1413-1776Christian Rab10https://orcid.org/0000-0003-1817-6576Daniel M. Krolikowski11https://orcid.org/0000-0001-9626-0613Department of Astronomy & Astrophysics, Pennsylvania State University , 525 Davey Laboratory, University Park, PA 16802, USA ; kug1@psu.eduDepartment of Physics and Astronomy, Uppsala University , Box 516, 75120 Uppsala, SwedenDepartment of Astronomy and Astrophysics, Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, IndiaDepartment of Astronomy & Astrophysics, Pennsylvania State University , 525 Davey Laboratory, University Park, PA 16802, USA ; kug1@psu.eduAmerican University , 4400 Massachusetts Avenue NW, Washington, DC 20016, USA; NASA/GSFC/SEEC , Greenbelt, MD 20771, USAUniversity of Virginia , Charlottesville, VA 22904, USA; Department of Astronomy, University of Wisconsin-Madison , 475 N Charter Street, Madison, WI 53706, USAUniversity of Virginia , Charlottesville, VA 22904, USACentre for Astrophysics Research, University of Hertfordshire , College Lane, Hatfield, AL10 9AB, UKMax-Planck-Institut fur Radioastronomie (MPIfR) , Auf dem Hugel 69, 53121 Bonn, GermanyUniversity of Virginia , Charlottesville, VA 22904, USAUniversity Observatory , Faculty of Physics, Ludwig-Maximilians-Universitat Munchen, Scheinerstr. 1, D-81679 Munich, Germany; Max-Planck-Institut für Extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, GermanySteward Observatory, The University of Arizona , 933 N. Cherry Avenue, Tucson, AZ 85721, USAWe explore the empirical power-law relationship between X-ray luminosity ( L _X ) and total surface magnetic flux (Φ), established across solar magnetic elements, time- and disk-averaged emission from the Sun, older active stars, and pre-main-sequence (PMS) stars. Previous models of large PMS X-ray flares, lacking direct magnetic field measurements, showed discrepancies from this baseline law, which MHD simulations attribute to unusually strong magnetic fields during flares. To test this, we used nearly simultaneous Chandra X-ray and HET-HPF near-infrared observations of four young Orion stars, measuring surface magnetic fields during or just after powerful PMS X-ray flares. We also modeled these PMS X-ray flares, incorporating their measured magnetic field strengths. Our findings reveal magnetic field strengths at the stellar surface typical of nonflaring PMS stars, ruling out the need for abnormally strong fields during flares. Both PMS and solar flares deviate from the L _X –Φ law, with PMS flares exhibiting a more pronounced deviation, primarily due to their much larger active regions on the surface and larger flaring loop volumes above the surface compared to their solar counterparts. These deviations likely stem from the fact that powerful flares are driven by magnetic reconnection, while baseline X-ray emission may involve less efficient mechanisms like Alfvén wave heating. Our results also indicate a preference for dipolar magnetic loops in PMS flares, consistent with Zeeman–Doppler imaging of fully convective stars. This requirement for giant dipolar loops aligns with MHD predictions of strong dipoles supported by polar magnetic surface active regions in fast-rotating, fully convective stars.https://doi.org/10.3847/1538-4357/ada55cPre-main sequence starsX-ray starsStellar magnetic fieldsStellar x-ray flaresStellar flaresThe Sun |
| spellingShingle | Konstantin V. Getman Oleg Kochukhov Joe P. Ninan Eric D. Feigelson Vladimir S. Airapetian Abygail R. Waggoner L. Ilsedore Cleeves Jan Forbrich Sergio A. Dzib Charles J. Law Christian Rab Daniel M. Krolikowski Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares The Astrophysical Journal Pre-main sequence stars X-ray stars Stellar magnetic fields Stellar x-ray flares Stellar flares The Sun |
| title | Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares |
| title_full | Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares |
| title_fullStr | Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares |
| title_full_unstemmed | Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares |
| title_short | Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares |
| title_sort | multi observatory study of young stellar energetic flares morysef no evidence for abnormally strong stellar magnetic fields after powerful x ray flares |
| topic | Pre-main sequence stars X-ray stars Stellar magnetic fields Stellar x-ray flares Stellar flares The Sun |
| url | https://doi.org/10.3847/1538-4357/ada55c |
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