TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles
Transiting Exoplanet Survey Satellite (TESS) photometry of the polars AM Herculis (AM Her) and AR Ursae Majoris (AR UMa) is presented, along with high-speed photometry. AM Her shows a variety of high states with frequent transitions between them. TESS photometry of AR UMa in the low state reveals no...
| Main Authors: | , , , , , , , , , , , , , |
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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/ad27d7 |
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| author | Paul A. Mason Pasi Hakala Kinwah Wu Paul E. Barrett Krystian Iłkiewicz Colin Littlefield Lorena C. Monroy Hasan C. Sezer Francisco Jablonski Peter Garnavich Paula Szkody Gavin Ramsay Christopher Duffy Simone Scaringi |
| author_facet | Paul A. Mason Pasi Hakala Kinwah Wu Paul E. Barrett Krystian Iłkiewicz Colin Littlefield Lorena C. Monroy Hasan C. Sezer Francisco Jablonski Peter Garnavich Paula Szkody Gavin Ramsay Christopher Duffy Simone Scaringi |
| author_sort | Paul A. Mason |
| collection | DOAJ |
| description | Transiting Exoplanet Survey Satellite (TESS) photometry of the polars AM Herculis (AM Her) and AR Ursae Majoris (AR UMa) is presented, along with high-speed photometry. AM Her shows a variety of high states with frequent transitions between them. TESS photometry of AR UMa in the low state reveals no evidence of accretion, while the McDonald 2.1 m telescope caught AR UMa in its high accretion state. Roche-lobe overflow is shut off during low states of AR UMa, while accretion often still takes place during low states of AM Her. We derive inclinations of 50° and 70° for AM Her and AR UMa respectively. To model the high-state light curves of AM Her, we employ a self-organized map light-curve classification scheme to establish common accretion configurations. The cyclotron radiation properties then allow the production of emission region maps on the surface of the white dwarf. The accretion geometry of AM Her is most consistent with a multipolar field structure. The high-state photometry of AR UMa has stochastic accretion flaring, which we attribute to magnetically buffeted mass transfer through the inner Lagrangian point L1. To consider this possibility, we examine the magnetism of both stars and argue that the local magnetic field near L1 can initiate short-lived accretion events and affect transitions between high and low accretion states in both AM Her and AR UMa. In particular, AR UMa has the low state as its default, while AM Her and most other active polars are in the high state by default. |
| first_indexed | 2024-04-24T11:32:42Z |
| format | Article |
| id | doaj.art-0977d91430e944688595f44e8333e07b |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-04-24T11:32:42Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-0977d91430e944688595f44e8333e07b2024-04-10T08:10:50ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196519610.3847/1538-4357/ad27d7TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty CyclesPaul A. Mason0https://orcid.org/0000-0002-5897-3038Pasi Hakala1Kinwah Wu2https://orcid.org/0000-0002-7568-8765Paul E. Barrett3https://orcid.org/0000-0002-8456-1424Krystian Iłkiewicz4https://orcid.org/0000-0002-4005-5095Colin Littlefield5https://orcid.org/0000-0001-7746-5795Lorena C. Monroy6Hasan C. Sezer7Francisco Jablonski8https://orcid.org/0000-0002-0386-2306Peter Garnavich9https://orcid.org/0000-0003-4069-2817Paula Szkody10https://orcid.org/0000-0003-4373-7777Gavin Ramsay11https://orcid.org/0000-0001-8722-9710Christopher Duffy12https://orcid.org/0000-0001-6662-0200Simone Scaringi13https://orcid.org/0000-0001-5387-7189New Mexico State University , MSC 3DA, Las Cruces, NM 88003, USA ; pmason@nmsu.edu; Picture Rocks Observatory , 1025 S. Solano Dr. Suite D., Las Cruces, NM 88001, USAFinnish Centre for Astronomy with ESO, Quantum, Vesilinnantie 5, FI-20014, University of Turku , FinlandMullard Space Science Laboratory, University College London , Holmbury St. Mary, Surrey RH5 6NT, UKDepartment of Physics, The George Washington University , Washington, DC 20052, USACentre for Extragalactic Astronomy, Department of Physics, Durham University , South Road, Durham DH1 3LE, UK; Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warsaw, PolandBay Area Environmental Research Institute , Moffett Field, CA 94035, USAPicture Rocks Observatory , 1025 S. Solano Dr. Suite D., Las Cruces, NM 88001, USAPicture Rocks Observatory , 1025 S. Solano Dr. Suite D., Las Cruces, NM 88001, USAInstituto Nacional de Pesquisas Espaciais , Av. dos Astronautas 1758, São José dos Campos, SP 12227-010, BrazilDepartment of Physics, University of Notre Dame , Notre Dame, IN 46556, USADepartment of Astronomy, University of Washington , Seattle, WA 98195, USAArmagh Observatory and Planetarium , College Hill, Armagh, UKArmagh Observatory and Planetarium , College Hill, Armagh, UK; Department of Physics, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, UKCentre for Extragalactic Astronomy, Department of Physics, Durham University , South Road, Durham DH1 3LE, UKTransiting Exoplanet Survey Satellite (TESS) photometry of the polars AM Herculis (AM Her) and AR Ursae Majoris (AR UMa) is presented, along with high-speed photometry. AM Her shows a variety of high states with frequent transitions between them. TESS photometry of AR UMa in the low state reveals no evidence of accretion, while the McDonald 2.1 m telescope caught AR UMa in its high accretion state. Roche-lobe overflow is shut off during low states of AR UMa, while accretion often still takes place during low states of AM Her. We derive inclinations of 50° and 70° for AM Her and AR UMa respectively. To model the high-state light curves of AM Her, we employ a self-organized map light-curve classification scheme to establish common accretion configurations. The cyclotron radiation properties then allow the production of emission region maps on the surface of the white dwarf. The accretion geometry of AM Her is most consistent with a multipolar field structure. The high-state photometry of AR UMa has stochastic accretion flaring, which we attribute to magnetically buffeted mass transfer through the inner Lagrangian point L1. To consider this possibility, we examine the magnetism of both stars and argue that the local magnetic field near L1 can initiate short-lived accretion events and affect transitions between high and low accretion states in both AM Her and AR UMa. In particular, AR UMa has the low state as its default, while AM Her and most other active polars are in the high state by default.https://doi.org/10.3847/1538-4357/ad27d7Magnetic starsWhite dwarf starsCataclysmic variable starsStellar accretionAccretion |
| spellingShingle | Paul A. Mason Pasi Hakala Kinwah Wu Paul E. Barrett Krystian Iłkiewicz Colin Littlefield Lorena C. Monroy Hasan C. Sezer Francisco Jablonski Peter Garnavich Paula Szkody Gavin Ramsay Christopher Duffy Simone Scaringi TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles The Astrophysical Journal Magnetic stars White dwarf stars Cataclysmic variable stars Stellar accretion Accretion |
| title | TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles |
| title_full | TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles |
| title_fullStr | TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles |
| title_full_unstemmed | TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles |
| title_short | TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles |
| title_sort | tess photometry of am her and ar uma binary parameters cyclotron emission modeling and mass transfer duty cycles |
| topic | Magnetic stars White dwarf stars Cataclysmic variable stars Stellar accretion Accretion |
| url | https://doi.org/10.3847/1538-4357/ad27d7 |
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