Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma
There have been relatively few published long-duration, uninterrupted light curves of magnetic cataclysmic variable stars in which the accreting white dwarf’s rotational frequency is slightly desynchronized from the binary orbital frequency. We report Kepler K2 and TESS observations of two such syst...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astronomical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-3881/aca1a5 |
| _version_ | 1797695796693434368 |
|---|---|
| author | Colin Littlefield D. W. Hoard Peter Garnavich Paula Szkody Paul A. Mason Simone Scaringi Krystian Ilkiewicz Mark R. Kennedy Saul A. Rappaport Rahul Jayaraman |
| author_facet | Colin Littlefield D. W. Hoard Peter Garnavich Paula Szkody Paul A. Mason Simone Scaringi Krystian Ilkiewicz Mark R. Kennedy Saul A. Rappaport Rahul Jayaraman |
| author_sort | Colin Littlefield |
| collection | DOAJ |
| description | There have been relatively few published long-duration, uninterrupted light curves of magnetic cataclysmic variable stars in which the accreting white dwarf’s rotational frequency is slightly desynchronized from the binary orbital frequency. We report Kepler K2 and TESS observations of two such systems. The first, SDSS J084617.11+245344.1, was observed by the Kepler spacecraft for 80 days during Campaign 16 of the K2 mission, and we identify it as a new asynchronous polar with a likely 4.64 hr orbital period. This is significantly longer than any other asynchronous polar, as well as all but several synchronous polars. Its spin and orbital periods beat against each other to produce a conspicuous 6.77-day beat period, across which the system’s accretion geometry gradually changes. The second system in this study, Paloma, was observed by TESS for one sector and was already known to be asynchronous. Until now, there had been an ambiguity in its spin period, but the TESS power spectrum pinpoints a spin period of 2.27 hr. During the resulting 0.7-day spin–orbit beat period, the light curve phased on the spin modulation alternates between being single and double humped. We explore two possible explanations for this behavior: the accretion flow being diverted from one of the poles for part of the beat cycle, or an eclipse of the emitting region responsible for the second hump. |
| first_indexed | 2024-03-12T03:17:22Z |
| format | Article |
| id | doaj.art-bed4791703564eb99ea300e010bca2c0 |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-03-12T03:17:22Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-bed4791703564eb99ea300e010bca2c02023-09-03T14:08:26ZengIOP PublishingThe Astronomical Journal1538-38812023-01-0116524310.3847/1538-3881/aca1a5Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and PalomaColin Littlefield0https://orcid.org/0000-0001-7746-5795D. W. Hoard1Peter Garnavich2https://orcid.org/0000-0003-4069-2817Paula Szkody3https://orcid.org/0000-0003-4373-7777Paul A. Mason4https://orcid.org/0000-0002-5897-3038Simone Scaringi5Krystian Ilkiewicz6https://orcid.org/0000-0002-4005-5095Mark R. Kennedy7https://orcid.org/0000-0001-6894-6044Saul A. Rappaport8https://orcid.org/0000-0003-3182-5569Rahul Jayaraman9https://orcid.org/0000-0002-7778-3117Department of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USA ; clittlef@alumni.nd.edu; Department of Astronomy, University of Washington , Seattle, WA 98195, USA; Bay Area Environmental Research Institute , Moffett Field, CA 94035 USADepartment of Astronomy, University of Washington , Seattle, WA 98195, USADepartment of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USA ; clittlef@alumni.nd.eduDepartment of Astronomy, University of Washington , Seattle, WA 98195, USANew Mexico State University , MSC 3DA, Las Cruces, NM, 88003, USA; Picture Rocks Observatory , 1025 S. Solano Dr., Suite D., Las Cruces, NM 88001, USACentre for Extragalactic Astronomy, Department of Physics, Durham University , South Road, Durham, DH1 3LE, UKCentre for Extragalactic Astronomy, Department of Physics, Durham University , South Road, Durham, DH1 3LE, UK; Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, PolandDepartment of Physics, University College Cork , Cork, Ireland; Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester , M19 9PL, UKDepartment of Physics and Kavli Institute for Astrophysics and Space Research , MIT, Cambridge, MA 02139, USADepartment of Physics and Kavli Institute for Astrophysics and Space Research , MIT, Cambridge, MA 02139, USAThere have been relatively few published long-duration, uninterrupted light curves of magnetic cataclysmic variable stars in which the accreting white dwarf’s rotational frequency is slightly desynchronized from the binary orbital frequency. We report Kepler K2 and TESS observations of two such systems. The first, SDSS J084617.11+245344.1, was observed by the Kepler spacecraft for 80 days during Campaign 16 of the K2 mission, and we identify it as a new asynchronous polar with a likely 4.64 hr orbital period. This is significantly longer than any other asynchronous polar, as well as all but several synchronous polars. Its spin and orbital periods beat against each other to produce a conspicuous 6.77-day beat period, across which the system’s accretion geometry gradually changes. The second system in this study, Paloma, was observed by TESS for one sector and was already known to be asynchronous. Until now, there had been an ambiguity in its spin period, but the TESS power spectrum pinpoints a spin period of 2.27 hr. During the resulting 0.7-day spin–orbit beat period, the light curve phased on the spin modulation alternates between being single and double humped. We explore two possible explanations for this behavior: the accretion flow being diverted from one of the poles for part of the beat cycle, or an eclipse of the emitting region responsible for the second hump.https://doi.org/10.3847/1538-3881/aca1a5DQ Herculis starsAM Herculis starsCataclysmic variable starsWhite dwarf stars |
| spellingShingle | Colin Littlefield D. W. Hoard Peter Garnavich Paula Szkody Paul A. Mason Simone Scaringi Krystian Ilkiewicz Mark R. Kennedy Saul A. Rappaport Rahul Jayaraman Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma The Astronomical Journal DQ Herculis stars AM Herculis stars Cataclysmic variable stars White dwarf stars |
| title | Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma |
| title_full | Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma |
| title_fullStr | Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma |
| title_full_unstemmed | Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma |
| title_short | Kepler K2 and TESS Observations of Two Magnetic Cataclysmic Variables: The New Asynchronous Polar SDSS J084617.11+245344.1 and Paloma |
| title_sort | kepler k2 and tess observations of two magnetic cataclysmic variables the new asynchronous polar sdss j084617 11 245344 1 and paloma |
| topic | DQ Herculis stars AM Herculis stars Cataclysmic variable stars White dwarf stars |
| url | https://doi.org/10.3847/1538-3881/aca1a5 |
| work_keys_str_mv | AT colinlittlefield keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT dwhoard keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT petergarnavich keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT paulaszkody keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT paulamason keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT simonescaringi keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT krystianilkiewicz keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT markrkennedy keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT saularappaport keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma AT rahuljayaraman keplerk2andtessobservationsoftwomagneticcataclysmicvariablesthenewasynchronouspolarsdssj084617112453441andpaloma |