Multiwavelength Observations of the RV Tauri Variable System U Monocerotis: Long-Term Variability Phenomena That Can Be Explained by Binary Interactions with a Circumbinary Disk
| Autor: | Eric M. Schlegel, Joel H. Kastner, Sofia Ramstedt, Patricia T. Boyd, Wouter Vlemmings, Laura D. Vega, Keivan G. Stassun, Laurence Sabin, Rodolfo Montez, Tomasz Kamiński |
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| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Omega Binary stars X-ray astronomy Post-asymptotic giant branch stars Astronomi astrofysik och kosmologi 0103 physical sciences Binary star Astronomy Astrophysics and Cosmology Astrophysics::Solar and Stellar Astrophysics Binary system 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences Physics RV Tauri variable stars Astronomy and Astrophysics Circumstellar matter Orientation (vector space) Stars Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Spectral energy distribution Astrophysics::Earth and Planetary Astrophysics Circumbinary planet Submillimeter astronomy |
| DOI: | 10.48550/arxiv.2103.07330 |
| Popis: | We present X-ray through submillimeter observations of the classical RV Tauri (RVb-type) variable U Mon, a post-AGB binary with a circumbinary disk (CBD). Our SMA observations indicate a CBD diameter of $\lesssim$550 au. Our XMM-Newton observations make U Mon the first RV Tauri variable detected in X-rays. The X-ray emission is characteristic of a hot plasma ($\sim$10 MK), with L$_{X}=5\times10^{30}{\rm erg}~{\rm s}^{-1}$, and we consider its possible origin from U Mon, its companion, and/or binary system interactions. Combining DASCH and AAVSO data, we extend the time-series photometric baseline back to the late 1880s and find evidence that U Mon has secular changes that appear to recur on a timescale of $\sim$60 yr, possibly caused by a feature in the CBD. From literature radial velocities we find that the binary companion is a $\sim$2 M$_{\odot}$ A-type main-sequence star. The orientation of the binary's orbit lies along our line of sight ($\omega = 95^\circ$), such that apastron corresponds to photometric RVb minima, consistent with the post-AGB star becoming obscured by the near side of the CBD. In addition, we find the size of the inner-CBD hole ($\sim$4.5-9 au) to be comparable to the binary separation, implying that one or both stars may interact with the CBD at apastron. The obscuration of the post-AGB star implicates the companion as the likely source of the enhanced H$\alpha$ observed at RVb minima and of the X-ray emission that may arise from accreted material. Comment: 19 pages, 9 figures, 4 tables, in aastex62 format, published in ApJ, NASA news feature available upon request. Light curve in Figure 2 available as "Data behind the Figure" |
| Databáze: | OpenAIRE |
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