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An Ongoing Mid-infrared Outburst in the White Dwarf 0145+234: Catching in Action the Tidal Disruption of an Exoasteroid?

Wang, Ting-gui and Jiang, Ning and Ge, Jian and Cutri, Roc M. and Jiang, Peng and Sheng, Zhengfeng and Zhou, Hongyan and Bauer, James and Mainzer, Amy and Wright, Edward L. (2019) An Ongoing Mid-infrared Outburst in the White Dwarf 0145+234: Catching in Action the Tidal Disruption of an Exoasteroid? Astrophysical Journal Letters, 886 (1). Art. No. L5. ISSN 2041-8213. https://resolver.caltech.edu/CaltechAUTHORS:20191114-140106877

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Abstract

We report the detection of a large-amplitude MIR outburst in the white dwarf (WD) 0145+234 in the NEOWISE Survey data. The source had a stable MIR flux before 2018, and was brightened by about 1.0 magnitude in the W1 and W2 bands within half a year and has been continuously brightening since then. No significant variations are found in the optical photometry data during the same period. This suggests that this MIR outburst is caused by recent replenishing or redistribution of dust, rather than intrinsic variations of the WD. Spectral energy distribution modeling of 0145+234 suggests that there was already a dust disk around the WD in the quiescent state, and both of the temperature and surface area of the disk evolved rapidly since the outburst. The dust temperature was ≃1770 K in the initial rising phase, close to the sublimation temperature of silicate grains, and gradually cooled down to around 1150 K, while the surface area increased by a factor of about six during the same period. The inferred closest distance of dust to the WD is within the tidal disruption radius of a gravitationally bounded asteroid. We estimated the dust mass to be between 3 × 10¹⁵ and 3 × 10¹⁷ ρ/(1 g cm⁻³) kg for silicate grains of a power-law size distribution with a high cutoff size from 0.1 to 1000 μm. We interpret this as a possible tidal breakup of an exoasteroid by the WD. Further follow-up observations of this rare event may provide insights on the origin of dust disk and metal pollution in some WDs.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/2041-8213/ab53edDOIArticle
https://arxiv.org/abs/1910.04314arXivDiscussion Paper
ORCID:
AuthorORCID
Wang, Ting-gui0000-0002-1517-6792
Jiang, Ning0000-0002-7152-3621
Cutri, Roc M.0000-0002-0077-2305
Jiang, Peng0000-0002-5387-7952
Sheng, Zhengfeng0000-0001-6938-8670
Zhou, Hongyan0000-0003-1956-9021
Wright, Edward L.0000-0001-5058-1593
Additional Information:© 2019 The American Astronomical Society. Received 2019 September 17; revised 2019 November 2; accepted 2019 November 4; published 2019 November 14. We thank the referee for constructive comments. This work is supported by Chinese Science Foundation (NSFC-11833007,11421303). This research makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This research also makes use of data products from NEOWISE-R, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of the National Aeronautics and Space Administration. This research has made use of the NASA/ IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology.
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China11833007
National Natural Science Foundation of China11421303
NASA/JPL/CaltechUNSPECIFIED
Subject Keywords:White dwarf stars; Circumstellar dust; Infrared excess; Variable radiation sources
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: White dwarf stars (1799); Circumstellar dust (236); Infrared excess (788); Variable radiation sources (1759)
Record Number:CaltechAUTHORS:20191114-140106877
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20191114-140106877
Official Citation:Ting-gui Wang et al 2019 ApJL 886 L5
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99846
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:14 Nov 2019 22:31
Last Modified:14 Nov 2019 22:31

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