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Title: Searching for Planet Nine with Coadded WISE and NEOWISE-Reactivation Images

Abstract

A distant, as yet unseen ninth planet has been invoked to explain various observations of the outer solar system. While such a "Planet Nine," if it exists, is most likely to be discovered via reflected light in the optical, it may emit much more strongly at 3-5 μm than simple blackbody predictions would suggest, depending on its atmospheric properties. As a result, Planet Nine may be detectable at 3.4 μm with the Wide-field Infrared Survey Explorer, but single exposures are too shallow except at relatively small distances ($${d}_{9}\lesssim 430$$ au). In this paper, we develop a method to search for Planet Nine far beyond the W1 single-exposure sensitivity, to distances as large as 800 au, using inertial coadds of W1 exposures binned into ~1 day intervals. We apply our methodology to a ~2000 square degree testbed sky region which overlaps a southern segment of Planet Nine's anticipated orbital path. We do not detect a plausible Planet Nine candidate, but are able to derive a detailed completeness curve, ruling out its presence within the parameter space searched at W1 < 16.66 (90% completeness). Our method uses all publicly available W1 imaging, spanning 2010 January to 2015 December, and will become more sensitive with future NEOWISE-Reactivation releases of additional W1 exposures. Finally, we anticipate that our method will be applicable to the entire high Galactic latitude sky, and we will extend our search to that full footprint in the near future.

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [4]; ORCiD logo [2]
  1. Berkeley Center for Cosmological Physics, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Univ. of Utah, Salt Lake City, UT (United States)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. Smithsonian Astrophysical Observatory, Cambridge, MA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1379711
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Astronomical Journal (Online)
Additional Journal Information:
Journal Name: Astronomical Journal (Online); Journal Volume: 153; Journal Issue: 2; Journal ID: ISSN 1538-3881
Publisher:
IOP Publishing - AAAS
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; detection of planets and satellites; image processing techniques

Citation Formats

Meisner, Aaron M., Bromley, Benjamin C., Nugent, Peter E., Schlegel, David J., Kenyon, Scott J., Schlafly, Edward F., and Dawson, Kyle S.. Searching for Planet Nine with Coadded WISE and NEOWISE-Reactivation Images. United States: N. p., 2017. Web. doi:10.3847/1538-3881/153/2/65.
Meisner, Aaron M., Bromley, Benjamin C., Nugent, Peter E., Schlegel, David J., Kenyon, Scott J., Schlafly, Edward F., & Dawson, Kyle S.. Searching for Planet Nine with Coadded WISE and NEOWISE-Reactivation Images. United States. doi:10.3847/1538-3881/153/2/65.
Meisner, Aaron M., Bromley, Benjamin C., Nugent, Peter E., Schlegel, David J., Kenyon, Scott J., Schlafly, Edward F., and Dawson, Kyle S.. Wed . "Searching for Planet Nine with Coadded WISE and NEOWISE-Reactivation Images". United States. doi:10.3847/1538-3881/153/2/65. https://www.osti.gov/servlets/purl/1379711.
@article{osti_1379711,
title = {Searching for Planet Nine with Coadded WISE and NEOWISE-Reactivation Images},
author = {Meisner, Aaron M. and Bromley, Benjamin C. and Nugent, Peter E. and Schlegel, David J. and Kenyon, Scott J. and Schlafly, Edward F. and Dawson, Kyle S.},
abstractNote = {A distant, as yet unseen ninth planet has been invoked to explain various observations of the outer solar system. While such a "Planet Nine," if it exists, is most likely to be discovered via reflected light in the optical, it may emit much more strongly at 3-5 μm than simple blackbody predictions would suggest, depending on its atmospheric properties. As a result, Planet Nine may be detectable at 3.4 μm with the Wide-field Infrared Survey Explorer, but single exposures are too shallow except at relatively small distances (${d}_{9}\lesssim 430$ au). In this paper, we develop a method to search for Planet Nine far beyond the W1 single-exposure sensitivity, to distances as large as 800 au, using inertial coadds of W1 exposures binned into ~1 day intervals. We apply our methodology to a ~2000 square degree testbed sky region which overlaps a southern segment of Planet Nine's anticipated orbital path. We do not detect a plausible Planet Nine candidate, but are able to derive a detailed completeness curve, ruling out its presence within the parameter space searched at W1 < 16.66 (90% completeness). Our method uses all publicly available W1 imaging, spanning 2010 January to 2015 December, and will become more sensitive with future NEOWISE-Reactivation releases of additional W1 exposures. Finally, we anticipate that our method will be applicable to the entire high Galactic latitude sky, and we will extend our search to that full footprint in the near future.},
doi = {10.3847/1538-3881/153/2/65},
journal = {Astronomical Journal (Online)},
number = 2,
volume = 153,
place = {United States},
year = {Wed Jan 11 00:00:00 EST 2017},
month = {Wed Jan 11 00:00:00 EST 2017}
}

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