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Title: DISCOVERY OF A MAKEMAKEAN MOON

Abstract

We describe the discovery of a satellite in orbit about the dwarf planet (136472) Makemake. This satellite, provisionally designated S/2015 (136472) 1, was detected in imaging data collected with the Hubble Space Telescope ’s Wide Field Camera 3 on UTC 2015 April 27 at 7.80 ± 0.04 mag fainter than Makemake and at a separation of 0.″57. It likely evaded detection in previous satellite searches due to a nearly edge-on orbital configuration, placing it deep within the glare of Makemake during a substantial fraction of its orbital period. This configuration would place Makemake and its satellite near a mutual event season. Insufficient orbital motion was detected to make a detailed characterization of its orbital properties, prohibiting a measurement of the system mass with the discovery data alone. Preliminary analysis indicates that if the orbit is circular, its orbital period must be longer than 12.4 days and must have a semimajor axis ≳21,000 km. We find that the properties of Makemake’s moon suggest that the majority of the dark material detected in the system by thermal observations may not reside on the surface of Makemake, but may instead be attributable to S/2015 (136472) 1 having a uniform dark surface. This “darkmore » moon hypothesis” can be directly tested with future James Webb Space Telescope observations. We discuss the implications of this discovery for the spin state, figure, and thermal properties of Makemake and the apparent ubiquity of trans-Neptunian dwarf planet satellites.« less

Authors:
;  [1];  [2];  [3]
  1. Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)
  2. Lowell Observatory, Flagstaff, AZ (United States)
  3. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
Publication Date:
OSTI Identifier:
22654289
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 825; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CONFIGURATION; DETECTION; DWARF STARS; HYPOTHESIS; MASS; MOON; ORBITS; PLANETS; SATELLITES; SPACE; SPIN; SURFACES; TELESCOPES; THERMODYNAMIC PROPERTIES

Citation Formats

Parker, Alex H., Buie, Marc W., Grundy, Will M., and Noll, Keith S., E-mail: aparker@boulder.swri.edu. DISCOVERY OF A MAKEMAKEAN MOON. United States: N. p., 2016. Web. doi:10.3847/2041-8205/825/1/L9.
Parker, Alex H., Buie, Marc W., Grundy, Will M., & Noll, Keith S., E-mail: aparker@boulder.swri.edu. DISCOVERY OF A MAKEMAKEAN MOON. United States. doi:10.3847/2041-8205/825/1/L9.
Parker, Alex H., Buie, Marc W., Grundy, Will M., and Noll, Keith S., E-mail: aparker@boulder.swri.edu. 2016. "DISCOVERY OF A MAKEMAKEAN MOON". United States. doi:10.3847/2041-8205/825/1/L9.
@article{osti_22654289,
title = {DISCOVERY OF A MAKEMAKEAN MOON},
author = {Parker, Alex H. and Buie, Marc W. and Grundy, Will M. and Noll, Keith S., E-mail: aparker@boulder.swri.edu},
abstractNote = {We describe the discovery of a satellite in orbit about the dwarf planet (136472) Makemake. This satellite, provisionally designated S/2015 (136472) 1, was detected in imaging data collected with the Hubble Space Telescope ’s Wide Field Camera 3 on UTC 2015 April 27 at 7.80 ± 0.04 mag fainter than Makemake and at a separation of 0.″57. It likely evaded detection in previous satellite searches due to a nearly edge-on orbital configuration, placing it deep within the glare of Makemake during a substantial fraction of its orbital period. This configuration would place Makemake and its satellite near a mutual event season. Insufficient orbital motion was detected to make a detailed characterization of its orbital properties, prohibiting a measurement of the system mass with the discovery data alone. Preliminary analysis indicates that if the orbit is circular, its orbital period must be longer than 12.4 days and must have a semimajor axis ≳21,000 km. We find that the properties of Makemake’s moon suggest that the majority of the dark material detected in the system by thermal observations may not reside on the surface of Makemake, but may instead be attributable to S/2015 (136472) 1 having a uniform dark surface. This “dark moon hypothesis” can be directly tested with future James Webb Space Telescope observations. We discuss the implications of this discovery for the spin state, figure, and thermal properties of Makemake and the apparent ubiquity of trans-Neptunian dwarf planet satellites.},
doi = {10.3847/2041-8205/825/1/L9},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 825,
place = {United States},
year = 2016,
month = 7
}
  • Continuing the lunar orbit{close_quote}s 300-year role as gravity{close_quote}s testing ground, laser ranging to the Moon precisely confirms the foundations and structure of general relativity. {copyright} {ital 1996 American Institute of Physics.}
  • The chemical implications of a giant impact model for the origin of the moon are examined, both for the moon and for the earth. The Impactor is taken to be an approximately Mars-sized body. It is argued that the likeliest bulk chemical composition of the moon is quite similar to that of the earth's mantle, and that this composition may be explained in detail if about 80{percent} of the moon came from the primitive earth's mantle after segregation of the earth's core. The other 20{percent} of the moon is modelled as coming from (a) the Impactor, which is constrained tomore » be an oxidized, probably undifferentiated body of roughly CI chondritic composition (on a volatile free basis) and (b) a late stage veneer, with a composition and oxidation state similar to that of the H-group ordinary chondrites. This latter component is the source of all the volatile elements in the moon, which failed to condense from the earth-and Impactor-derived materials; this component constitutes about 4{percent} of the moon. It is argued that Mo may behave as a volatile element under the relatively oxidising conditions necessary for the condensation of the proto-moon. The model accounts satisfactorily for most of the siderophile elements, including Fe, Ni, Co, W, P, and Cu. The relatively well-constrained lunar abundances of V, Cr, and Mn are also accounted for; their depletion in the moon is inherited from the earth's mantle.« less
  • The abundances of V, Cr, and Mn inferred for the mantles of the Earth and Moon decrease in that order and are similar, but are distinct from those inferred for the mantles of the Eucrite Parent Body (EPB) and Shergottite Parent Body (SPB). This similarity between Earth and Moon has been used to suggest that the Moon is derived substantially or entirely from Earth mantle material following terrestrial core formation. To test this hypothesis, the authors have determined the partitioning of V, Cr, and Mn between solid iron metal, S-rich metallic liquid, and synthetic basaltic silicate liquid at 1,260{degree}C andmore » one bar pressure. The sequence of compatibility in the metallic phases is Cr > V > Mn at high oxygen fugacity and V > Cr > Mn at low oxygen fugacities. Solubilities in liquid metal always exceed solubilities in solid metal. These partition coefficients suggest that the abundances of V, Cr, and Mn do not reflect core formation in the Earth. Rather, they are consistent with the relative volatilities of these elements. The similarity in the depletion patterns of V, Cr, and Mn inferred for the mantles of the Earth and Moon is a necessary, but not sufficient, condition for the Moon to have been derived wholly or in part from the Earth's mantle.« less