PHOTOMETRIC MEASUREMENTS OF H{sub 2}O ICE CRYSTALLINITY ON TRANS-NEPTUNIAN OBJECTS

Journal Article · Wed Aug 10 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/827/1/65· OSTI ID:22679541

Terai, Tsuyoshi ^[1]; Itoh, Yoichi ^[2]; Oasa, Yumiko ^[3]; Furusho, Reiko; Watanabe, Junichi ^[4]

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1. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A‘ohoku Place, Hilo, HI 96720 (United States)
2. Center for Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo-cho, Sayo-gun, Hyogo 679-5313 (Japan)
3. Faculty of Education, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570 (Japan)
4. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

We present a measurement of H{sub 2}O ice crystallinity on the surface of trans-neptunian objects with near-infrared narrow-band imaging. The newly developed photometric technique allows us to efficiently determine the strength of a 1.65 μ m absorption feature in crystalline H{sub 2}O ice. Our data for three large objects—Haumea, Quaoar, and Orcus—which are known to contain crystalline H{sub 2}O ice on the surfaces, show a reasonable result with high fractions of the crystalline phase. It can also be pointed out that if the grain size of H{sub 2}O ice is larger than ∼20 μ m, the crystallinities of these objects are obviously below 1.0, which suggests the presence of the amorphous phase. In particular, Orcus exhibits a high abundance of amorphous H{sub 2}O ice compared to Haumea and Quaoar, possibly indicating a correlation between the bulk density of the bodies and the degree of surface crystallization. We also found the presence of crystalline H{sub 2}O ice on Typhon and 2008 AP{sub 129}, both of which are smaller than the minimum size limit for inducing cryovolcanism as well as a transition from amorphous to crystalline phase through thermal evolution due to the decay of long-lived isotopes.

• OSTI ID: 22679541
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 827; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ABUNDANCE
AMORPHOUS STATE
BULK DENSITY
COMPARATIVE EVALUATIONS
CORRELATIONS
CRYSTALLIZATION
DECAY
GRAIN SIZE
ICE
ISOTOPES
NEPTUNE PLANET
PHOTOMETRY
PLANETS
SATELLITES
SURFACES
WATER