Direct measurement of the size of the large Kuiper belt object (50000) Quaoar

Michael E. Brown; Chadwick A. Trujillo

doi:10.1086/382513

Direct measurement of the size of the large Kuiper belt object (50000) Quaoar

Michael E. Brown, Chadwick A. Trujillo

Research output: Contribution to journal › Article › peer-review

65 Scopus citations

Abstract

We imaged the recently discovered bright Kuiper belt object (50000) Quaoar with the Hubble Space Telescope High Resolution Camera to directly determine its size. The point-spread function (PSF) of each of 16 images was carefully measured from a field star 13″ from Quaoar, and the expected PSF at the location of Quaoar was convolved with Quaoar's motion vector and a model resolved disk. A least-squares analysis was performed to find the best-fit disk size. The apparent diameter of Quaoar was resolved as 40.4 ± 1.8 milliarcseconds. Accounting for the uncertainty due to an unknown limb-darkening function, the size of Quaoar is 1260 ± 190 km with red and blue albedos of 0.092_-0.023^+0.036 and 0.101 _-0.024^+0.039, respectively. These albedos are significantly higher than the canonically assumed value of 4%. Quaoar is the largest currently known minor planet.

Original language	English (US)
Pages (from-to)	2413-2417
Number of pages	5
Journal	Astronomical Journal
Volume	127
Issue number	4 1780
DOIs	https://doi.org/10.1086/382513
State	Published - Apr 2004
Externally published	Yes

Keywords

Minor planets, asteroids
Techniques: image processing

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/382513

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title = "Direct measurement of the size of the large Kuiper belt object (50000) Quaoar",

abstract = "We imaged the recently discovered bright Kuiper belt object (50000) Quaoar with the Hubble Space Telescope High Resolution Camera to directly determine its size. The point-spread function (PSF) of each of 16 images was carefully measured from a field star 13″ from Quaoar, and the expected PSF at the location of Quaoar was convolved with Quaoar's motion vector and a model resolved disk. A least-squares analysis was performed to find the best-fit disk size. The apparent diameter of Quaoar was resolved as 40.4 ± 1.8 milliarcseconds. Accounting for the uncertainty due to an unknown limb-darkening function, the size of Quaoar is 1260 ± 190 km with red and blue albedos of 0.092-0.023+0.036 and 0.101 -0.024+0.039, respectively. These albedos are significantly higher than the canonically assumed value of 4%. Quaoar is the largest currently known minor planet.",

keywords = "Minor planets, asteroids, Techniques: image processing",

author = "Brown, {Michael E.} and Trujillo, {Chadwick A.}",

year = "2004",

month = apr,

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language = "English (US)",

volume = "127",

pages = "2413--2417",

journal = "Astronomical Journal",

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publisher = "IOP Publishing Ltd.",

number = "4 1780",

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TY - JOUR

T1 - Direct measurement of the size of the large Kuiper belt object (50000) Quaoar

AU - Brown, Michael E.

AU - Trujillo, Chadwick A.

PY - 2004/4

Y1 - 2004/4

N2 - We imaged the recently discovered bright Kuiper belt object (50000) Quaoar with the Hubble Space Telescope High Resolution Camera to directly determine its size. The point-spread function (PSF) of each of 16 images was carefully measured from a field star 13″ from Quaoar, and the expected PSF at the location of Quaoar was convolved with Quaoar's motion vector and a model resolved disk. A least-squares analysis was performed to find the best-fit disk size. The apparent diameter of Quaoar was resolved as 40.4 ± 1.8 milliarcseconds. Accounting for the uncertainty due to an unknown limb-darkening function, the size of Quaoar is 1260 ± 190 km with red and blue albedos of 0.092-0.023+0.036 and 0.101 -0.024+0.039, respectively. These albedos are significantly higher than the canonically assumed value of 4%. Quaoar is the largest currently known minor planet.

AB - We imaged the recently discovered bright Kuiper belt object (50000) Quaoar with the Hubble Space Telescope High Resolution Camera to directly determine its size. The point-spread function (PSF) of each of 16 images was carefully measured from a field star 13″ from Quaoar, and the expected PSF at the location of Quaoar was convolved with Quaoar's motion vector and a model resolved disk. A least-squares analysis was performed to find the best-fit disk size. The apparent diameter of Quaoar was resolved as 40.4 ± 1.8 milliarcseconds. Accounting for the uncertainty due to an unknown limb-darkening function, the size of Quaoar is 1260 ± 190 km with red and blue albedos of 0.092-0.023+0.036 and 0.101 -0.024+0.039, respectively. These albedos are significantly higher than the canonically assumed value of 4%. Quaoar is the largest currently known minor planet.

KW - Minor planets, asteroids

KW - Techniques: image processing

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UR - http://www.scopus.com/inward/citedby.url?scp=2442458649&partnerID=8YFLogxK

U2 - 10.1086/382513

DO - 10.1086/382513

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JO - Astronomical Journal

JF - Astronomical Journal

IS - 4 1780

ER -

Direct measurement of the size of the large Kuiper belt object (50000) Quaoar

Abstract

Keywords

ASJC Scopus subject areas

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