unexpected planets beyond pluto their discovery, physical properties, and implications for solar...

Unexpected planets beyond Pluto

their discovery, physical properties, and implications for solar system history

David Rabinowitz Yale University, Center for Astronomy and Astrophysics

Yale: Charles Baltay, Nancy Ellman, Will Emmet, Tom Hurteau, Rochelle Lauer, Suzanne Tourtellote

Indiana University: Jim Musser, Brice Adams, Mark Gebhard

Caltech: Michael E. Brown, Kristina Barkume, Henry Roe, A.H. Bouchez, R. Sari, M. van Dam, R. Campbell, J. Chin, S. Hartman, E. Johansson, R. Lafon, D. LeMignant, P. Stomski, D. Summers, P. Wizinowich

Gemini Observatory : Chad Trujillo

Sedna

Quaoar

Orcus

Pluto (2200 km)

2003 EL61 “Santa”

2005 FY9 “Easter Bunny”

2003 UB313 “Xena”

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x (AU)

y (AU)

Sedna

Xena

Santa

Bunny

Neptune

Uranus

Saturn

-120

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x (AU)

z (AU)

Sedna Xena

Santa

Bunnyecliptic plane

Neptune

Uranus

Saturn

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NeptuneLe Verrier, Galle

1846, 9”

UranusHerschel, 1781, 6”

PlutoTombaugh,

1930, 13”

“Xena”2005, 48”

Kuiper BeltJewitt, Luu 1992, 86”

Sedna2004, 48”

Beta Pictoris

M. Liu, Science 303, 2004

AU MicH-band imaging with Keck Adaptive Optics (0.04” seeing)

(0.1 earth mass)

Where did the mass go ?

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Clyde Tombaugh - 1938

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The reflectance spectrum of 2003 UB313

Type of Surface

Albedo Diameter Pluto Diameters

Fresh snow 90% 2330 km 1.0

Pluto 60% 2860 km 1.3

Charon

(Pluto’s moon)

38% 3550 km 1.5

Most Kuiper Belt Objects

15% 5700 km 2.4

Possible Sizes for “Xena”

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Keck discovery of Xena’s moon, “Gabrielle”

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Easter Bunny

Charon

Rudolph

Santa

Xena

Gabrielle

Keck Laser Guide Star Observations

Xena-Gabrielle to Earth-moon

Earth

Moon

Xena Gabrielle

Xena Gabrielle

Santa (2003 EL61) a squashed planet

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Satellite Discovered around 2003 EL61 (“Santa”)

“Santa”

“Rudolph”

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Radius: 49,000 kmPeriod: 49 days

Rudolph’s orbit

v2/r = MG/r2

M = 4.21x1021 kg