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Measuring the polarization of disk-integrated lunar reflectance in - - PowerPoint PPT Presentation

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Measuring the polarization of disk-integrated lunar reflectance in the middle ultraviolet Paige Bailey Rice University Mentors: Gregory Holsclaw and Martin Snow August 5, 2010 Paige Bailey, REU Summer 2010: Laboratory for Overview

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SLIDE 1

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Measuring the polarization of disk-integrated lunar reflectance in the middle ultraviolet

Paige Bailey Rice University Mentors: Gregory Holsclaw and Martin Snow

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SLIDE 2

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Overview

– –

–

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SLIDE 3

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Overview of SORCE

  • !
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SLIDE 4

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Motivation for SORCE

  • "##$!%&&'
  • ()!*!)*)+*

*,

  • *!)+

*-./0

  • 1!233 *

*33 * 4./(4(

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SLIDE 5

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

SOLSTICE (A and B)

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!!

  • 3!!)

5667'6& *8%,% !3./69&'6& &,6 !

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SLIDE 6

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

SOLSTICE set-up

  • :
  • ;)85%$8
  • <!!+$!8)+
  • –

(8)**-

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!

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SLIDE 7

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Internal workings of SOLSTICE

Plane grating monochromator design – uses one concave mirror to collimate and focus the spectrum. Only light that leaves the grating at the correct angle will pass through the exit slit.

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SLIDE 8

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Reflection Grating, ctd.

Plane waves, incident on the grating, are diffracted into zero and first order

650 nm 400 nm Zero order

Rotating the grating causes the diffraction angle to change

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SLIDE 9

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Orbit of spacecraft

645 km, 40° inclination,

90 min rotation period

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SLIDE 10

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Phase angle

  • &!
  • 69&8
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  • ?=&8>!

Angle

MOON

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SLIDE 11

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

SOLSTICE Lunar Measurements

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SLIDE 12

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Questions to address:

8!-! !)C

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SLIDE 13

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Polarization

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2

  • D!+8!

)!* !+88)

  • (-6?6*8&!-

p s p s b

I I I I P

+ − =

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SLIDE 14

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Photometry

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+!!)8

– 3!!) – !

)8

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SLIDE 15

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Scattering Plane

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  • (-6

?6*8&!-

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SLIDE 16

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

ECI Coordinates

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SLIDE 17

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

How are effects measured?

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  • D)

8!-

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SLIDE 18

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Roll angle for spacecraft

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  • DC

–

–

+!-

–

#+)8E!

–

8*,,

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SLIDE 19

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Broad range of phase angles

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SLIDE 20

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Albedo at 250nm vs. roll angle

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SLIDE 21

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Why wavelengths were chosen

(-%7&)-8) "F6=7B8

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SLIDE 22

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Ratio at 250 nm and 195 nm

Sun's spectrum is normalized with a Gaussian fit Ratio of sun vs. moon is the reflectance Angles were chosen because the instrument is sensitive to polarization at 250nm, and not at 195 nm

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SLIDE 23

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

What we expected to find

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!8)+-

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  • 3!B88-
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  • D*+8 B
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SLIDE 24

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Lunar polarization

  • Nearly all airless solar

system bodies exhibit this shape of polarization response [Hapke, 1993].

  • The curves are

characterized by a few obvious parameters (P is polarization, V is phase angle):

  • Pmax, Vmax
  • Pmin, Vmin
  • Vi (inversion angle)
  • hi (slope at inversion

angle)

  • This shows that the

magnitude of the polarization is inversely proportional to the albedo (thus, the dark mare exhibit a large polarization).

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SLIDE 25

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

What we found... at first

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SLIDE 26

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Reducing uncertainty of slope

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=&*8!+ 8+!+*!!

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SLIDE 27

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Data filtering

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)*%&*'&*,

  • (-
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SLIDE 28

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Examples of filtering

Phase angle from 0 to 10 Phase angle from 10 to 20 Roll angle vs. Albedo at 250 nm

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SLIDE 29

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Results: Slope vs. Phase Angle

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SLIDE 30

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Questions

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SLIDE 31

August 5, 2010

Paige Bailey, REU Summer 2010: Laboratory for

Acknowledgments

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8!,