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Sally Seebode Science Educator SMUHSD

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Dean Drumheller, Steve Howell, Don Hoard, Sally Seebode, Darryl Stanford

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Take Data

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Hardware: Losmandy G11 Mount Meade 8 SBIG Self Guided Spectrograph (SGS) ST7XME camera Software: TheSky 6- accurate mount control CCDSoft –image acquisition Maxim DL –image acquisition IRAF –spectra processing

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Raw Data Frame Reduced Spectrum: standard methods using IRAF 3800 – 4600A; 5800 – 6600A

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Equivalent Width Full Width Half Max Velocity Minimum three students make measurements for each spectra, data averaged and plotted.

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Equivalent Widths (eqw): the width of a standardized rectangle representing the area of the absorption line. EQW relates to the flux. Exaggerated for emphasis

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Full Width Half Max (FWHM): the width of the absorption line at half its maximum value. Changes in FWHM indicate velocity variations which relates to the temperature and composition of disk.

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Velocity: Measure the central wavelength to determine if object is moving toward or away from you and at what relative velocity.

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Small portion of data.

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If I knew what I was looking for this would be much easier.

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Student motivation more important than math/science literacy IRAF hard to get on high school computers Teacher collaboration helpful Lots of support for astronomy education: NITARP, AAVSO, Lift Off, Project Astro, etc.

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Variation in absorption of various elements Indicative of varying density of the disk Possible Ring Structure

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Eqw minimum Eqw maximum Leadbeater/Stencel plateaus

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Measure the days of a min or max Find fraction of orbit this represents: width of ring = min or max days/(27.1 * 365) Represent fraction angle (* 360) Knowing the radius 18.1 AU, use small angle approximation (sin or tan) to find ring width 18.1 AU Fraction of orbit = (20 days ) *360 (27.1*365) = 0.73 Ring Width = tan 0.73 * 18.1 = 0.23 AU

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Ring mins and maxs are roughly 0.2 AU

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1990 – S. Ferluga: disk is actually a series of concentric rings with gaps between them (like rings of Saturn) Ferluga (1990, A&A, 238, 270) Our result predict an outer ring at a radius of 3.3AU, a wider ring with radius 2.8 AU, and two small inner rings with a radius near 1.5 AU. These two small rings may represent the one inner ring. Our results are similar to Ferlugas prediction.

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Take data 2 or more times every week Examine the spectra for more information: H alpha emission and absorption components Changing molecular bands (CN, CH) FWHM interpretation

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