Sally Seebode Science Educator SMUHSD. Dean Drumheller, Steve Howell, Don Hoard, Sally Seebode,...
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Transcript of Sally Seebode Science Educator SMUHSD. Dean Drumheller, Steve Howell, Don Hoard, Sally Seebode,...
Sally SeebodeScience Educator SMUHSD
Dean Drumheller, Steve Howell, Don Hoard, Sally Seebode, Darryl Stanford
Take Data
Hardware: Losmandy G11 Mount Meade 8” SCT @f/6.3 SBIG Self Guided Spectrograph (SGS) ST7XME cameraSoftware: TheSky 6- accurate mount control CCDSoft –image acquisition Maxim DL –image acquisition IRAF –spectra processing
Raw Data Frame
Reduced Spectrum: standard methods using IRAF3800 – 4600A; 5800 – 6600A
•EquivalentWidth
•Full Width Half
Max•Velocity
Minimum three students make measurements for each spectra, data averaged and plotted.
Equivalent Widths (eqw): the width of a standardized rectangle representing the area of the absorption line. EQW relates to the flux.
Exaggerated for emphasis
Full Width Half Max (FWHM): the width of the absorption line at half it’s maximum value. Changes in FWHM indicate velocity variations which relates to the temperature and composition of disk.
Velocity: Measure the central wavelength to determine if object is moving toward or away from you and at what relative velocity.
Small portion of data.
“If I knew what I was looking for this would be much easier.”
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.
Variation in absorption of various elementsIndicative of varying density of the diskPossible Ring Structure
Eqw minimumEqw maximumLeadbeater/Stencel plateaus
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
Ring mins and maxs are roughly 0.2 AU
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 Ferluga’s
prediction.
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 Ferluga’s
prediction.
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