Presentation on theme: "Spectral analysis of Saturn Keio Senior High School Earth Science Club Shun Shinozaki Yutaro Ao Ryosuke Nyui Atsushi Takei."— Presentation transcript:
Spectral analysis of Saturn Keio Senior High School Earth Science Club Shun Shinozaki Yutaro Ao Ryosuke Nyui Atsushi Takei
Objectives 1. To investigate the atmospheric element of Saturn. 2. To calculate the relative velocity between Saturn s ring and the main body.
The spectral image of Saturn Purple the spectrum of Saturns ring Green the spectrum of the main body We dispersed the middle of the Saturn as the upper chart. Image source http://www.astroarts.co.jp/news/2004/ 03/02cassini/index-j.shtml http://www.astroarts.co.jp/news/2004/ 03/02cassini/index-j.shtml the slit Date:2006/11/24 Telescope: Takahashi 30cm reflector Place: Gunma astronomical observatory
Why did we need the spectrum of the Saturn s ring? The ring is mainly composed of ice. Sunlight is either reflected or passes through the ice We hypothesized that the spectrum of the ring would be the same as that of the sun. Consequently, if we compare the spectrum of the main body with that of the ring, we can find the atmospheric element proper to Saturn.
How to investigate 1. By using makali i PC software, we digitized the spectrum image of both the main body and the ring in order to measure their respective brightness. 2. By using BeSpec, we converted the data to obtain spectral intensity, and then processed it through Excel. 3. We calculated the spectral intensity of the main body as well as the ring to fit both spectrums. Then we divided the body s spectral intensity by the ring s spectral intensity to get the reflection rate.
Conclusion As the result of the analysis, we found the absorption line of methane. We can conclude that there must be methane in Saturn s atmosphere. Therefore …
How to calculate relative velocity We compared Body s spectrum with Ring s to investigate the gaps between them. Then we calculated relative velocity by using formula of the Doppler Effect. We compared Hα wavelength at body with same one at Ring to investigate gaps between them by using makali i.
How to calculate relative velocity We determined the center of absolution by Hα. We found out that Body s minimal value was 870 pixels.
How to calculate relative velocity We drew approximate curves, calculated the local minimum and its coordinates. The gap of minimal value is... upper Ring:0.57 pixels lower Ring:0.44 pixels average: about 0.51 pixels one pixel 3.19 wide 3.19×0.51 1.63 Minimum of absorption line (upper Ring s) Minimum of absorption line (lower Ring s) pixels original date polynomial expression original date polynomial expression X coordinate formula of the Doppler Effect λ/λ=v/c( c means the speed of light ) The wavelength of Hα is 6562.81 (3.19 0.51)/6562.81=v/300000 v 74km/s
Conclusion calculated relative velocity in this investigation about 74 km/s the referred date about 18 km/s A big error in calculation Why? Because the observation equipment was low dispersion, so we couldn t observe the Doppler Effect very well.
References Jupiter Spectra Project NASA JPL Spectrum Date Base http://spec.jpl.nasa.gov/ http://astro.ysc.go.jp/saturn-ring-opening-sun- earth.jpg http://www.shokabo.co.jp/sp_e/optical/solar/s aturn/saturn.htm Published by Hamashima book store New Stage Graphical book of Earth Science
Acknowledgment Toshihiko Hamane (Gunma astronomical observatory) Thank you very much for your great help !