1. Figure 2 Spectral Analysis of Jupiter’s Atmosphere with Hubble Telescope Data Spectral Analysis of Jupiter’s Atmosphere with Hubble Telescope Data : Student Researchers : Brendan Smyth, Jose Fernandez, Niurka Valera, and Jaquelin Erazo Faculty Mentor: Dr. James Frost Science Advisor: Dr. Barbara Carlson, Senior Scientist, NASA Goddard Institute for Space Studies LaGuardia Community College: 31-10 Thomson Avenue, Long Island City, New York 11101 Abstract Hubble Telescope Images of Jupiter at Various Wavelengths Hubble Telescope Images of Jupiter at Various Wavelengths 218 nm 673nm 890nm Figure 1 Our research concerns the study of Jupiter’s atmosphere through spectral analysis. In particular Jupiter’s “Great Dark Spot”, which is roughly twice the size of Earth, located near the north pole of Jupiter. The phenomenon that is the great dark spot is ephemeral, and was only observed for two short periods of time. First it was captured in 1997 by the Hubble Space Telescope using its Wideview Planetary Camera, and then again in 2000 by NASA’s Cassini flyby of Jupiter. The Great Dark Spot was observed by Hubble Space Telescope in both September and November of 1997, at wavelengths of 218, 255, 336, 410, 673, 890, and 953 nanometers. Using the programming software IDL(Interactive Data Language), we are taking this September and November data and performing a spectral analysis of each wavelength at different locations on the planet. Creating spectral plots for each region of Jupiter (north pole, south pole, equator, and the dark spot) as a function of the different wavelengths at different CML locations. In performing this spectral analysis of the different regions of Jupiter’s atmosphere and the great dark spot, we will help bring about a better understanding of Jupiter’s atmosphere. The results show that as we move towards the poles the concentration of aerosols increases. Also, there are differences in the concentration and composition of the aerosols in the north and in the south poles. The aerosols in the South pole are thicker than the ones in the North. We also found that the aerosols in the North were the same all around with respect to longitude, whereas in the South pole they are more concentrated at CML=0. The data analysis of the Great Dark Spot showed no differences from that of any other region. Jupiter’s Aerosols‘ appear dark in the polar regions in the near ultraviolet zone at 218 nm (at the mbar region), because aerosols are highly absorbent in the ultraviolet spectrum. At 890 nm (Methane Absorption Band), which shows the top of Jupiter’s stratosphere (0.5 bar region), the aerosols appear bright due to high reflectivity. At 673 nm (2 bars,visible light) the aerosols appear to be transparent. Due to Raleigh scattering 218 nm light only shows the top of the atmosphere, while the 673 shows clouds much deeper down in the atmosphere. What are Aerosols? Aerosols are tiny particles suspended in the air that reflect and/or absorb energy in form of light. These tiny particles in earth come from distinct sources, both natural and man made. Today they remain the largest unknown in the study of climate prediction and development. However, in the solar system Earth is not the only planet that has them. Images from the Hubble Space telescope at different wavelengths give us the impression that these particles which reflect light are present throughout Jupiter’s atmosphere, in particular the two poles and the equator. We believe that understanding the physical and optical properties of these particles in Jupiter can give us a better picture of the functions of aerosols in Earth. Methodology In order to determine the makeup of Jupiter’s atmosphere and the concentration of aerosols throughout it, we performed a spectral analysis of the atmosphere. The Hubble telescope images at the 7 different wavelengths are really plots of the intensity of the light reflected or absorbed by the particles at each point in the atmosphere. Jupiter at 890 nm Image displayed as a graph of intensities Before choosing which points to plot and create spectral graphs, we created an image of the ratio between 410 nm and 218 nm to help create easy to see distinctions between points in the atmosphere. This ratio in particular reveals the great dark spot and auroral ovals of Jupiter very clearly. The different ratios, displayed as different colors, give us a way to distinguish what sets of points we care and don’t care about plotting. Once the ratio image is created at the particular CML, spectral plots are created for the different regions of the atmosphere. Because every molecule or element, including aerosols, have particular spectrographs, we can begin to see what concentrations of particles exist where in the atmosphere. Intensity Wavelength (nm) Shown above is the spectral plot of the southern aurora of Jupiter at CML=0. The average intensities at each wavelength were taken, with the standard deviation shown by the error bars on the plot. As can be seen above, the substance is highly absorbent in the UV region, and highly reflective at the Methane Absorption Band, suggesting that the Aurora contains a high concentration of aerosols. Data and Results Using the color ratio between the 410 nm and 218 nm images, we produce spectral plots which graph intensity as a function of wavelength. This image is taken at cml180. Color Ratio Plot The Great Dark Spot The plot for the Great dark Spot looks no different than the rest of the plots on the north pole, but the standard deviation is smaller suggesting that the aerosol are more uniform in this region. CML180 North Pole Above are shown the spectral plots for the North Pole of Jupiter at CML 180. As the 410/218 color ratio increases and you move further North in the pole the intensity at 218 nm decreases. This tells us that as you get closer to the pole the concentration of aerosols increases. Acknowledgements : NSF REU CUNY/GISS Center for Global Climate Research, CUNY/NASA GSFC Heliophysics Education Consortium NASA NYC Research Initiative References Schmid, H.M. "Long Slit Spectroscopy of Jupiter and Saturn." ICARUS. (2011): Print. Caldwell, J., R. Halthore, G. Orton and J. Bergstralh, Infrared polar brightenings on Jupiter, IV, Spatial properties of methane emission, Icarus, 74, 331-339, 1988. Drossart, P., B. Bezard, S.Atreya, J. Lacy, E. Serabyn, A. Tokunaga, and T. Encrenaz, Enhanced acetylene emission near the north pole of Jupiter, Icarus, 66, 610-618, 1986 CML0 South Pole The graphs for the South Pole indicate the same feature as the North, that as the 410/218 color ratio increase and you get nearer to the pole the concentration of aerosols increases. Also the very large ratio value at 890 indicates the aerosols are very bright in the south pole. North Pole vs South Pole Above is shown a comparison of the yellow regions in the North/South poles at CML=0. The fact that this graph is not spectrally flat shows that there is a difference in composition between the North and the South. The higher absorption in the South at 218 nm (ratio greater than 1) along with the higher reflectivity at 890 nm (ratio less than 1), suggests a different composition for the South pole aerosol. Aerosol Polar CML Comparison Above we have compared different faces of Jupiter, CML= 180 and 0, to determine if the same aerosols are present all around the poles at different longitudes. Because the ratio between the intensities in the North pole all lie at about 1, it appears the aerosols do not vary in the North as the longitude changes. In the South however, the ratio strays from 1, suggesting that as we move around the longitudes at the South pole aerosol concentration and/or composition varies. This graph also shows that the aerosols are much thicker in the south at CML=0 than at CML=180. Summary/Conclusion Our analysis of Hubble space telescope data in September 1997 shows that the aerosols in the Northern and Southern poles are compositionally and concentrationally different. We have shown the aerosols in the North pole are constant with respect to longitude whereas the aerosols in the South pole are more concentrated at CML = 0. In both cases however, as you increase in latitude pole ward, the concentration of aerosols steadily increases. In the study of the Great Dark spot we have found that our results show no differences than any other region in the North pole, providing few conclusions about its cause and composition. In order to test our found conclusions regarding the differences between the North and South poles more studies need to be done. The cause is unknown, and it could be a result of Jupiter’s different seasons or differences in the auroras due to the magnetosphere.