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Laboratory for Atmospheric and Space Physics

3: Observations and Results

August 1, 2016

By Lucy Todd, Summer 2016.

Despite the unlikelihood of receiving radio emissions from Jupiter during the months in which is it not observation season, I was still determined to set up the telescope on the slim possibility that I could detect anything at all. I also thought that it would be valuable to document the experimental process for the benefit of others at LASP who may wish to continue this project when the next observation season begins.

As noted in my previous blog post, interference from the Sun during the day meant that I had to do my observations at night if I hoped to detect Jupiter emission, so I recorded my data primarily between 9pm and 4am.

Predicting Radio Storms

Before going out to take readings, it is best to check what times it is most likely that Jupiter radio storms will occur. This can be done using Radio-Jupiter Pro 3, the license for which is provided with the Radio JOVE kit and the software freely available to download from the Radio JOVE website. When you input details such as you observing latitude in the program, Radio-Jupiter Pro 3 can predict when these storms are likely to occur and display this information graphically (see image below).

CML PLot

An example of a CML Io Phase Plot produced by Radio-Jupiter Pro 3. This sows a where Jupiter is within the plane defined by central meridian longitude (CML) and Io Phase (where Io is in its orbit). The white line shows Jupiter’s track for times when it is above the horizon and the blue for periods when it is below the horizon. The dotted line represents the next day.

Using this plot therefore, observation times can be decided based on predicted storms.

Testing the Telescope

Before taking any observations, I made sure to test the antenna and receiver together first to ensure that everything worked correctly. I did this by connecting the antenna to the receiver and the receiver into the PC via an aux to aux cable. I could then use Radio Skypipe software (also provided online) to record any incoming radio emissions both in a chart and in audio form. I could also listen to the signal via headphones into the second audio output on the receiver. When the antenna was connected, I observed a significant increase in background noise as the manual described, which was a good sign that the system was working correctly.

Once connected, the antenna was able to pick up the galactic background radiation (produced by relativistic electrons spiraling on the galactic magnetic field). An example of what this background sounds like can be heard on the Radio JOVE website.

An example chart showing the constant galactic background radiation.

An example chart showing the constant galactic background radiation.

Desired Results

The type of emissions that I was hoping to hear were Decameter waves and could come in two forms: L- and S-bursts. These two distinct bursts can be distinguished from each other by how they sound. L-bursts sound like ocean waves breaking, and S-bursts like popping corn (listen to audio samples below).

lburst_chart

An example of an L-burst emission chart taken from the Radio JOVE website and its associated audio below.

 

 

 

sburst_chart

An example of an S-burst emission chart taken from the Radio JOVE website and its associated audio below

 

 

Observations Made

As predicted, I was unable to hear any Jupiter radio emissions over the course of four nights of observations. Despite this however, I feel the observations were successful in demonstrating that the telescope functions correctly, as I was able to detect the galactic background radiation as well as detect nearby radio stations when tuning across the receiver with the tuning dial.

Example Data

Example Radio JOVE output chart showing constant Galactic Background signals (generated by relativistic electrons spiralling in the galactic magnetic field) and peaks indicating static caused by the interference of other radio emissions from other sources. This chart obtained during observations on 07/18/16.

Even though I was unable to detect emissions this time, further observations can now be made by others at LASP with the telescope over the duration of the next few Jupiter Observing Seasons. Additionally, over the course of the Juno mission, 37 close approaches to Jupiter are planned to occur. It is likely that the next Jupiter Observing Seasons will overlap with these close approaches. In this case, it will be of interest if future observers at LASP to gather data from Radio JOVE at the same time as Juno and compare observations to see if the emission patterns the telescope is receiving is consistent with the data Juno gathers.

Acknowledgements

This project was funded by the Juno mission grant. Help with the construction of the telescope was provided by the researchers, graduates, undergraduates and associates of the LASP Magnetospheres of the Outer Planets Group listed below: Evan Sidrow, Kaleb Bodisch, Logan Dougherty, Eddie Nerney, Frederick Thaye, Drake and Emily Ranquist, David Malaspina and Vaughn Hoxie.

The Radio Jove 1.1 Radio Telescope Kit was sold and distributed by the Radio JOVE Project Inc. and used in conjunction with Radio-SkyPipe II software and Radio-Jupiter Pro 3 software.

 

Abstract, Poster and presentation describing by work on this project can be found here:

Abstract | Poster | Presentation Slides

I also want to give a special thank you to my mentor Fran Bagenal for all her help, encouragement and support with this project, as well as introducing me to the REU program at LASP.

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