Leicester scientist studies the weather - on Neptune

Posted by ap507 at May 15, 2015 10:43 AM |
Forecast is bright for physicist as NASA mission sends over 100,000 images

Issued by the University of Leicester Press Office on 15 May

Video illustrating 70 days of uninterrupted observation of Neptune and two of its moons available from: https://www.dropbox.com/s/eyu895hvev8stom/Neptune_TheMovie.mp4?dl=0

A University of Leicester space scientist has played a stellar role in a new study of Neptune.

Dr Sarah Casewell, of the Department of Physics and Astronomy, is the sole Leicester scientist in a project to study Neptune’s weather.

NASA's Kepler spacecraft, operating as the K2 mission, has imaged Neptune and two of its moons, Triton and Nereid. The movie illustrates 70 days of uninterrupted observation making this one of the longest continuous observations of a solar system object ever obtained.

While NASA’s Kepler spacecraft is known for its discoveries of planets around other stars, an international team of astronomers, including Dr Casewell, plans to use these data to track Neptune’s weather and probe the planet’s internal structure by studying subtle brightness fluctuations that can only be observed with K2.

Dr Casewell said: “I have spectacular images of Neptune taken in January 2015 from the Keck telescope in which we show the weather patterns on Neptune as it rotates. We will ultimately be able to see what changes the weather has on the brightness of Neptune as seen from Kepler, and to compare these patterns with data from other systems, such as brown dwarfs, where we can’t resolve the disk of the planet and see features as we can with Neptune.

“Having access to the Kepler K2 data is a fantastic opportunity to study Neptune, and especially its weather in detail, as there are no space missions planned and the last mission to visit Neptune was Voyager 2 in 1989.”

Neptune appears on day 15 of the video but does not travel alone in the video. The small faint object closely orbiting is its large moon Triton, which circles Neptune every 5.8 days. Appearing at day 24, keen-eyed observers can also spot the tiny moon Nereid in its slow 360-day orbit around the planet. A few quick-moving asteroids also make cameo appearances in the movie, showing up as streaks across the K2 field of view. The red dots are stars outside the solar system.

Neptune's atmosphere reflects sunlight creating a bright appearance. The reflected light floods a number of pixels of the spacecraft's on board camera, producing the bright spikes extending above and below the planet. The stitched together images are coloured red to represent the wavelength response of the spacecraft's camera. In reality, Neptune is deep blue in colour and its moons and the speeding asteroids are light grey while the background stars appear white from a distance.

Planets orbit the sun at different speeds. Inner planets like Earth orbit more quickly than outer planets like Neptune. In the movie, Neptune’s apparent motion relative to the stationary stars is mostly due to the circular 372-day orbit of the Kepler spacecraft around the sun. If you move your head back and forth you will notice that objects close to you will also appear to move back and forth relative to objects far away.  The same concept is producing the apparent motion of Neptune.


The movie is based on 101,580 images taken from December 2014 through January 2015 during K2's Campaign 3, reveals the perpetual clockwork of our solar system. The 70-day timespan is compressed into 34 seconds with the number of days noted in the top right corner.


NASA release:



For interviews contact Dr Sarah Casewell on:

Email: slc25@le.ac.uk
Phone:+44(0)116 2523577
Web: www2.le.ac.uk/departments/physics/people/sarahcasewell

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