Looking for Waves on Titan’s Seas

Titan (T-91) Flyby Credit: NASA/JPL-Caltech
Titan (T-91) Flyby
Credit: NASA/JPL-Caltech

Cassini’s next flyby is another encounter with Titan! If you want to know more about flybys in general, check out this link. And feel free to follow along with the latest information and images from the flyby on my Facebook event page: Titan (T-91) Flyby

Quick Facts:

  • Name Titan (T-91) Flyby
  • Date May 23, 2013 [SCET]
  • Altitude 970 kilometers (603 miles)
  • Speed 13,000 mph (5.8 km/sec)
  • Goal To look for waves on Titan’s northern sea, Ligeia Mare

What will we be able to see?

Cassini’s camera system, also known as the Imaging Science Subsystem (ISS) instrument onboard the Cassini spacecraft, will image a number of different places on Titan this flyby. ISS will observe Titan’s north polar lakes. The cameras will be centered in an area containing Bolsena Lacus  and Neagh Lacus. These lakes, along with Jingpo Lacus, are the largest bodies of liquid methane/ethane outside of the three seas (Kraken Mare, Ligeia Mare, and Punga Mare) in Titan’s north polar region. (Click the image below to see more of Titan’s north polar lakes and seas.)

Close up of Titan's North Polar Lakes and Seas Credit: NASA/JPL/USGS
Close up of Titan’s North Polar Lakes and Seas
Credit: NASA/JPL/USGS

ISS will image Titan’s mid-latitudes south of Belet, including as far north as Concordia Regio. Belet, also known as Titan’s “sand sea” is made of vast hydrocarbon dunes. Belet’s dunes have even been compared to Earth’s Oman dunes in Yemen and Saudi Arabia. (Read more about that here.)

Belet Below the Haze Credit: NASA/JPL/SSI/ edited by Val Klavans
Belet Below the Haze
Credit: NASA/JPL/SSI/ edited by Val Klavans

ISS will also make a final observation of the south polar vortex, before the Sun sets in the south. If the vortex is illuminated during the observation, this will be the highest resolution imaging of the south polar vortex from ISS!

Titan's South Polar Vortex Credit: NASA/JPL/SSI/ composite & compilation by Val Klavans
Titan’s South Polar Vortex
Credit: NASA/JPL/SSI/ composite & compilation by Val Klavans

What science will be coming out of this flyby?

The overall goal of this flyby is to find out if there are waves on Titan’s seas. Cassini’s RADAR instrument will acquire altimetry over Ligeia Mare in order to accomplish this. Sea surface roughness of several millimeters will be able to be measured, giving the most sensitive test for surface waves resulting from winds, drainage from rivers flowing into Ligeia Mare, or tides. This altimetry data could show whether the surface of Ligeia is thick like molasses or as thin as liquid water on Earth.

Ligeia Mare, Credit: NASA/JPL-Caltech/USGS/ edited by Val Klavans
Ligeia Mare,
Credit: NASA/JPL-Caltech/USGS/ edited by Val Klavans

In addition, RADAR will acquire high-altitude Synthetic Aperture Radar (SAR) imaging of the southern and eastern portion of Kraken Mare (Titan’s largest methane/ethane sea). RADAR will also make SAR swaths across northern Belet, southern and western Adiri, and Concordia Regio. Concordia Regio and Adiri were affected by the “Arrow Storm” in 2010 and resulted in localized flooding in Concordia Regio. These altimetry swaths can be compared to the pattern of brightening following the storm to see if it matches with the idea that it was due to rain runoff that flowed into local basins and river flood plains.

Titan's Arrow-Shaped Storm Credit: NASA/JPL/SSI
Titan’s “Arrow Storm”
Credit: NASA/JPL/SSI

Cassini’s Composite Infrared Spectrometer (CIRS) instrument will also be checking on Titan this flyby. CIRS will make a spectral scan of Titan’s night side and sunlit crescent, will scan across Titan in order to map temperatures in its stratosphere, and will scan across Titan’s limb to measure aerosol and chemical abundances at different altitudes above Titan’s surface.

Sources

Want to know even more about this flyby? Check out Cassini Imaging Central Laboratory for Operations’ (CICLOPS) website with information on Cassini’s activities every day: Rev190: May 16 – May 26 ’13 and a quick overview of this flyby from Cassini’s main website: Titan Flyby (T-91): Looking for Waves. (All of my information from this post, unless otherwise specified, comes from these great sources.)

Images

Now that all of the images have come in from the flyby, let’s take a look!

As Cassini closed in on Titan, the ISS captured a set of images of its hazy crescent. The image below is an approximate true color image of Titan. ISS took the images that make up this composite while Cassini’s Composite Infrared Spectrometer (CIRS) instrument monitored Titan’s stratosphere.

Titan's 92nd Flyby, Credit: NASA/JPL/SSI/ composite by Val Klavans
Titan’s 92nd Flyby,
Credit: NASA/JPL/SSI/ composite by Val Klavans

If you read “Titan’s 92nd Flyby” above and thought it was the 91st flyby, you’re not going crazy. Titan (T-91) Flyby really is Titan’s 92nd flyby. Read more about this here.

ISS also captured Titan’s south polar cloud. Below is the cloud seen in false color. The images that were used to make this composite image were taken in red, methane band (where methane is strongly absorbing), and blue filters. This is Cassini’s final mission observation of the cloud, first observed in March 2012.

Titan's South Polar Cloud in False Color Credit: NASA / JPL / SSI / composite by Val Klavans
Titan’s South Polar Cloud in False Color
Credit: NASA / JPL / SSI / composite by Val Klavans

ISS also imaged below Titan’s haze to see its surface. In the image below, the dark areas are regions of hydrocarbon dunes. At the very bottom, the south polar vortex is visible. ISS used its continuum band filter (where methane is more transparent) to image below Titan’s haze.

Looking to the surface Credit: NASA/JPL/SSI/ processed by Val Klavans
Looking to the surface
Credit: NASA/JPL/SSI/ processed by Val Klavans

If you want to see more images from the flyby, check out the event page I made for the flyby on Facebook.

***

Well that wraps up coverage of the Titan (T-91) Flyby! Cassini’s next flyby: Titan (T-92) Flyby occurs on July 10 so get excited!

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