[X] My Assistant

[Juramike]

Liquid Lakes confirmed on Titan!

Latest issue of Nature provides evidence that Ontario Lacus at Titan's South pole is definitely liquid.

Space.com article: http://www.space.com/scienceastronomy/080730-titan-lake.html

-Mike

[Juramike]

Brown et al. Nature 454 (2008), 607-610. "The identification of liquid ethane in Titan's Ontario Lacus." doi: 10.1038/nature07100.

(Pay for article: abstract here)

VIMS spectral analysis of lake, "beach" (annulus in text), and adjacent areas are consistent with ethane and higher order alkanes.
[Pretty hardcore spectral analysis. For those interested, here's a quick primer.].

-Mike

[Webscientist]

A large dark patch at the end of the summer season! I assume there has been a lot of evaporation in that area. A large cloud formation had been identified relatively close to this small sea or big lake. A fortiori, it results from the evaporation of this pool.
I wonder how is the rain: drizzle, heavy showers with lightning ? Maybe that in the north polar region, there is drizzle with so little sunlight coming in but in the south pole, there may be the opposite. I'm not a meteorologist but it seems to be a logical reasoning to me.

[volcanopele]

A large dark patch at the end of the summer season! I assume there has been a lot of evaporation in that area. A large cloud formation had been identified relatively close to this small sea or big lake. A fortiori, it results from the evaporation of this pool.

Could be, the lake could help to increase the humidity.

But I wouldn't drink the "lakes empty in summer, fill in winter" kool-aid just yet...

I wonder how is the rain: drizzle, heavy showers with lightning ? Maybe that in the north polar region, there is drizzle with so little sunlight coming in but in the south pole, there may be the opposite. I'm not a meteorologist but it seems to be a logical reasoning to me.

Drizzle in winter, heavy showers (no lightning) in summer. Summer polar climate on Titan is a lot like Arizona in the summer, bone dry with occasional downpours. Light showers don't happen very often (unless it is a small storm away from the main storm system) because the rain evaporates before it hits the ground. Heavy rain has a greater chance of hitting the ground.

We have to be careful with how we interpret data at the south pole. We have only gotten a few snapshots and we really need more to establish how the climate works down there. And VIMS has only one flyby with good images of Ontario. We will need more to establish if lake levels are rising or falling (if we can at all from VIMS data).

[Jason W Barnes]

I just wanted to call attention to the newly-released VIMS detection of Ethane within Titan's Ontario Lacus. Prior evidence for lakes, while compelling, was entirely circumstantial. The lakes look really dark in RADAR, and in ISS, and show lake-like morphologies. What we've found is the smoking gun that unambiguously identifies the lakes (well, this one at least) as being liquid, and composed at least partially of ethane. Presumably the ethane is in solution with liquid methane, but we can't identify methane since those lines are entirely saturated by looking through so much of it in the atmosphere.

Anyway, you can read either the press release or the paper in Nature. I've posted a copy of the paper on my website as well.

- VIMS Jason

[stevesliva]

It has been mentioned elsewhere (and there is a great post on http://planetary.org/blog ), but thank you for posting the paper!

[Jason W Barnes]

It has been mentioned elsewhere (and there is a great post on http://planetary.org/blog ), but thank you for posting the paper!

Ack -- just looked at the last page and didn't see Juramike's post from yesterday. My bad !

- VIMS Jason

[volcanopele]

Thanks for the post. This announcement illustrates the ideal strategy for using RADAR, ISS, and VIMS for complimentary science. ISS is great at providing an overview of a region, identifying targets of interest based on unique morphology and albedo at 938 nm. VIMS and RADAR can then adjust their pointing when they have prime coverage at closest approach to observe these unique features.

Now, we just need to look at the southern part of Kraken Mare

[volcanopele]

This should have its own thread anyway. Juramike's post and other posts after that moved to this topic.

[Jason W Barnes]

This announcement illustrates the ideal strategy for using RADAR, ISS, and VIMS for complimentary science. ISS is great at providing an overview of a region, identifying targets of interest based on unique morphology and albedo at 938 nm. VIMS and RADAR can then adjust their pointing when they have prime coverage at closest approach to observe these unique features.

I dunno if this is always the *ideal* strategy, but this particular observation was specifically targetted by VIMS because of the ISS observations of Ontario Lacus on Rev 9. So your strategy worked to perfection in this instance, at least, I would say!

- VIMS Jason

[belleraphon1]

Thanks Jason for that link to the Nature paper.....

This news article has some great VIMS images of the beach at Ontario Lacus.
http://www.dlr.de/en/desktopdefault.aspx/t.../86_read-13154/

Does VIMS have a site with updated image products?

I've walked the beaches of the Great Lakes (live near Lake Erie). Would love to walk this beach.

Craig

[Jason W Barnes]

This news article has some great VIMS images of the beach at Ontario Lacus.
http://www.dlr.de/en/desktopdefault.aspx/t.../86_read-13154/

Hey wow, that color one is one of mine, I think. Cool. Didn't realize that the European release was distinct.

Regarding the Beach, although we call it that, I don't think that it really is a beach. Geologists define a beach as "wave deposited sediments", which I'm not convinced these are. Standby for more on this; just submitted a paper to Icarus last week about what it and the outer, bright ring might be and what that means.

- VIMS Jason

[belleraphon1]

Jason..

Thanks for the clarification regarding the 'beach'. Look forward to the paper in Icarus, if I can just find an open source to access it.

Still wanna walk it...

Keep us informed.....

Craig

[rlorenz]

Regarding the Beach, although we call it that, I don't think that it really is a beach. Geologists define a beach as "wave deposited sediments", which I'm not convinced these are. Standby for more on this; just submitted a paper to Icarus last week about what it and the outer, bright ring might be and what that means.

Or better yet, stand by for T49 when we will get altimetry on it. My guess is the whole thing
('beach' and all) will be 10^-3 or lower slope (i.e. a tidal flat) but we will see a radiometric
transition where the present 'waterline' is (presumably the residual ethane - with some amount
of methane having seasonally evaporated)

Of course, RADAR data is merely 'circumstantial' per your earlier post, maybe that isnt of
interest ....

[Juramike]

"Hey, you got SAR RADAR data in my VIMS?"
"And you got VIMS in my RADAR!"
"Oh wow! Tastes great!"
[Voiceover] "Two great flavors in one..."
(Shameless apologies to Nestle's Peanut Butter Crunch)

Unfortunately, to really nail things down, RADAR + VIMS + "something else" is probably going to be necessary to fully tease out the composition of the lakes and lakeshore.

"something else" = :

in situ GC (maybe not sufficient)
in situ GC-MS
and the Queen MacDaddy of them all, in situ stopped flow injection HPLC - 2D NMR (a 1H-13C heteronuclear correlation experiment)
lander with full suite of analytical experiments above
sample return (for the trace complex organics)

There will need to be something to figure out the mechanical properties (inferred by volume scattering) of the lakeshore stuff and some type of in situ chemical separation (the GC part) and some type of separated component analytical detection. The really hardcore stuff will be required for any funky organic species. (Unless there is a massive library of Titan-like compounds with which to try to compare analytical fingerprints discrete structures).

I think of Titan as a massive natural products isolation and determination exercise (like where they grind up some rare deep sea sponge and try to extract and determine all the bizarre molecular structures). Just figuring out one of the complex structures made by critters (palytoxin is one of the more complex ones) is usually the subject of one or more papers.

"Tholins" as a catch-all phrase still seems way too generic: it would be like referring to enzyme structures as "proteins" or other complex structures as "alkaloids".
"Hydrocarbons" or "alkanes" is equally unsatisfying. Which ones? What's the proportion?

-Mike