Dawn approaches Ceres, From opnav images to first orbit Options

[JohnVV]

-- edited see other thread
http://www.unmannedspaceflight.com/index.p...mp;#entry219452

[MichaelJWP]

Anyone know when the latest images will be released? i.e. OPNAV 6?
Or are they waiting until after OPNAV 7 before showing anything more?

[katodomo]

EGU2015 Press Conference 2: "New results from NASA's Dawn spacecraft at Ceres" will start in 3 minutes.

http://client.cntv.at/egu2015/PC2

[Habukaz]

^ Interesting. I didn't watch all of it, but I extracted these pair of interesting images from VIR that show how one bright spot (spot 1) behaves differently from the brightest spot on Ceres (spot 5):





namely that the brightest spot disappears in the thermal data while the other one don't. The leftmost image for spot 1 is true colour (not specified for spot 5), while the rightmost is thermal data (for both).

Anyone know when the latest images will be released? i.e. OPNAV 6?
Or are they waiting until after OPNAV 7 before showing anything more?

I haven't seen any specific information having been provided beyond this tweet:

Not yet, @AndrewLabmonkey, data today, images sometime next week, just a sliver of #Ceres.. Moving to the #sunnyside!

My own personal guess would be tomorrow or Wednesday for OpNav 6 and Friday, Monday or Tuesday for OpNav 7.

[katodomo]

To summarize from the above stream, since i don't think it'll be available for later watching:

- Russell (Dawn mission PI) mostly laid out how Dawn was entering orbit, and how it will do RC3, timeline for Survey Orbit, HAMO, LAMO etc.
- Hoffmann (FC team Science/Operations) did some topographic comparison to Vesta and other bodies, and had a false color global map intended to show off albedo differentiation i think
- Tosi (VIR team member) presented VIR and the above two images pretty much.

- I think the three mostly recapped their slightly longer presentations from earlier today.
- Q&A session afterwards had questions regarding the spots (and, to Hoffmann, regarding statements from earlier Dawn presentations today) from Jonathan Amos, an AFP reporter who I think didn't give her name and two or so through the stream's chat function. Mostly answered with "not enough resolution yet, wait till RC3 is wrapped up".
- Press conference wrapped up after about 45 minutes due to lack of further questions.

[dmg]

I am able to still watch the Press Conference now (06:33 Pacific Daylight Time = 13:33 UTC) -- starting at the beginning --- at http://client.cntv.at/egu2015/PC2

[Habukaz]

I see the VIR images and the colour map have been released via the Photojournal now: http://photojournal.jpl.nasa.gov/keywords/dp

[katodomo]

I am able to still watch the Press Conference now (06:33 Pacific Daylight Time = 13:33 UTC) -- starting at the beginning --- at http://client.cntv.at/egu2015/PC2

Yeah, they have now switched over to a regular stream - the stream during the conference itself used different software, and didn't allow you to scroll back or do any settings. They shut that one off at source the moment the press conference was declared over, with the streaming software immediately getting a 404 Error.

Pleasant surprise, given that the EGU website never said anything about streaming beyond live.

[mcgyver]

Hotspot not so hot?
http://phys.org/news/2015-04-dwarf-planet-...awns-giant.html


The "most famous" bright spot (officially named "spot 5") is represented in lower three images: it totally disappears in thermal wavelength.

[Paolo]

"spot number 5" is not an official name. it's just a "placeholder" name used by the scientific team. Don't get used to it.

[katodomo]

Makes one wonder which ones Spots 2 to 4 are, and whether "Spot" exclusively applies to the bright spots (or more generally to other albedo features too). And whether the one in the crater south of the equator is Spot 6.

[Phil Stooke]

If you look back through the Dawn threads you will find a map made from Hubble images with the spots numbered.

Phil

[john_s]

The "most famous" bright spot (officially named "spot 5") is represented in lower three images: it totally disappears in thermal wavelength.

My guess for the reason for this is simply that Spot 5 is very small. It's probably cold, and thus probably emits little thermal radiation at VIR wavelengths, but it occupies such small fraction of a VIR pixel that the resulting reduced radiation from that pixel is lost in the noise. The other spot is much bigger so its signature is obvious, even though it's probably not as cold at Spot 5.

John

[Habukaz]

I think it might be interesting to note, though, that the 'dark' thermal signature of spot 1 is much bigger and more obvious than its signature in the visual spectrum; yet we see absolutely no signature of spot 5. Actual calculations could perhaps show that this is insignificant since even the "extended" signature could be too small to be detectable; but this stood out to me.

[dudley]

I'm not altogether certain that the bright spot in area 1 is much larger than that in area 5. The former is rather diffuse. Its hard to say exactly where it ends and the surroundings begin. In the visual range, it seems, at most, about half again as large as the area 5 spot. At the minimum, it may even be smaller than area 5.
In any case, the area 1 spot is dimmer, and the surroundings appear brighter than the area 5 spot. This should have minimized the temperature differences in area 1, it seems.
Given these considerations, it appears more likely that the area 5 bright spot should have shown some temperature difference in the thermal range.