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Stuff from the DPS-EPSC conference, day 2
Oct. 4th, 2011 03:48 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
steorraAgain, first more information presented by people who know more than I do:
Emily Lakdawalla's post on Day 2 includes:
- a bit about recent flyby data from the comets Hartley 2 and Tempel 1.
- size data on Makemake based on an occultation; also, results from infrared data indicate that Makemake has a surface with mixed really really bright and really really dark patches
- weird results from an occultation about Quaoar's size - it 'looked like someone had taken a bite out of it'
- a few things about Titan
Three official press releases of the day:
One on a discovery made using the Kepler spacecraft on the discovery of a star with three identified planets. The smallest has a mass of 6.9 times that of Earth, while the larger two have mass of 16-17 times that of Earth (i.e., about Neptune's mass). All three are much closer to their star than Mercury is to the sun.
A second on oddities of comet Hartley 2, including that it may be two former comets that got stuck together.
Third, and most exciting to me, is one about a global false-colour map of Titan using data from Cassini's Visual and Infrared Mapping Spectrometer (VIMS). This is really hard to do because of Titan's atmosphere, which is opaque to most wavelengths of light, and even with the wavelengths that can penetrate it, there are still atmospheric effects, e.g. from clouds and mist.
And now for what I've managed to extract from Twitter. As with last time, I could have introduced all kinds of distortions, so take all this with a good dose of grains of salt. There was also plenty more interesting stuff that I saw but couldn't understand/contextualize well enough to put it into a post. (Lots of that was about Titan.)
Vesta
Vesta's pole star is Deneb.
Titan
Titan seems to have seasonal rain in normally dry equatorial deserts.
There's a case made for Titan having dust storms.
Does Titan have ice volcanoes? Maybe, maybe not. Lots of things that looked like volcanoes at first seem not to be on closer inspection, but there's one good candidate: Sotra Facula.
Kuiper Belt Objects
Results from Eris occulting a star were presented, but couldn't be reported on Twitter due to an embargo :-( . They'll be published in Nature on Oct. 26th.
Makemake occulted a star with of magnitude V=18.2 on April 23, 2011. They observed the occultation with 7 telescopes in 5 locations, and found a drop in magnitude of 0.4. They were able to calculate Makemake's albedo as about 0.71, which is greater than Pluto's, and is consistent with the value of 0.81 derived from measurements the infrared telescopes Spitzer and Herschel. They calculate Makemake's size based on the occultation as about 1610 +22/-180 km x 1444+/-9 km. Whether or not the occultation data indicates an atmosphere is still being worked out.
Quaoar occulted a star too, and they observed it from at least 5 sites. Quaoar has is less reflective than was previously thought; this means that it's also larger and less dense. Its diameter is now estimated as 1045-1095 km, and density at 1.95-2.75 grams per cubic centimeter. It might have a methane atmosphere with a pressure of 0.1 ubar [I think ubar is an alternate abbreviation for µbar = microbar, but I'm not certain] at a temperature of 45K.
Extrasolar planets
The Kepler spacecraft's major measurements come from planets transiting their stars, but the measurements are also affected by how the planet and star distort each other tidally. Using these tidal distortions, it's possible figure out the mass ratio between the planet and the star just from observing transits. (Neat! It always amazes me how much information astronomers can squeeze out of a seemingly tiny bit of data.)
Upcoming missions
The European Space Agency's Solar Orbiter mission has been approved. It will orbit the sun in a highly inclined orbit inward of Mercury's orbit, and is expected to launch in 2017.
Other stuff
WISE shows 4 things that might potentially be very low mass brown dwarfs orbiting the sun. But they might also be extragalactic sources of radiation. (That's a big difference!)
Sources of tweets that I've used to compile this (again, I hope I haven't left anyone out):
![[twitter.com profile]](https://p.dreamwidth.org/e0caa790ec10/-/twitter.com/favicon.ico)
DrFunkySpoon
GovertTweets
AllPlanets
elakdawalla
PlanetDr
spacemandave
Emily Lakdawalla's post on Day 2 includes:
- a bit about recent flyby data from the comets Hartley 2 and Tempel 1.
- size data on Makemake based on an occultation; also, results from infrared data indicate that Makemake has a surface with mixed really really bright and really really dark patches
- weird results from an occultation about Quaoar's size - it 'looked like someone had taken a bite out of it'
- a few things about Titan
Three official press releases of the day:
One on a discovery made using the Kepler spacecraft on the discovery of a star with three identified planets. The smallest has a mass of 6.9 times that of Earth, while the larger two have mass of 16-17 times that of Earth (i.e., about Neptune's mass). All three are much closer to their star than Mercury is to the sun.
A second on oddities of comet Hartley 2, including that it may be two former comets that got stuck together.
Third, and most exciting to me, is one about a global false-colour map of Titan using data from Cassini's Visual and Infrared Mapping Spectrometer (VIMS). This is really hard to do because of Titan's atmosphere, which is opaque to most wavelengths of light, and even with the wavelengths that can penetrate it, there are still atmospheric effects, e.g. from clouds and mist.
And now for what I've managed to extract from Twitter. As with last time, I could have introduced all kinds of distortions, so take all this with a good dose of grains of salt. There was also plenty more interesting stuff that I saw but couldn't understand/contextualize well enough to put it into a post. (Lots of that was about Titan.)
Vesta
Vesta's pole star is Deneb.
Titan
Titan seems to have seasonal rain in normally dry equatorial deserts.
There's a case made for Titan having dust storms.
Does Titan have ice volcanoes? Maybe, maybe not. Lots of things that looked like volcanoes at first seem not to be on closer inspection, but there's one good candidate: Sotra Facula.
Kuiper Belt Objects
Results from Eris occulting a star were presented, but couldn't be reported on Twitter due to an embargo :-( . They'll be published in Nature on Oct. 26th.
Makemake occulted a star with of magnitude V=18.2 on April 23, 2011. They observed the occultation with 7 telescopes in 5 locations, and found a drop in magnitude of 0.4. They were able to calculate Makemake's albedo as about 0.71, which is greater than Pluto's, and is consistent with the value of 0.81 derived from measurements the infrared telescopes Spitzer and Herschel. They calculate Makemake's size based on the occultation as about 1610 +22/-180 km x 1444+/-9 km. Whether or not the occultation data indicates an atmosphere is still being worked out.
Quaoar occulted a star too, and they observed it from at least 5 sites. Quaoar has is less reflective than was previously thought; this means that it's also larger and less dense. Its diameter is now estimated as 1045-1095 km, and density at 1.95-2.75 grams per cubic centimeter. It might have a methane atmosphere with a pressure of 0.1 ubar [I think ubar is an alternate abbreviation for µbar = microbar, but I'm not certain] at a temperature of 45K.
Extrasolar planets
The Kepler spacecraft's major measurements come from planets transiting their stars, but the measurements are also affected by how the planet and star distort each other tidally. Using these tidal distortions, it's possible figure out the mass ratio between the planet and the star just from observing transits. (Neat! It always amazes me how much information astronomers can squeeze out of a seemingly tiny bit of data.)
Upcoming missions
The European Space Agency's Solar Orbiter mission has been approved. It will orbit the sun in a highly inclined orbit inward of Mercury's orbit, and is expected to launch in 2017.
Other stuff
WISE shows 4 things that might potentially be very low mass brown dwarfs orbiting the sun. But they might also be extragalactic sources of radiation. (That's a big difference!)
Sources of tweets that I've used to compile this (again, I hope I haven't left anyone out):
