Full Version: Kepler Mission
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One thing that exacerbates the problem is that the field rotates 90 degrees every three months, so even if the problem is contained within a small number of sensors (3 max) then that still means that up to 12 out of the 42 segments within the field will be affected. There does seem to be some confusion over how the software processing on board Kepler works -- some say that the processing integrates all the data across all sensors and amplifiers, and others are not so sure. I think we're going to have to wait for a detailed explanation from the Kepler team themselves, who are still claiming that it's not that bad a problem.
If you look at this picture:
http://en.wikipedia.org/wiki/File:329161ma...llFFIHot300.png
you can clearly see 42 segments in the FOV. I would imagine there are two "channels" per segment, for a total of 84 channels.
If I'm reading Borucki's update correctly, the data from the 3 noisy channels won't be mixed together with the other 81 channels until after extrasolar Earths have been searched for within the 81 channels. Only after that will the 3 noisy channels be mixed in.
I'm not sure what exactly entails "mixing" nor do I know why it's beneficial. Any of us could make some guesses I suppose.
http://en.wikipedia.org/wiki/File:329161ma...llFFIHot300.png
you can clearly see 42 segments in the FOV. I would imagine there are two "channels" per segment, for a total of 84 channels.
If I'm reading Borucki's update correctly, the data from the 3 noisy channels won't be mixed together with the other 81 channels until after extrasolar Earths have been searched for within the 81 channels. Only after that will the 3 noisy channels be mixed in.
I'm not sure what exactly entails "mixing" nor do I know why it's beneficial. Any of us could make some guesses I suppose.
Good news:
http://www.newscientist.com/article/dn1809...ien-earths.html
It's worth reading the whole article (I would quote more but that would be against the rules).
QUOTE
Three of these channels are plagued by electronic noise that makes stars in their field of view appear to flicker – "like it's changing its brightness at a rapid rate", says Kepler chief scientist William Borucki of NASA's Ames Research Center in Moffett Field, California.
The tiny brightness dips from a transiting Earth-size planet could be lost amid these fluctuations. But since the problem affects only a few of the 84 channels, it is not expected to hide all Earth-size planets, Borucki says.
"People have found a pimple here and they are trying to make it into a mountain," he told New Scientist. "A lot of the planets will show up regardless."
...
The team is developing software to automatically remove the noise from data after it is sent down to Earth, but rigorous testing means it will not be ready until 2011.
The tiny brightness dips from a transiting Earth-size planet could be lost amid these fluctuations. But since the problem affects only a few of the 84 channels, it is not expected to hide all Earth-size planets, Borucki says.
"People have found a pimple here and they are trying to make it into a mountain," he told New Scientist. "A lot of the planets will show up regardless."
...
The team is developing software to automatically remove the noise from data after it is sent down to Earth, but rigorous testing means it will not be ready until 2011.
http://www.newscientist.com/article/dn1809...ien-earths.html
It's worth reading the whole article (I would quote more but that would be against the rules).
I think there is a mistake in the article, it says Earth's twin would have a one year orbit, but from what I see it could be longer or shorter depending on the heat of the star and/or distance.
Is my thinking correct ?
Also I find it interesting that they say the stars are not as variable as they orginally thought.
Is my thinking correct ?
Also I find it interesting that they say the stars are not as variable as they orginally thought.
QUOTE (MahFL @ Nov 4 2009, 10:52 AM) 
it says Earth's twin would have a one year orbit, but from what I see it could be longer or shorter depending on the heat of the star and/or distance.
It depends on how "Earth's twin" is defined. You could be correct or the article could be correct.
As an aside, most scientists, IMHO, would have the definition include liquid water in addition to temperature, size, and mass.
I've never seen an official definition. Anybody know if there is one?
I believe they deem an Earth-twin to be an Earth-like planet orbiting a Sun-like star in the habitable zone -- which necessarily means that the planet's orbit will take about a year, give or take a month or two.
They are hoping to find Earth-like planets around other stars -- notably cooler stars than our Sun, like red dwarfs, where the habitable zone is closer in. It is the detection of these planets, with orbits of perhaps only 3 to 6 months that will be most affected by the delay in data processing, since if there were no glitchy amplifiers, they should be detectable before the software fix is available in 2011.
But if all the transits of such planets are caught by the detectors with clean amplifiers, then there is still a chance that they will be able to announce some discoveries of this type next year, but remember that the spacecraft is rotated 90 degrees every three months, increasing the chances that at least one of the three required transits will by masked by a glitchy amplifier, and thus detection will be delayed until the fix is available.
They are hoping to find Earth-like planets around other stars -- notably cooler stars than our Sun, like red dwarfs, where the habitable zone is closer in. It is the detection of these planets, with orbits of perhaps only 3 to 6 months that will be most affected by the delay in data processing, since if there were no glitchy amplifiers, they should be detectable before the software fix is available in 2011.
But if all the transits of such planets are caught by the detectors with clean amplifiers, then there is still a chance that they will be able to announce some discoveries of this type next year, but remember that the spacecraft is rotated 90 degrees every three months, increasing the chances that at least one of the three required transits will by masked by a glitchy amplifier, and thus detection will be delayed until the fix is available.
The Kepler press kit doesn't mention the word "twin" but it's clear that they are distinguishing between Earth-like (or Earth-sized) planets orbiting M class stars (red dwarfs) and those orbiting Sun-like stars:
It's the December 2010 announcements that will be impacted most by the faulty amplifiers, but assuming they can successfully filter out the signal noise introduced by those amps, detection of the affected transits will only be delayed, not lost.
Hey, I just realized that if all goes well they could be announcing the first "Earth-twin" in my home town in Dec 2012. I wonder if they would notice a non-astronomer sneaking in at the back?
QUOTE
Approximately in December 2010, scientists expect to announce any discoveries they have made in the
first year. This will be the first possible announcement of Earth-size planets in the habitable zones of
M-type stars, which are stars smaller and cooler than the sun.
Discovery of Earth-size planets in Earth-like orbits requires nearly the full lifetime of the 3.5 year mission,
although in some cases three transits are seen in just a little more than two years. Other results that
require the full 3.5 years of data are: Planets as small as Mars in short period orbits, which utilizes the
addition of dozens or more transits to be detectable; and the detection of giant-inner planets that do not
transit the star, but do periodically modulate the apparent brightness due to reflected light from the planet.
Approximately in December 2011, scientists are expected to announce any discoveries made during the
first two years of the mission. The announcement will be made at NASA Headquarters and later at the
January 2012 American Astronomical Society (AAS) meeting held in Seattle, Wa., as well as at NASA’s
Ames Research Center. This will be the first possible announcement of Earth-size planets in the habitable
zones of K-type stars.
Around December 2012, scientists are expected to announce any discoveries made during the first
three years of the mission. The announcement will be made at NASA Headquarters and later at the AAS
meeting held in Austin, Texas, as well as at NASA’s Ames Research Center. This is the first possible
announcement of Earth-size planets in the habitable zones of solar-like or G stars.
first year. This will be the first possible announcement of Earth-size planets in the habitable zones of
M-type stars, which are stars smaller and cooler than the sun.
Discovery of Earth-size planets in Earth-like orbits requires nearly the full lifetime of the 3.5 year mission,
although in some cases three transits are seen in just a little more than two years. Other results that
require the full 3.5 years of data are: Planets as small as Mars in short period orbits, which utilizes the
addition of dozens or more transits to be detectable; and the detection of giant-inner planets that do not
transit the star, but do periodically modulate the apparent brightness due to reflected light from the planet.
Approximately in December 2011, scientists are expected to announce any discoveries made during the
first two years of the mission. The announcement will be made at NASA Headquarters and later at the
January 2012 American Astronomical Society (AAS) meeting held in Seattle, Wa., as well as at NASA’s
Ames Research Center. This will be the first possible announcement of Earth-size planets in the habitable
zones of K-type stars.
Around December 2012, scientists are expected to announce any discoveries made during the first
three years of the mission. The announcement will be made at NASA Headquarters and later at the AAS
meeting held in Austin, Texas, as well as at NASA’s Ames Research Center. This is the first possible
announcement of Earth-size planets in the habitable zones of solar-like or G stars.
It's the December 2010 announcements that will be impacted most by the faulty amplifiers, but assuming they can successfully filter out the signal noise introduced by those amps, detection of the affected transits will only be delayed, not lost.
Hey, I just realized that if all goes well they could be announcing the first "Earth-twin" in my home town in Dec 2012. I wonder if they would notice a non-astronomer sneaking in at the back?
QUOTE (tacitus @ Nov 4 2009, 11:47 AM)
Hey, I just realized that if all goes well they could be announcing the first "Earth-twin" in my home town in Dec 2012.
Nice!
Austin is my home city and Mountain View (Ames Research Center) is my city of residence.
I think your avatar kind of gave that away
http://archive.stsci.edu/mast_news.php?out...sc=t&id=342
QUOTE
Kepler Dropped Targets now Public
11/04/09
Roughly 7,500 Kepler Light curve files are now available to the public for download. To see the available files, go to the Kepler Data Search form , enter " < 2010" in the box labelled "Release Date", and click the "Search" button.
Please note the Data Use Policy comments regarding the use and interpretation of the current Kepler data.
11/04/09
Roughly 7,500 Kepler Light curve files are now available to the public for download. To see the available files, go to the Kepler Data Search form , enter " < 2010" in the box labelled "Release Date", and click the "Search" button.
Please note the Data Use Policy comments regarding the use and interpretation of the current Kepler data.
I searched for a scientific guide on what qualifies as Earth-like or Earth-twin. Didn't find anything. I performed some research and analysis tonight and put together my own guide. Let me know what you think.
First, I've expanded on the two Earth- categories. I've defined four categories.
Earth-like
Earth-similar
Earth-twin
Earth-survivable (this is a special category meaning "habitable")
Second, I've defined five criteria:
A) Mass
B) Radius
C) Mean surface temperature
D) Breathable atmosphere
E) Liquid water
To meet criteria A and/or B, a candidate planet must be within 50% of Earth's value for that particular criterion.
Me = 5.97 x 10^24 kg
Re = 6371 km
To meet criterion C, a candidate planet must be within 25% of Earth's mean surface temperature.
Temst = 287 K
Criteria D and E are boolean values.
A candidate planet matching any of
- 2 criteria is Earth-like,
- 3 or 4 criteria is Earth-similar,
- 5 criteria is Earth-twin.
In addition, a candidate planet matching criteria C, D, and E is defined as Earth-survivable. Meaning a human could survive indefinitely on the planet's surface without technological assistance. Note this does not imply criteria A and B are necessarily met. For example, a planet may may have a much lower mass and a much smaller radius but still may be survivable.
Using my guide, both Mars and Venus are Earth-like. Mars meets criteria B and C. Venus meets criteria A and B.
Kepler would be able to categorize planets as Earth-similar planets at best, although some of them may later be determined to be Earth-twins or Earth-survivable by other scientific means.
First, I've expanded on the two Earth- categories. I've defined four categories.
Earth-like
Earth-similar
Earth-twin
Earth-survivable (this is a special category meaning "habitable")
Second, I've defined five criteria:
A) Mass
B) Radius
C) Mean surface temperature
D) Breathable atmosphere
E) Liquid water
To meet criteria A and/or B, a candidate planet must be within 50% of Earth's value for that particular criterion.
Me = 5.97 x 10^24 kg
Re = 6371 km
To meet criterion C, a candidate planet must be within 25% of Earth's mean surface temperature.
Temst = 287 K
Criteria D and E are boolean values.
A candidate planet matching any of
- 2 criteria is Earth-like,
- 3 or 4 criteria is Earth-similar,
- 5 criteria is Earth-twin.
In addition, a candidate planet matching criteria C, D, and E is defined as Earth-survivable. Meaning a human could survive indefinitely on the planet's surface without technological assistance. Note this does not imply criteria A and B are necessarily met. For example, a planet may may have a much lower mass and a much smaller radius but still may be survivable.
Using my guide, both Mars and Venus are Earth-like. Mars meets criteria B and C. Venus meets criteria A and B.
Kepler would be able to categorize planets as Earth-similar planets at best, although some of them may later be determined to be Earth-twins or Earth-survivable by other scientific means.
QUOTE (Syrinx @ Nov 5 2009, 02:15 AM)
I searched for a scientific guide on what qualifies as Earth-like or Earth-twin. Didn't find anything.
Astronomers can't even define a planet, much less an Earthlike one
Rather than "Earthlike" I might suggest "habitable" and start with the criteria in the classic "Habitable Planets for Man" by Stephen Dole, now available online http://www.rand.org/pubs/commercial_books/CB179-1/
QUOTE (Syrinx @ Nov 5 2009, 04:15 AM)
For example, a planet may may have a much lower mass and a much smaller radius but still may be survivable.
We have no idea what the long term effects of low gravity on living organisms are, beyond two and a half years of lunar gravity on completely dormant microorganisms. Particularly if "survivable" means multi-generation sustainable.
QUOTE (mcaplinger @ Nov 5 2009, 09:28 AM)
...Rather than "Earthlike" I might suggest "habitable"....[/url]
"Habitable for man" refers to a specific point in Earth's life. Life arose on this planet in very inhabitable circumstances from a human point of view. I'd think that Earth-like or Earth twin could refer to a planet that might resemble Earth at any point in its history.
edit: Perhaps you meant habitable by any life as we know it, not just human life.
mcaplinger:
In my guide, Earth-like in no way implies habitable. A planet may meet criteria A, B, and C but might have a toxic atmosphere, for example. "Habitable" may be a better description for the "Earth-survivable" category.
Also, thank you for the link to the book. I'll definitely pick that up.
Holder:
There are many ways we can define survivable, and it's literally impossible to do so accurately with so few criteria. I used the phrase "survive indefinitely" but obviously that's not realistic because it implies a ready food source. For now I'll agree that certain criteria may be missing out of need for simplicity.
After a few hours to think about it, I've decided to tweak a few points from my original definitions. I'll change the mass and radius criteria to a tolerance of 50%. Surface temperature will remain with a tolerance of 25%. Mars now qualifies as Earth-like based on radius and surface temperature. Venus remains Earth-like based on radius and mass. Editing original post now... check above.
In my guide, Earth-like in no way implies habitable. A planet may meet criteria A, B, and C but might have a toxic atmosphere, for example. "Habitable" may be a better description for the "Earth-survivable" category.
Also, thank you for the link to the book. I'll definitely pick that up.
Holder:
There are many ways we can define survivable, and it's literally impossible to do so accurately with so few criteria. I used the phrase "survive indefinitely" but obviously that's not realistic because it implies a ready food source. For now I'll agree that certain criteria may be missing out of need for simplicity.
After a few hours to think about it, I've decided to tweak a few points from my original definitions. I'll change the mass and radius criteria to a tolerance of 50%. Surface temperature will remain with a tolerance of 25%. Mars now qualifies as Earth-like based on radius and surface temperature. Venus remains Earth-like based on radius and mass. Editing original post now... check above.
QUOTE (mcaplinger @ Nov 5 2009, 06:28 AM)
"Habitable Planets for Man" by Stephen Dole, now available online http://www.rand.org/pubs/commercial_books/CB179-1/
I read through the PDF. Interesting read.
It's not entirely applicable, however. One problem is I'm looking for a guide that we can utilize with Kepler's discoveries, hence the Earth-like and -similar categories. Dole defines only the habitable (Earth-survivable) category.
For habitability, Dole's criteria are:
- temperature
- light (sunlight)
- gravity
- atmosphere
- water
Those match up pretty well with my five criteria. The differences being the addition of light and gravity, and the removal of radius and mass. My counterpoints to Dole:
- The sunlight criterion might shake out from the temperature, atmosphere, and water criteria. Both my guide and Dole's guide have temperature, atmosphere, and water.
- My guide sort of has gravity as well, but in the form of mass and radius. I like mass and radius over gravity because we can directly apply them to Kepler's discoveries and classify a planet as Earth-like. Whereas using gravity alone might require us to match the gravity criterion after discovering a super dense basketball.
I would ask people to refer back to the rules at this point - this discussion isn't really in the jurisdiction of UMSF, and is in danger of falling foul of several rules.
http://kepler.nasa.gov/about/manager.html
QUOTE
Kepler completed another science data download over October 18-19.
QUOTE (Byran @ Nov 5 2009, 02:28 PM)
Unfortunately, public data (calibrating photometry for 10 days May 2009) there is no known transiting planets, or short period known variables.
Found only long period variable - U Lyr (Mira type)
http://simbad4.cfa.harvard.edu:8080/simbad...p;submit=submit
other star from public data Kepler
http://simbad4.cfa.harvard.edu:8080/simbad...p;submit=submit
not variable in Simbad
p-mode K-giant star?
From the latest mission report
So we finally get it from the horse's mouth. It's still short on the specifics, but they are essentially telling us that:
i) The worst sources of noise are restricted to a small number of detectors.
ii) The raw data from Kepler can be processed and reprocessed as the sources of noise are characterized and countered. This holds true for the worst affected detectors though it will take more time to clean up those signals, and thus a delay in finding a minority of the detectable Earth-sized planets.
No doubt one can surmise that the noisier channels will never be made as clean as the better behaving channels, but they still seem to be implying that they will be able to squeeze Earth-sized planets out of all the data eventually.
It should help that the majority of transits with periods much shorter than a year will not fall on the same detectors so, for example, if one transit of a planet with a 3 month orbit hits a noisy detector, there will three other transits detected by low noise channels, thus the team will know where to look for a transit in the noisy data too. That should help calibrate and confirm their "noise abatement" algorithms as they proceed.
QUOTE
Random noise is present in all measurements and cannot be calibrated out. Therefore, strict requirements were placed on the design of Kepler’s spacecraft systems to limit random noise to a low level. Measurements taken in space confirm that Kepler meets its random noise requirements.
Systematic noise results from the imperfect nature of any measuring device. It represents the instrument’s “finger print” placed upon the measurement, and must be calibrated out of the data in post-processing on the ground. Because systematic noise depends on the specific characteristics of the instrument, the best calibration requires that the noise sources be characterized and modeled based on measurements made in space. The Kepler team has been developing the ground software to calibrate out the various systematic noise sources since launch, and this work will continue for a number of months. As each source of systematic noise is calibrated, fainter transit signals can be detected. Data collected from the spacecraft will be continually reprocessed as the ground software matures, revealing smaller and smaller planets. This is a normal process and has been part of the Kepler plan since before launch. Fortunately for Kepler, the worst sources of systematic noise affect only a small portion of the field of view, so the majority of the field of view will be calibrated earlier, enabling small planets to be detected sooner.
Systematic noise results from the imperfect nature of any measuring device. It represents the instrument’s “finger print” placed upon the measurement, and must be calibrated out of the data in post-processing on the ground. Because systematic noise depends on the specific characteristics of the instrument, the best calibration requires that the noise sources be characterized and modeled based on measurements made in space. The Kepler team has been developing the ground software to calibrate out the various systematic noise sources since launch, and this work will continue for a number of months. As each source of systematic noise is calibrated, fainter transit signals can be detected. Data collected from the spacecraft will be continually reprocessed as the ground software matures, revealing smaller and smaller planets. This is a normal process and has been part of the Kepler plan since before launch. Fortunately for Kepler, the worst sources of systematic noise affect only a small portion of the field of view, so the majority of the field of view will be calibrated earlier, enabling small planets to be detected sooner.
So we finally get it from the horse's mouth. It's still short on the specifics, but they are essentially telling us that:
i) The worst sources of noise are restricted to a small number of detectors.
ii) The raw data from Kepler can be processed and reprocessed as the sources of noise are characterized and countered. This holds true for the worst affected detectors though it will take more time to clean up those signals, and thus a delay in finding a minority of the detectable Earth-sized planets.
No doubt one can surmise that the noisier channels will never be made as clean as the better behaving channels, but they still seem to be implying that they will be able to squeeze Earth-sized planets out of all the data eventually.
It should help that the majority of transits with periods much shorter than a year will not fall on the same detectors so, for example, if one transit of a planet with a 3 month orbit hits a noisy detector, there will three other transits detected by low noise channels, thus the team will know where to look for a transit in the noisy data too. That should help calibrate and confirm their "noise abatement" algorithms as they proceed.
The words that stand out to this layperson, in the context of the news report, are
QUOTE
This is a normal process and has been part of the Kepler plan since before launch.
The third safing event, no science lost as this was just before a successful download.
QUOTE (Holder of the Two Leashes @ Nov 24 2009, 03:12 PM)
The third safing event, no science lost as this was just before a successful download.
I was initially worried that the safing events would create too many gaps in the data for transits to fall into, but I guess that the odds of them losing more than one instance of the same planetary transit are small, and should they discover that two other transit instances line up with one of the gaps in the data, they can infer that there likely was a transit during that time.
Not long now before the first full science results are released -- a couple of months away, or so.
TIME is reporting that "[The Kepler team] has already submitted 28 scientific papers based on 43 days of data or less," says MIT planet theorist Sara Seager. "It's going to be a big year for planets."
Entire article here
I am getting pretty excited about the coming new year!
Entire article here
I am getting pretty excited about the coming new year!
That link does not seem to be about Kepler and 28 papers......
MahFL, the reference about Kepler is at like the last paragraph. Just search (Ctrl + F) "Kepler" and it takes you right to it ^.^
You're correct, it's not. But it does have this:
QUOTE
Separately, NASA's Kepler Mission will present the first results of its planet search at the American Astronomical Society meeting in Washington in January. "[The Kepler team] has already submitted 28 scientific papers based on 43 days of data or less," says MIT planet theorist Sara Seager. "It's going to be a big year for planets."
Ah in my unfamiliarity with that website I did not notice the + sign.
QUOTE (MahFL @ Dec 18 2009, 03:35 PM)
That link does not seem to be about Kepler and 28 papers......
Interesting though about the red dwarf watery planet. Will Kepler also be looking for some of these?
The real planetary scientists here may have something to say about this, but I would bet that Thalassan type planets [named for the fictional waterworld of Clarke's "Songs of Distant Earth] will be quite prevalent. Kepler may well find many of them in a habitable zone.
Yes, and since they would have shorter orbital periods they could dominate the initial findings.
QUOTE (Syrinx @ Nov 5 2009, 10:15 AM)
Second, I've defined five criteria:
A) Mass
Radius
C) Mean surface temperature
D) Breathable atmosphere
E) Liquid water
A) Mass
RadiusC) Mean surface temperature
D) Breathable atmosphere
E) Liquid water
I wonder if Kepler or other observations would be able to address criterion C if it found a Venus like planet.
Another criterion could be density (more closely constraining mass and radius) to look for rocky planets.
Kepler will be able to tell us how far away the planet is from its star and we will have very good measures of its energy output. It will be easy to figure out how much energy is delivered to the planet and how that energy is distributed. Spectral evidence of the presence of an atmosphere will probably have to come from the larger scopes.
Density is calculated from mass and radius. Mass is determined by the orbit. The reason they are suggest that this new planet is a water world is from the calculations of its density, showing that it was made up of a lot of water. I am pretty sure that Kepler will constrain the radius of exoplanets more precisely than any Earth based telescope.
Any planet with a lot of water that is within its star's habitable zone, or closer, will have a surface that is liquid water. (I can imagine an "ice cap" forming on the anti-stellar side of a tidally locked world, but that will depend on how well the atmosphere distributes the heat.) I'd be really surprised if these kind of worlds were not very common among the Earth-sized planets that Kepler finds.
Density is calculated from mass and radius. Mass is determined by the orbit. The reason they are suggest that this new planet is a water world is from the calculations of its density, showing that it was made up of a lot of water. I am pretty sure that Kepler will constrain the radius of exoplanets more precisely than any Earth based telescope.
Any planet with a lot of water that is within its star's habitable zone, or closer, will have a surface that is liquid water. (I can imagine an "ice cap" forming on the anti-stellar side of a tidally locked world, but that will depend on how well the atmosphere distributes the heat.) I'd be really surprised if these kind of worlds were not very common among the Earth-sized planets that Kepler finds.
The tricky part of the Venus scenario is that there are two factors that add on to a first-order temperature calculation. First its high albedo should make it cooler than "expected" though placing it within habitable surface conditions. Second and more importantly its greenhouse effect makes it very much hotter as a net result. This type of thing might be more difficult to infer.
Modeling the atmospheres and the effects of them on these "hot" planets is and will be tricky. Well beyond my abilities. I think that why we will need to get spectra of the worlds that Kepler discovers with larger scopes. Ultimately, this will be an important job for the JWST.
QUOTE (Ron Hobbs @ Dec 19 2009, 12:44 PM)
The reason they are suggest that this new planet is a water world is from the calculations of its density, showing that it was made up of a lot of water.
Rubbing alcohol has a density 90% that of H2O. How can we be so sure GJ 1214b isn't a "rubbing alcohol world"? Honest question; I don't know the answer.
Probability, I'd say. H2O is a far more cosmically abundant compound than any alcohol...Occam's Razor.
There's a short article in the January 2010 Scientific American (p. 26) where they discuss the possibility of carbon planets. They could be made of carbon or related compounds instead of oxygen rich compounds. Maybe Kepler will find some of these?
QUOTE (scalbers @ Dec 20 2009, 08:57 AM)
There's a short article in the January 2010 Scientific American (p. 26) where they discuss the possibility of carbon planets. They could be made of carbon or related compounds instead of oxygen rich compounds. Maybe Kepler will find some of these?
Sure it might -- but without spectroscopy it will be hard to tell which ones are Carbon-worlds and which are Oxygen worlds! The densities aren't distinct enough to allow Kepler to differentiate.
- Jason
QUOTE (Ron Hobbs @ Dec 19 2009, 11:31 AM)
. . . I would bet that Thalassan type planets [named for the fictional waterworld of Clarke's "Songs of Distant Earth] will be quite prevalent.
Thalassa was an ancient greek water goddess, and her name gets used a lot for things of this sort. For example, the ancient supercontinent, Pangaea, was surrounded by a world ocean, Panthalassa. I suspect that's where Clarke got his title. I don't think it works the other way around! ;-)
But I definitely agree that I don't know of any mechanism to soak up excess water from such a world. There may be a very narrow margin between a world with too little water and one with oceans a hundred miles deep, and the odds on getting a world that's "just right" may be fairly low. I don't know of anything planned that could answer this, though.
--Greg
Maybe I overstepped my bounds, but I was just using Clarke's name for the water-world in his story as a descriptor of water-worlds in general. I am sure that Clarke used the name of the goddess for his planet because of the custom of using the names Greaco-Roman gods and goddess for planets in this Solar System. I think it is not a bad nominative for what I think will be a large class of exoplanets.
I think for the "hot" worlds (those within the habitable zone of a star) the water gets boiled off, dissociated by the UV from the star and the hydrogen is lost and blown away by the stellar wind. If I understand correctly, Venus was once a hot water world (at least it had an ocean that is now gone). What Kepler will give us, hopefully, is examples of Venus-like worlds at different ages. That is sure to inform the speculation of what happened to the oceans of Venus.
Ron
I think for the "hot" worlds (those within the habitable zone of a star) the water gets boiled off, dissociated by the UV from the star and the hydrogen is lost and blown away by the stellar wind. If I understand correctly, Venus was once a hot water world (at least it had an ocean that is now gone). What Kepler will give us, hopefully, is examples of Venus-like worlds at different ages. That is sure to inform the speculation of what happened to the oceans of Venus.
Ron
It's in the last paragraph.
EDIT: oops, I was responding to a previous post about the Time article, but someone already pointed that out
EDIT: oops, I was responding to a previous post about the Time article, but someone already pointed that out
latest update: http://www.nasa.gov/mission_pages/kepler/n...m-20091223.html
Neat - the AAS conference with results already coming up in the next couple of weeks.
http://www.abstractsonline.com/plan/Browse...7a-f0cf7b29b41f
http://www.abstractsonline.com/plan/ViewAb...bf-512927a1bafb
Presentation Number 101.01
Presentation Time: Monday, Jan 04, 2010, 8:30 AM - 9:20 AM
Title Kepler Planet Detection Mission: Introduction and First Results
Author Block William J. Borucki1, D. Koch1, G. Basri2, N. M. Batalha3, T. Brown4, D. A. Caldwell5, J. Caldwell6, J. Christensen-Dalsgaard7, W. Cochran8, E. DeVore5, E. Dunham9, A. Dupree10, T. Gautier11, J. Geary10, R. Gilliland12, A. Gould13, S. Howell14, J. Jenkins5, H. Kjeldsen7, Y. Kondo15, D. Latham10, J. Lissauer1, G. Marcy2, S. Meibom10, D. Monet16, D. Morrison1, D. Sasselov17, J. Tarter5
1NASA/Ames Research Center, 2University of California, 3San Jose State Universiy, 4Los Cumbres Observatory Global Telescope, 5SETI Institute, 6York University, Canada, 7Aarhus University, Denmark, 8University of Texas, 9Lowell Observatory, 10SAO, 11JPL, 12STScI, 13Lawrence Hall of Science, 14NOAO, 15NASA GSFC, 16US Naval Observatory, 17Harvard.
Abstract The Kepler Mission is designed to determine the frequency of Earth-size and terrestrial size planets in and near the HZ of solar-like stars. It was competitively selected as Discovery Mission #10 and launched on March 6, 2009. Since completion of commissioning, it has continuously observed over 145,000 main sequence stars. The photometric precision reaches 20 ppm for 12th magnitude stars on the least noisy detectors in 6.5 hours. During the first month of operation, the photometer detected transit-like signatures from over 100 stars. Careful examination of these events shows many of them to be false-positives such as background eclipsing binaries. However ground-based follow up observations confirm the discovery of exoplanets with sizes ranging from 0.6 Rj to1.5Rj and orbital periods ranging from 3 to 9 days. Observations at Keck, Hobby-Eberly, Harlan-Smith, WIYN, MMT, Tillighast, Shane, and Nordic Optic telescopes are vetting many of the candidates and measuring their masses. Discovery of the HAT-P7b occultation will be used to derive atmospheric properties and demonstrates the precision necessary to detect Earth-size planets. Asteroseismic analyses of several stars show the presence of p-mode oscillations that can be used to determine stellar size and age. This effort is being organized by the Kepler Asteroseismic Science Consortium at Aarhus University in Denmark. Stellar parallaxes are determined from the centroid motion of the stellar images and will be combined with photometric measurements to get the sizes of stars too dim for asteroseismic measurement. Four open clusters are being observed to determine rotation rates with stellar age and spectral type. Many types of stellar variability are observed with unprecedented precision and over long continuous time periods. Examples of many of these discoveries are presented. Funding by the Exoplanet Exploration Program of the NASA Astrophysics Division is gratefully acknowledged.
http://www.abstractsonline.com/plan/Browse...7a-f0cf7b29b41f
http://www.abstractsonline.com/plan/ViewAb...bf-512927a1bafb
Presentation Number 101.01
Presentation Time: Monday, Jan 04, 2010, 8:30 AM - 9:20 AM
Title Kepler Planet Detection Mission: Introduction and First Results
Author Block William J. Borucki1, D. Koch1, G. Basri2, N. M. Batalha3, T. Brown4, D. A. Caldwell5, J. Caldwell6, J. Christensen-Dalsgaard7, W. Cochran8, E. DeVore5, E. Dunham9, A. Dupree10, T. Gautier11, J. Geary10, R. Gilliland12, A. Gould13, S. Howell14, J. Jenkins5, H. Kjeldsen7, Y. Kondo15, D. Latham10, J. Lissauer1, G. Marcy2, S. Meibom10, D. Monet16, D. Morrison1, D. Sasselov17, J. Tarter5
1NASA/Ames Research Center, 2University of California, 3San Jose State Universiy, 4Los Cumbres Observatory Global Telescope, 5SETI Institute, 6York University, Canada, 7Aarhus University, Denmark, 8University of Texas, 9Lowell Observatory, 10SAO, 11JPL, 12STScI, 13Lawrence Hall of Science, 14NOAO, 15NASA GSFC, 16US Naval Observatory, 17Harvard.
Abstract The Kepler Mission is designed to determine the frequency of Earth-size and terrestrial size planets in and near the HZ of solar-like stars. It was competitively selected as Discovery Mission #10 and launched on March 6, 2009. Since completion of commissioning, it has continuously observed over 145,000 main sequence stars. The photometric precision reaches 20 ppm for 12th magnitude stars on the least noisy detectors in 6.5 hours. During the first month of operation, the photometer detected transit-like signatures from over 100 stars. Careful examination of these events shows many of them to be false-positives such as background eclipsing binaries. However ground-based follow up observations confirm the discovery of exoplanets with sizes ranging from 0.6 Rj to1.5Rj and orbital periods ranging from 3 to 9 days. Observations at Keck, Hobby-Eberly, Harlan-Smith, WIYN, MMT, Tillighast, Shane, and Nordic Optic telescopes are vetting many of the candidates and measuring their masses. Discovery of the HAT-P7b occultation will be used to derive atmospheric properties and demonstrates the precision necessary to detect Earth-size planets. Asteroseismic analyses of several stars show the presence of p-mode oscillations that can be used to determine stellar size and age. This effort is being organized by the Kepler Asteroseismic Science Consortium at Aarhus University in Denmark. Stellar parallaxes are determined from the centroid motion of the stellar images and will be combined with photometric measurements to get the sizes of stars too dim for asteroseismic measurement. Four open clusters are being observed to determine rotation rates with stellar age and spectral type. Many types of stellar variability are observed with unprecedented precision and over long continuous time periods. Examples of many of these discoveries are presented. Funding by the Exoplanet Exploration Program of the NASA Astrophysics Division is gratefully acknowledged.
Link doesn't work for me, as is so for all abstractsonline links. I've heard one must go through their main page to find abstracts but I never seem to be able to find any abstracts doing that.
QUOTE (Hungry4info @ Dec 24 2009, 12:26 PM)
Link doesn't work for me, as is so for all abstractsonline links. I've heard one must go through their main page to find abstracts but I never seem to be able to find any abstracts doing that.
Hungry4info.... go to http://aas.org/meetings/aas215
Click on "Program and Block Schedule" on the right hand side of the page
On the next page click on "Meeting Program and Itinerary Builder"
Then click on "Browse" and you can choose by session day or category.
Straight forward, huh!!!!
Craig
Ah, thanks for that. I was trying to go through abstractsonline dot com and navigate from there. =S
QUOTE (Hungry4info @ Dec 26 2009, 04:06 PM)
Ah, thanks for that. I was trying to go through abstractsonline dot com and navigate from there. =S
I have had problems my self using the abstratonline service. If I know an abstract is from a meeting venue I usually go straight to that venue.
As for a Kepler related note I found this reference on the Extrsolar Visions forum... seems like the original source document was removed off the ESA site but found a truncated version here: http://www.docstoc.com/docs/15604836/2-Sci...a-solar-planets first page
"very recent detections with the Kepler satellite of a large population of close-in, small transiting objects (2-4 earth radii, private communication) awaiting to be confirmed by radial-velocity observations."
-
I know the source document is recent because some of the figures note GJ 1214b (a show stopping discovery by the MEarth project - "which has a mass of 6.55M⊕ and a
radius 2.68 times Earth’s radius (R⊕), indicating that it is intermediate in stature between Earth and the ice giants of the Solar System.")
http://fr.arxiv.org/ftp/arxiv/papers/0912/0912.3229.pdf
Craig
NASA to Unveil Kepler Space Telescope Discoveries
Rumors? Bets? Wild speculations?
Rumors? Bets? Wild speculations?
Having worked in PR for years, I'd say this line gives a clue:
Although the news conference will not be broadcast live on NASA Television, Kepler video will be aired on NASA TV immediately following the news briefing on the media channel.
That tells me it's interesting but probably not headline grabbing. I would expect that if it was something really huge they'd get the full, live NASA TV feed, and they'd have some higher up NASA bigwigs there. Worthy of guesses, but at this point the wild speculation would be unwarranted.
Although the news conference will not be broadcast live on NASA Television, Kepler video will be aired on NASA TV immediately following the news briefing on the media channel.
That tells me it's interesting but probably not headline grabbing. I would expect that if it was something really huge they'd get the full, live NASA TV feed, and they'd have some higher up NASA bigwigs there. Worthy of guesses, but at this point the wild speculation would be unwarranted.
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