Author Topic: NASA - Kepler updates  (Read 162328 times)

Offline jacqmans

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Re: NASA - Kepler updates
« Reply #60 on: 01/10/2011 06:03 PM »
RELEASE: 11-007

NASA'S KEPLER MISSION DISCOVERS ITS FIRST ROCKY PLANET

WASHINGTON -- NASA's Kepler mission confirmed the discovery of its
first rocky planet, named Kepler-10b. Measuring 1.4 times the size of
Earth, it is the smallest planet ever discovered outside our solar
system.

The discovery of this so-called exoplanet is based on more than eight
months of data collected by the spacecraft from May 2009 to early
January 2010.

"All of Kepler's best capabilities have converged to yield the first
solid evidence of a rocky planet orbiting a star other than our sun,"
said Natalie Batalha, Kepler's deputy science team lead at NASA's
Ames Research Center in Moffett Field, Calif., and primary author of
a paper on the discovery accepted by the Astrophysical Journal. "The
Kepler team made a commitment in 2010 about finding the telltale
signatures of small planets in the data, and it's beginning to pay
off."

Kepler's ultra-precise photometer measures the tiny decrease in a
star's brightness that occurs when a planet crosses in front of it.
The size of the planet can be derived from these periodic dips in
brightness. The distance between the planet and the star is
calculated by measuring the time between successive dips as the
planet orbits the star.

Kepler is the first NASA mission capable of finding Earth-size planets
in or near the habitable zone, the region in a planetary system where
liquid water can exist on the planet's surface. However, since it
orbits once every 0.84 days, Kepler-10b is more than 20 times closer
to its star than Mercury is to our sun and not in the habitable zone.


Kepler-10 was the first star identified that could potentially harbor
a small transiting planet, placing it at the top of the list for
ground-based observations with the W.M. Keck Observatory 10-meter
telescope in Hawaii.

Scientists waiting for a signal to confirm Kepler-10b as a planet were
not disappointed. Keck was able to measure tiny changes in the star's
spectrum, called Doppler shifts, caused by the telltale tug exerted
by the orbiting planet on the star.

"The discovery of Kepler 10-b is a significant milestone in the search
for planets similar to our own," said Douglas Hudgins, Kepler program
scientist at NASA Headquarters in Washington. "Although this planet
is not in the habitable zone, the exciting find showcases the kinds
of discoveries made possible by the mission and the promise of many
more to come," he said.

Knowledge of the planet is only as good as the knowledge of the star
it orbits. Because Kepler-10 is one of the brighter stars being
targeted by Kepler, scientists were able to detect high frequency
variations in the star's brightness generated by stellar
oscillations, or starquakes. This analysis allowed scientists to pin
down Kepler-10b's properties.

There is a clear signal in the data arising from light waves that
travel within the interior of the star. Kepler Asteroseismic Science
Consortium scientists use the information to better understand the
star, just as earthquakes are used to learn about Earth's interior
structure. As a result of this analysis, Kepler-10 is one of the most
well characterized planet-hosting stars in the universe.

That's good news for the team studying Kepler-10b. Accurate stellar
properties yield accurate planet properties. In the case of
Kepler-10b, the picture that emerges is of a rocky planet with a mass
4.6 times that of Earth and with an average density of 8.8 grams per
cubic centimeter -- similar to that of an iron dumbbell.

Ames manages Kepler's ground system development, mission operations
and science data analysis. NASA's Jet Propulsion Laboratory in
Pasadena, Calif., managed Kepler mission development.

Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the
Kepler flight system and supports mission operations with the
Laboratory for Atmospheric and Space Physics at the University of
Colorado in Boulder. The Space Telescope Science Institute in
Baltimore archives, hosts and distributes the Kepler science data.

Kepler is NASA's 10th Discovery Mission and is funded by NASA's
Science Mission Directorate at the agency's headquarters. For more
information about the Kepler mission, visit:



http://www.nasa.gov/kepler


Online Robotbeat

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Re: NASA - Kepler updates
« Reply #61 on: 01/10/2011 06:38 PM »
What does the light curve look like?
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Offline TheFallen

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Re: NASA - Kepler updates
« Reply #62 on: 01/27/2011 05:30 PM »
NASA To Announce New Planetary Discoveries on February 2nd

News briefing about the Kepler mission will be held that day at 1 PM, EST.

http://www.nasa.gov/home/hqnews/2011/jan/HQ_M11-020_Kepler.html
« Last Edit: 01/27/2011 05:33 PM by TheFallen »

Offline robertross

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Re: NASA - Kepler updates
« Reply #63 on: 02/02/2011 01:11 PM »
A quick peek before the announcement today:

1,000 possible new planets found
90 per cent of discoveries by Kepler telescope expected to be verified as planets

http://www.cbc.ca/technology/story/2011/02/02/science-space-kepler-planets.html
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Offline stockman

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Re: NASA - Kepler updates
« Reply #64 on: 02/02/2011 01:21 PM »
A quick peek before the announcement today:

1,000 possible new planets found
90 per cent of discoveries by Kepler telescope expected to be verified as planets

http://www.cbc.ca/technology/story/2011/02/02/science-space-kepler-planets.html

Thanks Robertross - this is truly great news if accurate...
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Offline John44

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Re: NASA - Kepler updates
« Reply #65 on: 02/02/2011 07:10 PM »

Offline ugordan

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Re: NASA - Kepler updates
« Reply #66 on: 02/02/2011 07:21 PM »
I missed the briefing so thank you very much for that, John.

Offline robertross

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Re: NASA - Kepler updates
« Reply #67 on: 02/02/2011 08:03 PM »

Feb. 02, 2011 RELEASE : 11-030 

NASA Finds Earth-Size Planet Candidates In Habitable Zone, Six Planet System   

WASHINGTON -- NASA's Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet's surface. Five of the potential planets are near Earth-size and orbit in the habitable zone of smaller, cooler stars than our sun.

Candidates require follow-up observations to verify they are actual planets. Kepler also found six confirmed planets orbiting a sun-like star, Kepler-11. This is the largest group of transiting planets orbiting a single star yet discovered outside our solar system.

"In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today's reality," said NASA Administrator Charles Bolden. "These discoveries underscore the importance of NASA's science missions, which consistently increase understanding of our place in the cosmos."

The discoveries are part of several hundred new planet candidates identified in new Kepler mission science data, released on Tuesday, Feb. 1. The findings increase the number of planet candidates identified by Kepler to-date to 1,235. Of these, 68 are approximately Earth-size; 288 are super-Earth-size; 662 are Neptune-size; 165 are the size of Jupiter and 19 are larger than Jupiter.

Of the 54 new planet candidates found in the habitable zone, five are near Earth-sized. The remaining 49 habitable zone candidates range from super-Earth size -- up to twice the size of Earth -- to larger than Jupiter.

The findings are based on the results of observations conducted May 12 to Sept. 17, 2009, of more than 156,000 stars in Kepler's field of view, which covers approximately 1/400 of the sky.

"The fact that we've found so many planet candidates in such a tiny fraction of the sky suggests there are countless planets orbiting sun-like stars in our galaxy," said William Borucki of NASA's Ames Research Center in Moffett Field, Calif., the mission's science principal investigator. "We went from zero to 68 Earth-sized planet candidates and zero to 54 candidates in the habitable zone, some of which could have moons with liquid water."

Among the stars with planetary candidates, 170 show evidence of multiple planetary candidates. Kepler-11, located approximately 2,000 light years from Earth, is the most tightly packed planetary system yet discovered. All six of its confirmed planets have orbits smaller than Venus, and five of the six have orbits smaller than Mercury's. The only other star with more than one confirmed transiting planet is Kepler-9, which has three. The Kepler-11 findings will be published in the Feb. 3 issue of the journal Nature.

"Kepler-11 is a remarkable system whose architecture and dynamics provide clues about its formation," said Jack Lissauer, a planetary scientist and Kepler science team member at Ames. "These six planets are mixtures of rock and gases, possibly including water. The rocky material accounts for most of the planets' mass, while the gas takes up most of their volume. By measuring the sizes and masses of the five inner planets, we determined they are among the lowest mass confirmed planets beyond our solar system."

All of the planets orbiting Kepler-11 are larger than Earth, with the largest ones being comparable in size to Uranus and Neptune. The innermost planet, Kepler-11b, is ten times closer to its star than Earth is to the sun. Moving outward, the other planets are Kepler-11c, Kepler-11d, Kepler-11e, Kepler-11f, and the outermost planet, Kepler-11g, which is half as far from its star as Earth is from the sun.

The planets Kepler-11d, Kepler-11e and Kepler-11f have a significant amount of light gas, which indicates that they formed within a few million years of the system's formation.

"The historic milestones Kepler makes with each new discovery will determine the course of every exoplanet mission to follow," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington.

Kepler, a space telescope, looks for planet signatures by measuring tiny decreases in the brightness of stars caused by planets crossing in front of them. This is known as a transit.

Since transits of planets in the habitable zone of sun-like stars occur about once a year and require three transits for verification, it is expected to take three years to locate and verify Earth-size planets orbiting sun-like stars.

The Kepler science team uses ground-based telescopes and the Spitzer Space Telescope to review observations on planetary candidates and other objects of interest the spacecraft finds.

The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations help determine which candidates can be validated as planets.

For more information about the Kepler mission, visit:

http://www.nasa.gov/kepler   
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Online Robotbeat

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Re: NASA - Kepler updates
« Reply #68 on: 02/02/2011 09:28 PM »
Wow...
A near-Earth-mass planet in the habitable zone... This day was inevitable and now it has come!
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Offline robertross

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Re: NASA - Kepler updates
« Reply #69 on: 02/02/2011 09:30 PM »
"In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today's reality," said NASA Administrator Charles Bolden. "These discoveries underscore the importance of NASA's science missions, which consistently increase understanding of our place in the cosmos."

One of the best quotes I've heard from Bolden yet.
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Offline Nittany Lion

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Re: NASA - Kepler updates
« Reply #70 on: 02/02/2011 09:48 PM »
Iím trying to get an intellectual handle on the number of candidate exoplanets being reported by Kepler. Maybe someone here can help.

Here are the issues;

(1) Kepler is observing an area of the sky 10 degrees by 10 degrees, so about one-four hundredth of the whole celestial sphere.

(2) Kepler currently has had a sufficient observing interval to observe exoplanets with revolving periods up to four months. The habitable zone extends to something like revolving periods of eighteen months. So currently Kepler has observed for say one-fourth of the time required to observe all potentially habitable exoplanets.

Thatís the easy part. Now;

(3) The transit technique used by Kepler requires that the plane of the exoplanetsís orbit must include the line of sight between the Earth and the star the exoplanet orbits.

Given that even very large and very close stars subtend very small angles when observed from Earth and most stars are effectively point sources, what proportion of exoplanet orbits satisfy the planar requirement described above?

Iím thinking that proportion is between one in one thousand, and one in one hundred thousand.

So the Kepler candidate count announced today needs to be multiplied by between (400)(4)(1,000) = 1,600,000 and (400)(4)(100,000) = 160,0000,000.

And the total number of exoplanet candidates orbiting within the habitable zone or closer would be between (1,600,000)(1,250) = 2 billion and (160,0000,000)(1,250) = 200 billion, all with about 2000 light-years!

Thoughts?


Online Robotbeat

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Re: NASA - Kepler updates
« Reply #71 on: 02/02/2011 10:25 PM »
....
(2) Kepler currently has had a sufficient observing interval to observe exoplanets with revolving periods up to four months. The habitable zone extends to something like revolving periods of eighteen months. So currently Kepler has observed for say one-fourth of the time required to observe all potentially habitable exoplanets.
...
Three transits are required for sure detection of an exoplanet, so for detecting Earth from far away using  Kepler's techniques would require between 24 and 36 months (plus the good fortune of your detector being in plane with the star system's Ecliptic).

Stars smaller (or much smaller) than the Sun have a habitable zone closer (or much closer) in. Those are the sort of stars around which Kepler has found planets in the habitable zone since Kepler has only been operating for about 22 months. I.e. Red dwarfs.
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Offline Nittany Lion

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Re: NASA - Kepler updates
« Reply #72 on: 02/02/2011 11:10 PM »
....
(2) Kepler currently has had a sufficient observing interval to observe exoplanets with revolving periods up to four months. The habitable zone extends to something like revolving periods of eighteen months. So currently Kepler has observed for say one-fourth of the time required to observe all potentially habitable exoplanets.
...
Three transits are required for sure detection of an exoplanet, so for detecting Earth from far away using  Kepler's techniques would require between 24 and 36 months (plus the good fortune of your detector being in plane with the star system's Ecliptic).

Stars smaller (or much smaller) than the Sun have a habitable zone closer (or much closer) in. Those are the sort of stars around which Kepler has found planets in the habitable zone since Kepler has only been operating for about 22 months. I.e. Red dwarfs.

"plus the good fortune of your detector being in plane with the star system's Ecliptic"

Thus my point (3) which is the dominating effect in the calculation.

Offline kkattula

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Re: NASA - Kepler updates
« Reply #73 on: 02/03/2011 12:58 AM »

"plus the good fortune of your detector being in plane with the star system's Ecliptic"

Thus my point (3) which is the dominating effect in the calculation.


http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Objectives_and_methods

Quote
The probability of a random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit.[16] For an Earth-like planet at 1 AU transiting a Sol-like star the probability is 0.465%, or about 1 in 215. At 0.72 AU (the orbital distance of Venus) the probability is slightly larger, at 0.65%; such planets could be Earth-like if the host star is a late G-type star such as Tau Ceti. In addition, because planets in a given system tend to orbit in similar planes, the possibility of multiple detections around a single star is actually rather high. For instance, if an alien Kepler-like mission observed Earth transiting the Sun, there is a 12% chance of also seeing Venus transit.

16  David Koch; Alan Gould (March 2009). "Kepler Mission: Characteristics of Transits (section “Geometric Probability”)". NASA. http://jwleaf.org/docs/probability-of-planetary-transit.html. Retrieved 2009-09-21. 


Edit: References.
« Last Edit: 02/03/2011 05:24 AM by kkattula »

Offline Nittany Lion

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Re: NASA - Kepler updates
« Reply #74 on: 02/03/2011 01:41 AM »

"plus the good fortune of your detector being in plane with the star system's Ecliptic"

Thus my point (3) which is the dominating effect in the calculation.


Quote
The probability of a random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit.[16] For an Earth-like planet at 1 AU transiting a Sol-like star the probability is 0.465%, or about 1 in 215. At 0.72 AU (the orbital distance of Venus) the probability is slightly larger, at 0.65%; such planets could be Earth-like if the host star is a late G-type star such as Tau Ceti. In addition, because planets in a given system tend to orbit in similar planes, the possibility of multiple detections around a single star is actually rather high. For instance, if an alien Kepler-like mission observed Earth transiting the Sun, there is a 12% chance of also seeing Venus transit.

Could you provide the source of that quote and the cited [16] reference?

Although the quote indicates it is answering my planar question, the process seems to be describing the probability of observing a transit of an exoplanet whose orbit is already in the required orientation, i.e., the ratio of the starís diameter to the orbitís diameter. It strikes me that this is a two dimensional answer to a three dimensional problem.

And the probability seems high.

Iím not saying itís wrong. Iíd just like to pursue it further.


Online Robotbeat

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Re: NASA - Kepler updates
« Reply #75 on: 02/03/2011 02:33 AM »

"plus the good fortune of your detector being in plane with the star system's Ecliptic"

Thus my point (3) which is the dominating effect in the calculation.


Quote
The probability of a random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit.[16] For an Earth-like planet at 1 AU transiting a Sol-like star the probability is 0.465%, or about 1 in 215. At 0.72 AU (the orbital distance of Venus) the probability is slightly larger, at 0.65%; such planets could be Earth-like if the host star is a late G-type star such as Tau Ceti. In addition, because planets in a given system tend to orbit in similar planes, the possibility of multiple detections around a single star is actually rather high. For instance, if an alien Kepler-like mission observed Earth transiting the Sun, there is a 12% chance of also seeing Venus transit.

Could you provide the source of that quote and the cited [16] reference?

Although the quote indicates it is answering my planar question, the process seems to be describing the probability of observing a transit of an exoplanet whose orbit is already in the required orientation, i.e., the ratio of the starís diameter to the orbitís diameter. It strikes me that this is a two dimensional answer to a three dimensional problem.

And the probability seems high.

Iím not saying itís wrong. Iíd just like to pursue it further.


It is a two-dimensional problem, since your distance to the star doesn't really matter (as long as you're not within the star system itself)... Well, actually, if you look at the system through a full orbit of the planet or more, then it's actually a one-dimensional problem.
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Offline kkattula

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Re: NASA - Kepler updates
« Reply #76 on: 02/03/2011 05:58 AM »
Added references to my previous post.

The thing is, a star is not a point source. It's big. Really big.

This diagram shows something like a super-Jupiter at .15 AU from a Sol like star.  Any observer anywhere in the arc a, as it rotates 360 deg around the star, will observe a transit.

Even if the planet is tiny, the arc doesn't change much. The intersection point is effectively at the planet's orbital radius

« Last Edit: 02/03/2011 06:15 AM by kkattula »

Offline Nittany Lion

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Re: NASA - Kepler updates
« Reply #77 on: 02/03/2011 03:08 PM »
Added references to my previous post.

The thing is, a star is not a point source. It's big. Really big.

This diagram shows something like a super-Jupiter at .15 AU from a Sol like star.  Any observer anywhere in the arc a, as it rotates 360 deg around the star, will observe a transit.

Even if the planet is tiny, the arc doesn't change much. The intersection point is effectively at the planet's orbital radius




Thank you for the references! The calculations are clearly correct and the probability of detection is much higher than I imagined. I think Iím handicapped by having a rectangular coordinate brain trying to deal with a spherical coordinate problem.

Great notation d* (ďd starĒ) for the diameter of the star!


Offline Malderi

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Re: NASA - Kepler updates
« Reply #78 on: 02/03/2011 03:24 PM »
Keep in mind also, that Kepler is looking in a direction in which it expected to find many stars with possible planets - it's looking down the spiral arm of the Milky Way. So just saying that it's taking 1/400 of the sky, and so multiplying discoveries by 400, is definitely a high upper bound. If it was looking perpendicular to the galactic plane, it wouldn't be seeing nearly as many stars.

Offline Nittany Lion

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Re: NASA - Kepler updates
« Reply #79 on: 02/03/2011 03:53 PM »
Keep in mind also, that Kepler is looking in a direction in which it expected to find many stars with possible planets - it's looking down the spiral arm of the Milky Way. So just saying that it's taking 1/400 of the sky, and so multiplying discoveries by 400, is definitely a high upper bound. If it was looking perpendicular to the galactic plane, it wouldn't be seeing nearly as many stars.

Yes. They obviously picked the most fertile part of the sky, probably subject to some operational constraints.

I didnít mention this is my original post but I was thinking that my numbers would be conservative since I wasnít considering likely moons of the exoplanets.



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