On Monday June 19, NASA held a media briefing to announce the completed catalogue of exoplanets from the Kepler Mission.
The catalogue lists 4,034 exoplanet discoveries, including 219 new finds. Ten of these new worlds are close in size to the Earth and reside within their star’s habitable zone , a location that would permit liquid water on the surface of an Earth-like world.
These ten join roughly 40 other worlds found by Kepler as possible candidates for Earth’s twin. But is the prospect of another Earth really the Kepler legacy?
Teeming with planets
While planets had been discovered around other stars since the early 1990s, the launch of the Kepler Space Telescope in 2009 resulted in them being found in droves. As the numbers increased from tens to thousands of exoplanets, astronomers were able to identify types of planets and speculate on their frequency through our Galaxy; Kepler had given us the ability to do statistics.
Our Solar System suggests there are just two flavours of planet: terrestrial worlds like the Earth with rocky surfaces and thin atmospheres, and gas giants like Jupiter, whose solid cores are buried beneath thousands of kilometres of enveloping gases.
This neat, bimodal picture is taken to pieces in the Kepler Mission catalogue.
The catalogue contents reveal gas giants that orbit their star closer than Mercury, other worlds so hot their surface must be molten magma and planets around binary stars like Luke Skywalker’s fictional home world of Tatooine in the film franchise Star Wars.
But perhaps the most mysterious entries are the so-called super Earths.
How super, really?
Over two-thirds of the planets in the Kepler Mission Catalogue have radii of between 1.1 and four Earths, placing them between Earth and Neptune in size. These super Earths are the most common planet discovered, yet our own Solar System has no analogue to tell us what such worlds might be like.
Are they terrestrial planets with rocky surfaces or mini gas giants with crushing atmospheric pressures? As interest has mounted in the prospect of finding a habitable planet, a key question is whether any of these worlds have a solid surface.
NASA/Ames Research Center/Natalie Batalha/Wendy Stenzel, Author provided
At the media briefing, NASA revealed that the Kepler Mission catalogue had produced a clue. A recent journal paper had spotted a split in the distribution of super-Earth planet sizes.
While planets with radii of around 1.3 Earths and 2.4 Earths are equally common, planets with sizes between 1.5 and two Earth radii are much harder to find. The astronomers speculate that this is the division between giant rocky planets and gaseous mini-Neptunes.
Although this strong divide in the super-Earth population has not previously been observed, its location agrees with the small number of planets we have bulk density measurements for. These density values suggest that planets larger than about 1.6 Earth radii have thick, Neptune-like atmospheres.
But while the Kepler Space Telescope can give us both sizes and locations for exoplanets, it cannot tell us anything about their past or present surface environment. We need theories to explain the different planet types identified within the catalogue.
Explaining super Earths
One possibility for the split in the super-Earth population is that the rocky planets have had their atmospheres stripped by radiation pouring from a star. Alternatively, the rocky worlds may have formed later from the gas-rich planet-forming disc that dispersed before the planets could accrue a thick atmosphere.
We meet a similar problem for the 50 planets found within the habitable zone. Knowing only their size and location is not enough to determine if their surfaces are similar to the Earth.
NASA/Ames/Caltech/University of Hawaii, Author provided
A difference in geology could create a very different atmosphere to our own, or the inability to create protective magnetic fields to shield the planet from sterilising stellar flares. The temperature may even be perfect for liquid water, but the planet entirely dry.
Without being able to probe surfaces, the Kepler telescope was never designed to find a true Earth twin. Rather, the mission catalogue tells us that planets can form around nearly every star and exist in a huge variety of conditions.
The Kepler Mission spanned four years (2009 to 2013), exploring a patch of sky in the Cygnus constellation. In May 2013, the second of the telescope’s four gyroscope-like reaction wheels failed and it was unable to keep a stable position.
But the telescope continues to search the sky near the ecliptic plane (where the zodiac constellations lie), using radiation pressure from the Sun for positioning. This has become the K2 mission and has already found over 500 planets.
The Kepler Mission catalogue told us where to look, now we can begin to uncover what alien worlds are truly like.
CAPE CANAVERAL, Fla. (Reuters) – Astronomers on Monday added 219 candidates to the growing list of planets beyond the solar system, 10 of which may be about the same size and temperature as Earth, boosting the chances for life.
Scientists found the planet candidates in a final batch of NASA’s Kepler Space Telescope observations of 200,000 sample stars in the constellation Cygnus.
The candidates include 10 newly discovered rocky worlds that are properly distanced from their parent stars for water, if it exists, to pool on their surfaces. Scientists believe liquid water is a key ingredient for life.
“An important question for us is, ‘Are we alone?'” Kepler program scientist Mario Perez said in a conference call with reporters. “Maybe Kepler today is telling us indirectly … that we are not alone.”
The National Aeronautics and Space Administration launched the Kepler telescope in 2009 to learn if Earth-like planets are common or rare. With the final analysis of Kepler data in hand, scientists said they will now work on answering that question, a key step in assessing the chance that life exists beyond Earth.
During a four-year mission, Kepler found 2,335 confirmed planets and another 1,699 candidates, bringing its tally to 4,034. That number includes about 50 worlds that may be about the same size and temperature as Earth.
Including other telescope surveys, scientists have confirmed the existence of nearly 3,500 planets beyond the solar system.
Kepler’s data also provided a new way to assess whether a planet has a solid surface, like Earth, or is made mostly of gas, like Neptune. The distinction will help scientists home in on potential Earth-like planets and better the odds for finding life.
The Kepler team found that planets which are about 1.75 times the size of Earth and smaller tend to be rocky, while those two- to 3.5 times the size of Earth become gas-shrouded worlds like Neptune.
“It’s like finding what we thought was a single species of animal is really two different things,” said Benjamin Fulton, a graduate student in astronomy who analyzed the Kepler data.
So far, these planets, which scientists refer to as “super-Earths” and “mini-Neptunes,” have not been found in Earth’s solar system, though scientists are on the hunt for a potential ninth planet far beyond Pluto.
“It is interesting that we don’t have what appears to be the most common type of planet in the galaxy,” Fulton said.
(Reporting by Irene Klotz; Editing by Colleen Jenkins and Lisa Shumaker)
NASA’s Kepler space telescope team has released a mission catalog of planet candidates that introduces 219 new planet candidates, 10 of which are near-Earth size and orbiting in their star’s habitable zone, which is the range of distance from a star where liquid water could pool on the surface of a rocky planet.
This is the most comprehensive and detailed catalog release of candidate exoplanets, which are planets outside our solar system, from Kepler’s first four years of data. It’s also the final catalog from the spacecraft’s view of the patch of sky in the Cygnus constellation.
With the release of this catalog, derived from data publicly available on the NASA Exoplanet Archive, there are now 4,034 planet candidates identified by Kepler. Of which, 2,335 have been verified as exoplanets. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.
Additionally, results using Kepler data suggest two distinct size groupings of small planets. Both results have significant implications for the search for life. The final Kepler catalog will serve as the foundation for more study to determine the prevalence and demographics of planets in the galaxy, while the discovery of the two distinct planetary populations shows that about half the planets we know of in the galaxy either have no surface, or lie beneath a deep, crushing atmosphere – an environment unlikely to host life.
The findings were presented at a news conference Monday at NASA’s Ames Research Center in California’s Silicon Valley.
“The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs – planets with roughly the same size and orbit as Earth,” said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate. “Understanding their frequency in the galaxy will help inform the design of future NASA missions to directly image another Earth.”
The Kepler space telescope hunts for planets by detecting the minuscule drop in a star’s brightness that occurs when a planet crosses in front of it, called a transit.
This is the eighth release of the Kepler candidate catalog, gathered by reprocessing the entire set of data from Kepler’s observations during the first four years of its primary mission. This data will enable scientists to determine what planetary populations – from rocky bodies the size of Earth, to gas giants the size of Jupiter – make up the galaxy’s planetary demographics.
To ensure a lot of planets weren’t missed, the team introduced their own simulated planet transit signals into the data set and determined how many were correctly identified as planets. Then, they added data that appear to come from a planet, but were actually false signals, and checked how often the analysis mistook these for planet candidates. This work told them which types of planets were overcounted and which were undercounted by the Kepler team’s data processing methods.
“This carefully-measured catalog is the foundation for directly answering one of astronomy’s most compelling questions – how many planets like our Earth are in the galaxy?” said Susan Thompson, Kepler research scientist for the SETI Institute in Mountain View, California, and lead author of the catalog study.
One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets. The team found a clean division in the sizes of rocky, Earth-size planets and gaseous planets smaller than Neptune. Few planets were found between those groupings.
Using the W. M. Keck Observatory in Hawaii, the group measured the sizes of 1,300 stars in the Kepler field of view to determine the radii of 2,000 Kepler planets with exquisite precision.
“We like to think of this study as classifying planets in the same way that biologists identify new species of animals,” said Benjamin Fulton, doctoral candidate at the University of Hawaii in Manoa, and lead author of the second study. “Finding two distinct groups of exoplanets is like discovering mammals and lizards make up distinct branches of a family tree.”
It seems that nature commonly makes rocky planets up to about 75 percent bigger than Earth. For reasons scientists don’t yet understand, about half of those planets take on a small amount of hydrogen and helium that dramatically swells their size, allowing them to “jump the gap” and join the population closer to Neptune’s size.
The Kepler spacecraft continues to make observations in new patches of sky in its extended mission, searching for planets and studying a variety of interesting astronomical objects, from distant star clusters to objects such as the TRAPPIST-1 system of seven Earth-size planets, closer to home.
Ames manages the Kepler missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.
Originally published at NASA
A batch of raw data from the TRAPPIST-1 find has been released by NASA’s Kepler. You can find this data in whole below, and on the Kepler website.
The use of this data will enable astronomers on the ground to study the star system in great detail, including the understanding of TRAPPIST-1h, the 7th planet in the system whose properties are not yet fully uncovered.
The raw files are made public straight away to aid astronomers in preparing proposals due this month to use ground-based telescopes to further investigate TRAPPIST-1. These are not the project’s true data products: by late May, the routine pipeline processing of the K2 data will be completed and vetted, and the fully calibrated data made available.
While we recommend that scientists only use the pipeline-processed data products in journal papers, we do encourage our community to share their understanding of the raw data with the public by blogging or tweeting tutorials and analyses. This public TRAPPIST-1 data set offers a unique opportunity to let a wider audience witness the process scientific discovery.
The remainder of this blog post summarizes the caveats associated with the raw data, describes the availability of preliminary Target Pixel Files, and offers a quick-look at the TRAPPIST-1 light curve.
Raw data caveats
The use of the raw, uncalibrated data files requires an intimate understanding of their format and caveats. In particular:
- the raw data are not flat-fielded, bias-subtracted, or smear-corrected;
- cadences of poor quality, e.g. due to thruster firings, are not flagged;
- the data are formatted in a non-standard way and require reformatting.
Moreover, during Campaign 12, a cosmic ray event reset the spacecraft’s onboard software causing a five-day break in science data collection from Feb 1st through Feb 6th. The benign event is the fourth occurrence of a cosmic ray susceptibility since launch in March 2009 and the spacecraft remains healthy and operating nominally otherwise.
Pseudo Target Pixel Files
TRAPPIST-1 was observed using a 11×11 short-cadence mask with EPIC ID 200164267 from Dec 15th, 2016, through Mar 4th, 2017. To help the community explore this target, the Guest Observer Office reformatted the raw data into a pseudo Target Pixel Files using the Kadenza tool.
The files are available for download from Zenodo (DOI 10.5281/zenodo.375796):
- Long cadence: k2-trappist1-unofficial-tpf-long-cadence.fits.gz (2 MB)
- Short cadence: k2-trappist1-unofficial-tpf-short-cadence.fits.gz (45 MB)
Compared to traditional Target Pixel Files, the FLUX values in these files are not corrected for smear or bias, and not all header keywords are populated.
Quick look at TRAPPIST-1
A quick-look lightcurve of the long cadence data for TRAPPIST-1 reveals sinusoidal patterns due to star spots, and at least 6 planets:
The pseudo Target Pixel Files above can also be converted into movies using the k2flix tool, which shows TRAPPIST-1 to be at the center of the target mask:
On Feb. 22, astronomers announced that the ultra-cool dwarf star, TRAPPIST-1, hosts a total of seven Earth-size planets that are likely rocky, a discovery made by NASA’s Spitzer Space Telescope in combination with ground-based telescopes. NASA’s planet-hunting Kepler space telescope also has been observing this star since December 2016. Today these additional data about TRAPPIST-1 from Kepler are available to the scientific community.
During the period of Dec. 15, 2016 to March 4, the Kepler spacecraft, operating as the K2 mission, collected data on the star’s minuscule changes in brightness due to transiting planets. These additional observations are expected to allow astronomers to refine the previous measurements of six planets, pin down the orbital period and mass of the seventh and farthest planet, TRAPPIST-1h, and learn more about the magnetic activity of the host star.
“Scientists and enthusiasts around the world are invested in learning everything they can about these Earth-size worlds,” said Geert Barentsen, K2 research scientist at NASA’s Ames Research Center at Moffett Field, California. “Providing the K2 raw data as quickly as possible was a priority to give investigators an early look so they could best define their follow-up research plans. We’re thrilled that this will also allow the public to witness the process of discovery.”
The release of the raw, uncalibrated data collected will aid astronomers in preparing proposals due this month to use telescopes on Earth next winter to further investigate TRAPPIST-1. By late May, the routine processing of the data will be completed and the fully calibrated data will be made available at the public archive.
The observation period, known as K2 Campaign 12, provides 74 days of monitoring. This is the longest, nearly continuous set of observations of TRAPPIST-1 yet, and provides researchers with an opportunity to further study the gravitational interaction between the seven planets, and search for planets that may remain undiscovered in the system.
TRAPPIST-1 wasn’t always on the radar to study. In fact, the initial coordinates for the patch of sky defined as Campaign 12 were set in Oct. 2015. That was before the planets orbiting TRAPPIST-1 were known to exist, so Kepler would have just missed the region of space that is home to this newfound star system of interest.
But in May 2016, when the discovery of three of TRAPPIST-1’s planets was first announced, the teams at NASA and Ball Aerospace quickly reworked the calculations and rewrote and tested the commands that would be programmed into the spacecraft’s operating system to make a slight pointing adjustment for Campaign 12. By Oct. 2016, Kepler was ready and waiting to begin the study of our intriguing neighbor in the constellation Aquarius.
“We were lucky that the K2 mission was able to observe TRAPPIST-1. The observing field for Campaign 12 was set when the discovery of the first planets orbiting TRAPPIST-1 was announced, and the science community had already submitted proposals for specific targets of interest in that field,” said Michael Haas, science office director for the Kepler and K2 missions at Ames. “The unexpected opportunity to further study the TRAPPIST-1 system was quickly recognized and the agility of the K2 team and science community prevailed once again.”
The added refinements to the previous measurements of the known planets and any additional planets that may be discovered in the K2 data will help astronomers plan for follow-up studies of the neighboring TRAPPIST-1 worlds using NASA’s upcoming James Webb Space Telescope.
During Campaign 12, a cosmic ray event reset the spacecraft’s onboard software causing a five-day break in science data collection. The benign event is the fourth occurrence of cosmic ray susceptibility since launch in March 2009. The spacecraft remains healthy and is operating nominally.
Originally published at NASA
During scheduled contacts on April 7th, mission operators discovered that the Kepler spacecraft was in emergency mode (EM).
Emergency mode is the lowest operational mode for the spacecraft and is fuel intensive. Recovering Kepler from EM is the team’s top priority at the moment,
The mission has declared a “spacecraft emergency” which allows access to the ground-based communications tools at the agency’s Deep Space Network.
At first glance it appears that Kepler entered EM roughly 36 hours ago before orienting to the heart of the milky way for a K2 microlensing observation.
Kepler is nearly 75 million miles from Earth and this makes communicating with the spacecraft difficult. At the speed of light, it takes 13 minutes for a signal to travel from the craft to Earth.
The last regular contact with the spacecraft was on April. 4. At that time, the spacecraft was in good health and operating as expected.
We will provide updates as soon as new information is available.
Researchers have discovered a new star with an outer layer of 99.9 percent pure oxygen making it the most oxygen-rich environment in the known universe.
Compare this with Earth’s 21% oxygen content, and you can see just how interesting this find is. It’s a new type of white dwarf star discovered by Brazilian astronomers the Federal University of Rio Grande do Sul in Brazil. The star owns a daunting name – SDSSJ124043.01+671034.68 – but it’s nicknamed ‘Dox’ for short(pronounced Dee-Awks). The discovery was reported first by the Journal Science.
“This white dwarf was incredibly unexpected.”
“This white dwarf was incredibly unexpected,” says the Kepler team, “And because we had no idea anything like it could even exist, that made it all the more difficult to find.”
Dox is only a little bit bigger than Earth, but is 60 percent the mass of our sun. It was discovered from observations of more than 4.5 million stars collected in the last 15 years in the Sloan Digital Sky Survey.
The painstaiking process was undertaken by a Kepler graduate student named Gustavo Ourique who analyzed a pool of more than 300,00 stars to find the unique white dwarf:
“After a few months he could filter a one or two thousand each day, like reading a book”
H/T: Popular Mechanics
A new paper from David Kipping, an astronomer at Columbia University believes it could.
In this paper David Kipping goes on to explain how a 22W laser could disrupt measurements of the Earth’s orbit around the sun, thus deceiving any potential harmful onlookers.
Kipping and his graduate student Alex Teachey, conclude that it would be remarkably easy to “wipe out” Earth’s signal, or at the least distort it. All you need to do is disrupt the “transit method” most commonly used to identify objects in orbit around stars. The transit method is how we identify most planets today, by looking for dips within the light signals of stars – when believed objects pass by.
“To make it look like the planet is not there at all, you’ve got to get rid of that dip. You’ve got to fill in the missing starlight,” Teachey tells in a video.
Planets can still be detected in other ways, such as the gravitational influence on a star – however the idea behind this technology is that it would act as a deterrent to arousing suspicion, thus hindering the possibility of conducting such gravitational experiments.
The idea of cloaking ourselves from aliens could work. However, it needs one specific caveat to make any sense – a universe in which we suspect extra terrestrial life exists, and peering into our daily lives. While that may be entirely true, it’s likely that this theory remains just a fun possibility for astronomers.
A recently released video from NASA’s Ames Research Center shows the “shock breakout” of a star in its supernova phase.
In this illustrated animation you see a red supergiant star 500 times bigger and 20,000 times brighter than our sun. When the star can no longer sustain the nuclear fusion in its core, it collapses under the forces of gravity.
This brings with it a shockwave from the implosion that rushes upward out through the inside of the star’s layers. It breaks through the visible surface of the star in the form of plasma-like jets, and roughly 20 minutes later the star goes full supernova.
The animation is based on the observations made by NASA’s Kepler space telescope closely monitoring the star KSN 2011d with is located 1.2 billion light-years from earth. Kepler caught the early flash, and released this video through Ames to detail the find.