Earth-sized exoplanet found only 39 light years away

Worlds without end: Astronomers have discovered an exoplanet only slightly bigger then the Earth, and it’s only 39 light years away.

Berta-Thompson and the others estimate that GJ 1132b has a diameter of about 9,200 miles, slightly bigger than Earth. Its mass, however, is thought to be 60 percent greater than Earth’s. Its home star — GJ 1132 — is a red dwarf one-fifth the size of our sun. The planet circles every 1.6 days from just 1.4 million miles out, thus the heat wave. A slight dip in the starlight every 1.6 days was the giveaway for the observing team. “Our ultimate goal is to find a twin Earth,” said astronomer David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, one of the authors, “but along the way we’ve found a twin Venus.”

Earth might be one of the universe’s first habitable planets

The uncertainty of science: An analysis of data from the Hubble Space Telescope and Kepler suggests that the Earth might be one of the first planets in the universe to harbor life.

I label this result uncertain because it is based on what I consider to be a very poor sampling of exoplanets as seen by Kepler. Kepler might have found a lot of exoplanets, but the numbers are still small and skewed by the limited types of suns observed and the short time frame of its observations. Moreover, the data from Hubble is rich, but also quite small, leaving great uncertainties for all of these conclusions.

At the same time, this conclusion might help explain why, after almost a half century of looking, we have yet to detect any evidence of radio communications from any other civilizations. You would think we would have detected something by now. Maybe they don’t exist, and we are the first.

Astronomers photograph an exoplanet

51 Eridani b

Cool image time! Astronomers have used the Gemini Telescope on Mauna Kea to take the clearest image yet of a Jupiter-sized gas giant orbiting another star 96 light years away.

Once the astronomers zeroed in on the star, they blocked its light and spotted 51 Eri b orbiting a little farther away from its parent star than Saturn does from the sun. The light from the planet is very faint — more than one million times fainter than its star – but GPI can see it clearly. Observations revealed that it is roughly twice the mass of Jupiter. Other directly imaged planets are five times the mass of Jupiter or more. In addition to being the lowest-mass planet ever imaged, it’s also the coldest — about 800 degrees Fahrenheit — and features the strongest atmospheric methane signal on record. Previous Jupiter-like exoplanets have shown only faint traces of methane, far different from the heavy methane atmospheres of the gas giants in our solar system.

All of these characteristics, the researchers say, point to a planet that is very much what models suggest Jupiter was like in its infancy.

The exoplanet is the bright spot near the bottom of the image.

Astronomers confirm existence of Earthlike exoplanet 21 light years away

Worlds without end: Astronomers have confirmed the existence of a rocky Earthlike exoplanet only 21 light years away.

HD 219134b is also the closest exoplanet to Earth to be detected transiting, or crossing in front of, its star and, therefore, perfect for extensive research. “Transiting exoplanets are worth their weight in gold because they can be extensively characterized,” said Michael Werner, the project scientist for the Spitzer mission at NASA’s Jet Propulsion Laboratory in Pasadena, California. “This exoplanet will be one of the most studied for decades to come.”

The planet has a mass 4.5 times that of Earth, and orbits its sun every three days, which means it is not likely to harbor life. Its sun also harbors three other small exoplanets, but little is known of them.

Expect a lot more news coming from HD 219134b, however. With transits every three days, astronomers are going to have a lot of opportunities to study its atmosphere and make-up.

Worlds without end

Last week’s fly-by of Pluto by New Horizons illustrated forcefully once again the power of exploration on the human mind, and how that exploration always carries surprises that delight and invigorate us.

First of all, the images from that fly-by demonstrated clearly that the decision by the International Astronomical Union (IAU) to declare Pluto a non-planet was very much premature. Even project scientist Alan Stern himself enthusiastically noted at the start of Friday press conference that Pluto-Charon was a “double planet system”.

The IAU definition itself was faulty and difficult to apply. The clause that required a planet to have “cleared the neighborhood around its orbit” made little sense in the real universe, as even the Earth has not successfully cleared its orbit after several billion years. Was the IAU suggesting the Earth was not a planet?

New Horizons’s discovery last week that even a small object like Pluto, orbiting the Sun on its own with no gas giant nearby to provide tidal heating, can still exhibit significant and on-going geological activity, shows that our understanding of what defines a planet is at this time quite limited. We simply don’t know enough about planetary evolution and formation to definitively define the term. Nor do we have enough knowledge to determine if Pluto falls into that category, though the data strongly suggests that it does.

Are planets made up of only gas giants, rocky terrestrial planets like the Earth, and dwarf planets like Ceres and Pluto? Or are there numerous other as yet unknown categories?
» Read more

Astronomers confirm Kepler discovery of near twin of Earth

Worlds without end! In the release today of another set of Kepler data, astronomers have announced the discovery in that dataset of a new twin of Earth.

The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone — the area around a star where liquid water could pool on the surface of an orbiting planet — of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030. …

Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. While its mass and composition are not yet determined, previous research suggests that planets the size of Kepler-452b have a good chance of being rocky. While Kepler-452b is larger than Earth, its 385-day orbit is only 5 percent longer. The planet is 5 percent farther from its parent star Kepler-452 than Earth is from the Sun. Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger.

While this exoplanet is certainly not identical to Earth, it is close enough that the possibility of alien life — really alien life — could very likely exist upon it.

The dataset also included 11 other Earth twin candidate exoplanets that still need to be confirmed.

Astronomers find exoplanet twin of Jupiter

Worlds without end: Astronomers have discovered an exoplanet with the same mass as Jupiter orbiting its star in a very similar orbit.

Not only that, but:

The planet’s host, the solar twin HIP 11915, is not only similar in mass to the Sun, but is also about the same age. To further strengthen the similarities, the composition of the star is similar to the Sun’s. The chemical signature of our Sun may be partly marked by the presence of rocky planets in the Solar System, hinting at the possibility of rocky planets also around HIP 11915.

I immediately wonder if this star also has rocky inner planets.

Astronomers have discovered an exoplanet smaller than Earth

Worlds without end: Scientists have measured the size and mass of the smallest exoplanet yet, a Mars-sized planet orbiting a star about 200 light years away.

The planet, named Kepler-138 b, is the first exoplanet smaller than the Earth to have both its mass and its size measured. It is one of three planets that orbit the star Kepler-138 and that pass in front of it on every orbit as viewed from Earth — a maneuver that astronomers call a transit. “Each time a planet transits the star, it blocks a small fraction of the star’s light, allowing us to measure the size of the planet,” said Dr. Daniel Jontof-Hutter, a research associate in astronomy at Penn State who led the study.

“We also measured the gravity of all three planets, using data from NASA’s Kepler mission, by precisely observing the times of each transit,” Jontof-Hutter said. The astronomers also were able to measure the masses of these planets. “Each planet periodically slows down and accelerates ever so slightly from the gravity of its neighboring planets. This slight change in time between transits allowed us to measure the masses of the planets,” Jontof-Hutter explained. After measuring both the mass and size of an exoplanet, astronomers then can calculate its density and its bulk composition.

A solar system like our own, but when it was a baby

Astronomers have discovered a very young 15 million year old star only 360 light years away that has a debris disk about the size of our solar system’s Kuiper Belt.

The ring is about the same distance from its parent star as the Kuiper belt is from the Sun, and receives roughly the same amount of light. Its blue-grey colour hints that it could consist of ices and rocky silicates such as those found in the Kuiper belt, says lead author Thayne Currie, an astronomer at the Subaru Telescope in Hawaii, which is run by the National Astronomical Observatory of Japan. “This is absolutely the closest example we have of a young Kuiper belt,” he says.

The best part of this discovery however might be how it was made, by using a new instrument on the ground-based Gemini telescope on Mauna Kea in Hawaii.

The instrument, which is part of the Gemini South telescope in Chile, uses a disk called a coronagraph to blot out the glare of bright stars. That allows it to take multi-wavelength pictures of faint, orbiting planets and debris disks around stars, by recording near-infrared light from the parent star as it scatters off the debris. The researchers discovered the disk around HD 115600 fewer than 6 months after the GPI began operation. A similar instrument, known as SPHERE, began operating in May 2014 on the European Southern Observatory’s Very Large Telescope in Chile and has also begun to make discoveries.

Assuming protesters don’t force Gemini to close, we should be getting a lot more exoplanetary discoveries from it in the coming years.

An exoplanet that shouldn’t exist

Worlds without end: Astronomers have discovered an exoplanet that is too big for its tiny host star.

Present theory says that a Jupiter-sized planet should not have formed around this M-class dwarf star. But it has. In addition, the planet has the mass of Saturn but has been puffed up to the size of Jupiter. Yet, the star doesn’t provide it enough heat to cause it to puff up in this manner.

IAU contest to name 20 exoplanets moves forward

Under pressure from many circles to open up its processes for naming objects in space, the International Astronomical Union (IAU) has started a contest to allow non-profits and “registered clubs” to compete to name 20 exoplanets.

Each organisation can submit one naming proposal, for one ExoWorld only. The number of names that need to be submitted depends on which system is selected. For single- and multiple-planet systems, a name for each planet must be submitted, as well as one for the host star. In the 20 ExoWorlds list, five stars already have common names. Consequently, these five stars cannot be considered for public naming. There are 15 stars and 32 planets (47 objects in total) available for naming. The name of the 20 host stars are explained and personal messages from some discoverers are also available here.

To participate in the contest, clubs and non-profit organisations must first register with the IAU Directory of World Astronomy. The deadline for registrations has been extended to 23:59 UTC on 1 June 2015.

You will note that this contest is not open to the public, but to clubs and organizations that the IAU approves. This is typical of the IAU, which wants to retain its power to name everything in space. They are thus keeping this whole process close to the vest and tightly controlled.

In the end it won’t matter, as the names will eventually be chosen by those who go there, or by those who make the discoveries. It would be nice, however, if the IAU would simply recognize this fact.

The first reflected light from an exoplanet detected

For the first time scientists have detected directly the reflected light coming from an exoplanet.

Astronomers using the HARPS planet-hunting machine at ESO’s La Silla Observatory in Chile have made the first-ever direct detection of the spectrum of visible light reflected off an exoplanet. These observations also revealed new properties of this famous object, the first exoplanet ever discovered around a normal star: 51 Pegasi b. The result promises an exciting future for this technique, particularly with the advent of next generation instruments, such as ESPRESSO, on the VLT, and future telescopes, such as the E-ELT.

Solar system of ancient Earths found

Worlds without end: Using archived Kepler data astronomers have identified a solar system of five Earth-sized exoplanets, orbiting a red dwarf star about 117 light years from Earth.

The paper describes Kepler-444, a star that’s 25 percent smaller than our sun and is 117 light years from Earth. The star’s five known planets have sizes that fall between Mercury and Venus. Those planets are so close to their star that they complete their orbits in fewer than 10 days. At that distance, they’re all much hotter than Mercury and aren’t habitable.

The important detail from this discovery is that the star is very ancient, more than 11 billion years old, which means these planets are that old as well. In other words, planets began forming the same time as the first stars. Which also means that there has been plenty of time in the universe for other intelligent life to form, besides our own.

More Earthlike exoplanets found

Worlds without end: Using Kepler astronomers have discovered a red dwarf star 150 light years away with three Earth-like exoplanets, one of which is in the habitable zone.

The three planets are 2.1, 1.7 and 1.5 times the size of Earth. The outermost planet, at 1.5 Earth radii, is the smallest of the bunch and orbits far enough from its host star that it receives levels of light from its star similar to those received by Earth from the sun, said UC Berkeley graduate student Erik Petigura, who discovered the planets Jan. 6 while conducting a computer analysis of the Kepler data NASA has made available to astronomers. He calculated that the three planets receive 10.5, 3.2, and 1.4 times the light intensity of Earth. “Most planets we have found to date are scorched. This system is the closest star with lukewarm transiting planets,” Petigura said. “There is a very real possibility that the outermost planet is rocky like Earth, which means this planet could have the right temperature to support liquid water oceans.”

These planets were found by Kepler in its present reconfigured mission, which once again illustrates the incredible effectiveness of an optical telescope in space. If only we were building some.

Travel posters for alien worlds

NASA has produced retro-style travel posters for three alien exoplanets which you can download and print.

The posters are quite cool, which is not surprising, considering that, in the past four decades, the best interplanetary travel that NASA has been able to achieve has been its graphic power-point and pr images. Unfortunately, for NASA actually going there has not been so easy.

More Earthlike exoplanets confirmed

Worlds without end: Astronomers have confirmed from Kepler data the existence of 8 new exoplanets, all capable of having liquid water on their surface, with two more like Earth than any previous discovery.

These findings nearly double the number of known planets in the habitable zone, but researchers are especially excited about two of the new exoplanets: Their size, location, and star type means they could be rocky planets like Earth — which means they could have evolved life as we recognize it.

One of the planets, Kepler-438b, is only 12 percent bigger than Earth in diameter. That means it’s quite likely a rocky planet. Scientists have given it a 70 percent chance. Kepler-442b is a bit bigger at around 33 percent larger than Earth, but still has a 60 percent chance of being rocky.

But while 438b hits the sweet spot in size, 442b has it beat when it comes to distance from the sun. Both planets orbit a small red dwarf star, cooler than Earth’s Sun, but they also orbit more closely. 438b gets 40 percent more light than Earth, which means it has around a 70 percent chance of being able to hold liquid water. But with 66 percent as much light as our own planet, 442b has a 97 percent chance of being in the habitable zone.

The planet debate continues

In a public debate about the scientific definition of a planet, the IAU’s definition, imposed about eight years ago to expressly prevent Pluto from being called one, was soundly defeated when the votes were counted.

Science historian Dr. Owen Gingerich, who chaired the IAU planet definition committee, presented the historical viewpoint. Dr. Gareth Williams, associate director of the Minor Planet Center, presented the IAU’s viewpoint [which is the definition that is presently considered official by scientific bureaucrats]. And Dr. Dimitar Sasselov, director of the Harvard Origins of Life Initiative, presented the exoplanet scientist’s viewpoint.

Gingerich argued that “a planet is a culturally defined word that changes over time,” and that Pluto is a planet. Williams defended the IAU definition, which declares that Pluto is not a planet. And Sasselov defined a planet as “the smallest spherical lump of matter that formed around stars or stellar remnants,” which means Pluto is a planet.

After these experts made their best case, the audience got to vote on what a planet is or isn’t and whether Pluto is in or out. The results are in, with no hanging chads in sight.

According to the audience, Sasselov’s definition won the day, and Pluto IS a planet.

Notice that two of the three debaters considered Pluto a planet even before the vote was taken. Notice also that the first debater, Gingerich, was on the very committee that the IAU had created to come up with a definition and then ignored completely when its definition decided that Pluto was a planet.

In the end, it will be the people who speak the language that will decide, not IAU bureaucrats. This little public relations event and vote tells me that the bureaucrats will lose.

An exoplanet that was once like a star

Astronomers, using WISE data, have discovered a strange exoplanet that is now as cool as a rocky planet, but was once as hot as a red dwarf star.

The current temperature of the object is 100-150 degrees Celsius, intermediate between that of the Earth and Venus. But the object shows evidence of a possible ancient origin, implying that a large change in temperature has taken place. In the past this object would have been as hot as a star for many millions of years.

Called WISE J0304-2705, the object is a member of the recently established “Y dwarf” class – the coolest stellar temperature class yet defined, added to the end of the sequence OBAFGKMLT (for historical reasons this is not in alphabetical order but follows a decline in temperature from O to T). Although its temperature is not far off that of our own world, the object is not like the rocky Earth-like planets and instead is a giant ball of gas like Jupiter.

As cool as this discovery is (no pun intended), I am most enlightened by the information in the second paragraph above. I had not realized that astronomers had added L, T, and Y classes to the low temperature end of their stellar classification system. For those new to astronomy, you remember the sequence of the first seven classes with the phrase “O Be A Fine Girl Kiss Me”. I wonder what how we can amend this phrase to include the L, T, Y, classes?

Exoplanets with no water

The uncertainty of science: Though planet formation theories said they should have water, in looking for water on three exoplanets astronomers were surprised to discover practically none there.

The three planets, known as HD 189733b, HD 209458b, and WASP-12b, are between 60 and 900 light-years away from Earth and were thought to be ideal candidates for detecting water vapor in their atmospheres because of their high temperatures where water turns into a measurable vapor. These so-called “hot Jupiters” are so close to their star they have temperatures between 1,500 and 4,000 degrees Fahrenheit, however, the planets were found to have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories.

“Our water measurement in one of the planets, HD 209458b, is the highest-precision measurement of any chemical compound in a planet outside our solar system, and we can now say with much greater certainty than ever before that we’ve found water in an exoplanet,” said Nikku Madhusudhan of the Institute of Astronomy at the University of Cambridge, England. “However, the low water abundance we have found so far is quite astonishing.” Madhusudhan, who led the research, said that this finding presents a major challenge to exoplanet theory. “It basically opens a whole can of worms in planet formation. We expected all these planets to have lots of water in them. We have to revisit planet formation and migration models of giant planets, especially “hot Jupiters,” and investigate how they’re formed.”

Two exoplanets disappear

The uncertainty of science: Two exoplanets orbiting Gliese 581, both thought to be in the habitable zone, have now been proven to not even exist.

“We’ve proven that some of the controversial signals from Gliese 581 don’t come from two proposed Goldilocks planets, but instead are coming from activity within the star itself masquerading as planets,” lead study author Paul Robertson, an astronomer at Pennsylvania State University in University Park, told Space.com.

This result should serve as a strong reminder: Though it is likely that many if not most of the so far discovered exoplanets are real, it is also likely that many will turn out to be false positives. We won’t have solid real knowledge about them until we can actually get a close look at them, which will require far better telescopes in space, and maybe even interstellar missions to them.

The existence of a Kepler-found earth-sized planet in the habitable zone has been confirmed.

Worlds without end: The existence of a Kepler-found earth-sized planet in the habitable zone has been confirmed.

The newfound planet, called Kepler-186f, was first spotted by NASA’s Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth’s sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say.

In this new work, the Keck and Gemini ground-based telescopes confirmed Kepler’s discovery.

Using archived Kepler data combined with statistical modeling, scientists have proposed the discovery of another 715 exoplanets.

Using archived Kepler data combined with statistical modeling, scientists have proposed the discovery of another 715 exoplanets.

This announcement is neat, but despite the many news stories about it today, it should be taken with a grain of salt. What the scientists have really done is pinpoint 715 stars where further research is likely to produce good exoplanet results. It is not guaranteed, however, that a scientist looking at these stars will actually see an exoplanet.

A renowned astronomer reminds everyone — the public, the astronomy community, and most importantly the press — that the data collected on most exoplanets is far more uncertain than often claimed.

The uncertainty of science: A renowned astronomer reminds everyone — the public, the astronomy community, and most importantly, the press — that the data collected on most exoplanets so far are far more uncertain than is often claimed.

A planet’s atmosphere is the gateway to its identity, including how it was formed, how it developed and whether it can sustain life, stated Adam Burrows, author of the review and a Princeton University professor of astrophysical sciences. But the dominant methods for studying exoplanet atmospheres are not intended for objects as distant, dim and complex as planets trillions of miles from Earth, Burrows said. They were instead designed to study much closer or brighter objects, such as planets in Earth’s solar system and stars.

Nonetheless, scientific reports and the popular media brim with excited depictions of Earth-like planets ripe for hosting life and other conclusions that are based on vague and incomplete data, Burrows wrote in the first in a planned series of essays that examine the current and future study of exoplanets. Despite many trumpeted results, few “hard facts” about exoplanet atmospheres have been collected since the first planet was detected in 1992, and most of these data are of “marginal utility.”

The good news is that the past 20 years of study have brought a new generation of exoplanet researchers to the fore that is establishing new techniques, technologies and theories. As with any relatively new field of study, fully understanding exoplanets will require a lot of time, resources and patience, Burrows said. “Exoplanet research is in a period of productive fermentation that implies we’re doing something new that will indeed mature,” Burrows said. “Our observations just aren’t yet of a quality that is good enough to draw the conclusions we want to draw. “There’s a lot of hype in this subject, a lot of irrational exuberance. Popular media have characterized our understanding as better than it actually is,” he said. “They’ve been able to generate excitement that creates a positive connection between the astrophysics community and the public at large, but it’s important not to hype conclusions too much at this point.” [emphasis mine]

Burrows’ point is absolutely right. Every single story describing the atmosphere or make-up of any particular exoplanet at this point in time is essentially fantasy. The data are too weak or vague, and hardly robust enough to come to any solid conclusions. In fact, this research repeatedly reminds me of the conclusions many scientists drew from the flimsy spectrographic data that was gathered before the space age about the solar system’s planets. When we finally got spacecraft to those planets, we found those conclusions were routinely wrong.

This is not to say that our new knowledge of exoplanets is not exciting or significant. It is both. We just shouldn’t put too much faith in it at this time.

Europe approves its own more advanced version of Kepler to launch in 2024 and hunt for exoplanets across half the sky.

Europe approves its own more advanced version of Kepler to launch in 2024 and hunt for exoplanets across half the sky.

During its six year long planned mission, PLATO will observe one million stars, leading to the likely discovery and characterisation of thousands of new planets circling other stars. PLATO will scan and observe about half the sky, including the brightest and nearest stars.

PLATO consists of an array of 34 individual telescopes mounted on an observing platform in the space probe. The satellite will be positioned at one of the so-called Lagrangian Points , where the gravitational pull of the Sun and the Earth cancel each other out so the satellite will stay at a fixed position in space. Each of the 34 telescopes has an aperture of 12 centimeters. The individual telescopes can be combined in many different modes and bundled together, leading to unprecedented capabilities to simultaneously observe both bright and dim objects. PLATO will be equipped with the largest camera-system sensor ever flown in space, comprising 136 charge-coupled devices (CCDs) that have a combined area of 0.9 square metres.

More here and here.

What I like about this is that this project is essentially putting another optical telescope in space. The more of these we have the more discoveries we will make, as even a tiny optical telescope in the vacuum of space is more productive than a giant ground-based telescope looking through the foggy atmosphere of Earth.

Astronomers have discovered the first exoplanets orbiting a star almost identical to the Sun.

Astronomers have discovered the first exoplanet orbiting a star almost identical to the Sun.

Astronomers have used ESO’s HARPS planet hunter in Chile, along with other telescopes around the world, to discover three planets orbiting stars in the cluster Messier 67. Although more than one thousand planets outside the Solar System are now confirmed, only a handful have been found in star clusters. Remarkably one of these new exoplanets is orbiting a star that is a rare solar twin — a star that is almost identical to the Sun in all respects.

This discovery is interesting in that some astronomers have proposed that our Sun itself was born in M67, the open galactic star cluster where these exoplanets were found. My March 2012 cover story for Sky & Telescope was on this very subject.

Astronomers, using Kepler data, have identified dozens of exoplanets between 1 and 4 times the mass of the Earth.

Worlds without end: Astronomers, using Kepler data, have identified dozens of exoplanets between 1 and 4 times the mass of the Earth.

One of those planets has the same mass as the Earth, but is far less dense.

The significant fact however that came out of the press conference announcing these results is the belief by astronomers that, based on this data, they expect that 1 in 5 solar systems will have an Earth-sized planet.

Scientists think they have found cloudy skies on a nearby super Earth.

Scientists think they have found cloudy skies on two nearby exoplanets.

One planet is a super Earth, while the other is Neptune-sized.

This finding, as fascinating as it is, is also incredibly uncertain. The data suggests clouds, but the data is quite thin. We are barely seeing what’s there. Without doubt, the reality is far more complex — and interesting — than presently theorized.

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