The object, which orbits the star HD 100546, is only 335 light-years from Earth and appears to be a gas giant. If the findings, published this week in Astrophysical Journal Letters, are confirmed, they could provide evidence for hypotheses about how planets form.

“So far, planet formation has mostly been a topic tackled by computer simulations,” says Sascha Quanz, lead researcher on the project and a scientist at ETH Zurich. “If our discovery is indeed a forming planet, then for the first time scientists will be able to study the planet formation process and the interaction of a forming planet and its natal environment empirically at a very early stage.”

For now, the planet has only been detected by the European Southern Observatory’s (ESO) Very Large Telescope as a blob orbiting within the star’s accretion disc. The research team also detected “structures” in the dust cloud near the object as well as an increased temperature that could be caused by planet formation. Current planet-formation hypotheses hold that planets form from the gas and dust that are left over after a star forms.

“Exoplanet research is one of the most exciting new frontiers in astronomy, and direct imaging of planets is still a new field, greatly benefiting from recent improvements in instruments and data analysis methods,” said Adam Amare, a member of the research team. “In this research we used data analysis techniques developed for cosmological research, showing that cross-fertilisation of ideas between fields can lead to extraordinary progress.”

(Image courtesy ESA)

This week, astronomers revealed that a new system has been found that contains planets smaller than Earth. The new data has been presented in a paper published recently in the journal Nature.

The planets orbit around a star called Kepler-37, located around 210 light-years from our solar system. The smallest of the planest found, known as Kepler-37b, is only one-third the size of Earth – smaller than the planet Mercury and just slightly larger than Earth’s moon. The planet is not presumed to have an atmosphere, and scientists predict that life on the planet isn’t likely.

“Even Kepler can only detect such a tiny world around the brightest stars it observes,” said Jack Lissauer, planetary scientist at NASA‘s Ames Research Center. “The fact we’ve discovered tiny Kepler-37b suggests such little planets are common, and more planetary wonders await as we continue to gather and analyze additional data.”

Two other planets were found in the Kepler-37 system. Kepler-37c orbits further out and is slightly smaller than Venus, or around three-quarters the size of Earth. Kepler-37d is the furthest planet out, and is around twice the size of Earth. Kepler-37 itself is slightly smaller and cooler than the sun.

All three of the planets orbit Kepler-37 at less than than the distance between the sun and Mercury. They each also orbit their star in 40 days or less. The surface temperature of Kepler-37b is estimated to be higher than 800 degrees Fahrenheit.

“We uncovered a planet smaller than any in our solar system orbiting one of the few stars that is both bright and quiet, where signal detection was possible,” said Thomas Barclay, lead author of the paper and a Kepler scientist at the Bay Area Environmental Research Institute. “This discovery shows close-in planets can be smaller, as well as much larger, than planets orbiting our sun.”

(Image courtesy NASA/Ames/JPL-Caltech

“We thought we would have to search vast distances to find an Earth-like planet.,” said Courtney Dressing, lead author of the paper and an astronomer at Harvard University. “Now we realize another Earth is probably in our own backyard, waiting to be spotted.”

The research, to be published published in The Astrophysical Journal, came from data from NASA’s Kepler space telescope. 95 planet candidates orbiting 64 red dwarf stars were analyzed, and three of them were found to be smaller than twice the size of earth and orbiting in their stars’ habitable zone.

“We don’t know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined,” said Natalie Batalha, Kepler mission scientist at NASA’s Ames Research Center.

Though the planets may be similar to Earth in some ways, the nature of a red dwarf system could mean they are very different in others. Since the habitable zone of a red dwarf is closer to those stars than our own, planets within that zone would be more susceptible to solar flares. Also, such planets would likely be very old and tidally locked to their star, leaving one side of the planet in perpetual darkness. Astronomers suggest, however, that a thick atmosphere could counteract these effects, and that such stresses could even help life evolve.

“You don’t need an Earth clone to have life,” said Dressing.

(Image courtesy D. Aguilar/Harvard-Smithsonian Center for Astrophysics)

The ionosphere is the region of electrically charged gas high in a planet’s atmosphere. The shape and density of an ionosphere are determined, in part, by the internal magnetic field of its planet. Earth has a strong internal magnetic field, which makes its ionosphere stable. Venus, on the other hand, does not have an internal magnetic field. Its ionosphere has now been found to be shaped by interactions with solar wind.

The new data was obtained in August 2010, when solar wind density dropped to only 0.1 particles per cubic centimeter for around 18 hours. Researchers were able to use this window to observe Venus’ ionosphere balloon out towards its nightside.

“The teardrop-shaped ionosphere began forming within 30–60 minutes after the normal high pressure solar wind diminished. Over two Earth days, it had stretched to at least two Venus radii into space,” said Yong Wei, lead author of a paper on the new research and a scientist at the Max Planck Institute for Solar System Research.

Before now, researchers had debated how solar wind could affect the way ionospheric plasma moves from one side of Venus to the other. The plasma normally flows from the dayside to the nightside of Venus in a thin channel in the ionosphere. Until now, it was unknown whether in low solar wind conditions the flow would increase due to reduced pressure or decrease due to reduced force pushing plasma through the channel.

“We now finally know that the first effect outweighs the second, and that the ionosphere expands significantly during low solar wind density conditions,” said Markus Fraenz, co-author of the paper.

(Image courtesy ESA)

“We are shocked. This is not what we expected,” said Paul Kalas of the University of California at Berkeley and the SETI Institute in Mountain View, Calif.

Kalas led a team that recalculated Fomalhaut b’s orbit from newer observations made last year using NASA’s Hubble Space Telescope. He and his colleagues say these new findings suggest that there could be other objects in the system that sent the planet on its wild trajectory. Hypotheses include an undiscovered planet that gravitationally ejected Fomalhaut b, or a dwarf planet that collided with it.

“Hot Jupiters get tossed through scattering events, where one planet goes in and one gets thrown out,” said Mark Clampin of NASA‘s Goddard Space Flight Center. “This could be the planet that gets thrown out.”

If Fomalhaut b is in the same plane as the dust belt, it will enter the debris around 2032. Astronomers have also detected irregularities and gaps across the dust belt, suggesting that there are other planets to search for in the Fomalhaut system.

NASA‘s Kepler mission has been discovering exoplanets for years now, and the number of confirmed exoplanets is currently 105. As astronomers dig more deeply into Kepler data, smaller planet candidates and multi-planet systems are becoming less rare. The new group of candidates includes four Earth-like planets that are less than twice the size of Earth and orbit their star in a region where liquid water might exist.

“There is no better way to kick off the start of the Kepler extended mission than to discover more possible outposts on the frontier of potentially life-bearing worlds,” said Christopher Burke, Kepler scientist at the SETI Institute.

The number of exoplanet candidates discovered in Kepler data now sits at 2,740 planets orbiting 2,046 stars – a 20% increase from February 2012. The planet candidates are discovered by Kepler when they transit in front of their star, changing its brightness. The Kepler space telescope measures the brightness of over 150,00 stars looking for changes in their brightness. Three transits are required to declare a potential planet, and candidate data is then analyzed for known errors before follow-up observations can confirm the presence of an exoplanet.

“The analysis of increasingly longer time periods of Kepler data uncovers smaller planets in longer period orbits– orbital periods similar to Earth’s,” said Steve Howell, Kepler mission project scientist at NASA’s Ames Research Center. “It is no longer a question of will we find a true Earth analogue, but a question of when.”

(Image courtesy NASA Ames Research Center/W. Stenzel)

“There are at least 100 billion planets in the galaxy, just our galaxy,” said John Johnson, assistant professor of planetary astronomy at Caltech and coauthor of the new study. “That’s mind-boggling.”

The new study, set to be published in The Astrophysical Journal, looked at the planets orbiting a star named Kepler-32, then compared the system to others discovered by the Kepler space telescope. Astronomers stated that the Kepler-32 planets are representative of a majority of planets in the Milky Way, and serve as a case study for how planets form. Systems similar to Kepler-32 comprise around three-quarters of all the stars in our galaxy, leading researchers to their 100 billion-planet estimate.

“I usually try not to call things ‘Rosetta stones,’ but this is as close to a Rosetta stone as anything I’ve seen,” said Johnson. “It’s like unlocking a language that we’re trying to understand—the language of planet formation.”

The prevalence of Kepler-32-type stars, however, suggests that our own solar system may be quite rare. “It’s just a weirdo,” said Johnson.

Kepler-32 is an M dwarf star that is much cooler than our sun, with around half its mass and radius. The five planets orbiting Kepler-32 also orbit much closer to the star than the planets in our solar system. All of the Kepler-32 planets orbit their star within one-tenth of the distance from the Earth to the sun, or just one-third the distance from Mercury to the sun.

That doesn’t mean Kepler-32′s planets are inhospitable, though. The star’s small size also means its habitable zone, where liquid water can exist, is smaller, and the outermost Kepler-32 planet lies within that zone.

(Image courtesy NASA/JPL-Caltech)

The new research, published today in the journal Nature, shows that the gas streams found around a star named HD 142527 may have been created by giant planets that “guzzle” gas from the outer ring as they grow. The disc around the star is divided into an inner and outer ring. The gap between the two is thought to have been made by newly forming gas giant planets. Astronomers had theorized that streams of dust from outer discs might connect the two rings.

“Astronomers have been predicting that these streams must exist, but this is the first time we’ve been able to see them directly,” said Simon Casassus, an astronomer at the University of Chile who led the research. “Thanks to the new ALMA telescope, we’ve been able to get direct observations to illuminate current theories of how planets are formed!”

The ALMA (Atacama Large Millimeter/submillimeter Array) telescope was able to examine HD142527 in greater detail than ever before, and with less glare from the star. Though the gap between discs was already known of, the diffuse gas and denser streams of gas found between the discs has now been observed. In addition, Astronomers found that the rate at which the gas streams into the inner disc is “just right” to keep the inner disc replenished, feeding the still-forming star.

“We think that there is a giant planet hidden within, and causing, each of these streams,” said Sebastián Pérez, a team member on the research. “The planets grow by capturing some of the gas from the outer disc, but they are really messy eaters: the rest of it overshoots and feeds into the inner disc around the star.”

Though it is theorized that forming gas giants are responsible for the streams, the team was unable to detect such planets directly.

“We searched for the planets themselves with state-of-the-art infrared instruments on other telescopes,” said Casassus. “However, we expect that these forming planets are still deeply embedded in the streams of gas, which are almost opaque. Therefore, there may be little chance of spotting the planets directly.”

(Image courtesy ESO)

The study, published in the journal Astronomy & Astrophysics, estimates that the five planets have masses between two and six times that of Earth. This makes it the lowest-mass planetary system yet discovered. One of the planets, with a mass of about five times that of Earth, lies in the habitable zone of the Tau Ceti system, the smallest planet yet found in the habitable zone of a sun-like star.

The habitable zone of a star is defined as the area around a star where a planet could have liquid water on its surface. Just because a planet lies in the habitable zone of a system doesn’t mean it is Earth-like, however. Both Mars and Venus are within the habitable zone of our solar system, though their atmospheres don’t allow for liquid water.

“We are now glimpsing for the first time the secrets of our nearest companion stars and their previously hidden reservoirs of potentially habitable planets,” said Paul Butler, an astronomer at the Carnegie Institution for Science. “This work presages the time when we will be able to directly see these planets, and search them for water, carbon dioxide, methane, and other signposts of life.”

Astronomers used a new technique to detect the planets, applying “intensive” modeling to data collected from over 6,000 observations of Tau Ceti. The research team was able to find signals half the size of what was previously possible, increasing the sensitivity of small planet searches and discovering Tau Ceti’s satellites.

“We pioneered new data modeling techniques by adding artificial signals to the data and testing our recovery of the signals with a variety of different approaches,” said Mikko Tuomi, who led the team from the University of Hertfordshire. “This significantly improved our noise modeling techniques and increased our sensitivity to find low mass planets.”

Tau Ceti was chosen, say the astronomers, because it was though Tau Ceti had no planets and would be a good benchmark for the new technique. The researchers suggest that due to Tau Ceti’s close proximity, the atmospheres of the newly discovered planets could be analyzed in the near future.

According to the atmosphere of Venus contains over one million times as much sulphur dioxide as Earth’s. The gas is hidden below the thick upper clouds on Venus, and is destroyed by sunlight. Large changes in the sulphur dioxide content of Venus’ atmosphere over the past six years and signs of the gas in the upper clouds of Venus suggest the gas has been supplied recently from somewhere on Venus.

Venus is known to be covered in volcanoes, and the Venus Express has uncovered evidence that they have been active within the last few hundred thousand to millions of years. The question of whether they are currently active is under contention.

“If you see a sulphur dioxide increase in the upper atmosphere, you know that something has brought it up recently because individual molecules are destroyed there by sunlight after just a couple of days,” said Emmanuel Marcq, lead author the paper and a researcher with Laboratoire Atmosphères, Milieux, Observations Spatiales.

However, Venus’ “super-rotating” atmosphere, which circles the planet every four Earth-days, circulates the sulphur dioxide. This makes it difficult to isolate the origin of the gas on the planet.

“A volcanic eruption could act like a piston to blast sulphur dioxide up to these levels, but peculiarities in the circulation of the planet that we don’t yet fully understand could also mix the gas to reproduce the same result,” said Jean-Loup Bertaux, co-author of the paper and principal investigator for the sulfer dioxide-detecting instrument on Venus Express.

(Illustration courtesy ESA/AOES)