Classifying Exoplanets

link.

A Time Lapse Video of the Installation of the James Webb Space Telescope Mirrors

SETI Institute Google Plus Hangout Discussing Kepler-138b, c & d.

Videos of HL Tauri Forming ExoPlanets in Resonant and Nonresonant Orbits

A recent and famous image from deep space marks the first time we've seen a forming planetary system, according to a study by U of T astrophysicists.

The team, led by Daniel Tamayo from the Centre for Planetary Science at U of T Scarborough and the Canadian Institute for Theoretical Astrophysics, found that circular gaps in a disk of dust and gas swirling around the young star HL Tau are in fact made by forming planets.

"HL Tau likely represents the first image taken of the initial locations of planets during their formation," says Tamayo. "This could be an enormous step forward in our ability to understand how planets form."

The image of HL Tau, taken in October 2014 by the state-of-the-art Atacama Large Millimeter/submillimeter Array (ALMA) located in Chile's Atacama Desert, sparked a flurry of scientific debate.

While those who observed the original image claimed that planets were most likely responsible for carving the gaps, some remained skeptical. It had been suggested that the gaps, especially the outer three, could not represent forming planets because they are so close together. It was argued that planets massive enough to carve such gaps should be scattered violently by the force of gravity and ejected from the system early on in its development.

But Tamayo's study is the first to suggest the gaps are evidence of planetary formation because the gaps are separated by amounts consistent with what's called a special resonant configuration. In other words, these planets avoid violent collisions with each other by having specific orbital periods where they miss each other, similar to how Pluto has avoided Neptune for billions of years despite the two orbits crossing one another.

Tamayo created two videos to show how HL Tau would appear in both resonant and non-resonant configurations.

The system can be much more stable in a resonant configuration and it's a natural state for planets in the HL Tau system to migrate to says Tamayo.

The HL Tau system is less than a million years old, about 17.9 billion kilometres in radius and resides 450 light years from Earth in the constellation Taurus.

link.

DIY Setup Detects Exoplanet Around HD 189733

Your DSLR can do much more than just take a few nice portraits or the occasional vacation photos – with some DIY magic you can actually turn it into a device which can detect planets outside our solar system – something that 20 years ago was impossible even with the most sophisticated telescopes.

So how can you achieve this? David Schneider who you can see in the video above was able to use his Canon EOS Rebel XS (a.k.a Canon 1000D) camera. With old manual-focus 300mm Nikon telephoto lens he got from eBay for under a $100 with a $17 adapter

link.

Breaking News: The Weather of WASP-43b as Seen by the Hubble

A team of scientists using the NASA/ESA Hubble Space Telescope have made the most detailed map ever of the temperature of an exoplanet's atmosphere, and traced the amount of water it contains. The planet targeted for both of the investigations was the hot-Jupiter exoplanet WASP-43b.

WASP-43b WASP-43b is a planet the size of Jupiter but with double the mass and an orbit much closer to its parent star than any planet in the Solar System. It has one of the shortest years ever measured for an exoplanet of its size -- lasting just 19 hours.

A team of astronomers working on two companion studies have now created detailed weather maps of WASP-43b. One study mapped the temperature at different layers in the planet's atmosphere, and the other traced the amount and distribution of water vapour within it -- detail is shown in the video created by the team.

"Our observations are the first of their kind in terms of providing a two- dimensional map of the planet's thermal structure," said Kevin Stevenson from University of Chicago, USA, lead author of the thermal map study. "These maps can be used to constrain circulation models that predict how heat is transported from an exoplanet's hot day side to its cool night side."

The planet has different sides for day and night because it is tidally locked, meaning that it keeps one hemisphere facing the star, just as the Moon keeps one face toward Earth. The Hubble observations show that the exoplanet has winds that howl at the speed of sound from a day side that is hot enough to melt iron -- soaring above 1500 degrees Celsius -- to the pitch-black night side that sees temperatures plunge to a comparatively cool 500 degrees Celsius.

To study the atmosphere of WASP-43b the team combined two previous methods of analysing exoplanets for the first time.

By looking at how the parent star's light filtered through the planet's atmosphere -- a technique called transmission spectroscopy -- they determined the water abundance of the atmosphere on the boundary between the day and night hemispheres.

In order to make the map more detailed the team also measured the water abundances and temperatures at different longitudes. To do this they took advantage of the precision and stability of Hubble's instruments to subtract more than 99.95% of the light from the parent star, allowing them to study the light coming from the planet itself -- a technique called emission spectroscopy. By doing this at different points of the planet's orbit around the parent star they could map the atmosphere across its longitude.

"We have been able to observe three complete rotations -- three years for this distant planet -- during a span of just four days," explained Jacob Bean from the University of Chicago, USA, leader of the research project. "This was essential in allowing us to create the first full temperature map for an exoplanet and to probe its atmosphere to find out which elements it held and where."

Finding the proportions of the different elements in planetary atmospheres provides vital clues to understanding how planets formed.

"Because there's no planet with these tortured conditions in the Solar System, characterising the atmosphere of such a bizarre world provides a unique laboratory with which to acquire a better understanding of planet formation and planetary physics," said Nikku Madhusudhan of Cambridge University, UK, co-author of both studies. "In this case the discovery fits well with pre-existing models of how such planets behave."

The team found that WASP-43b reflected very little of its host star's light. An atmosphere like that on Earth, with clouds that reflect most of the sunlight, is not present on WASP-43b, but the team did find water vapour in the planet's atmosphere.

"The planet is so hot that all the water in its atmosphere is vapourised, rather than condensed into the icy clouds we find on Jupiter," said team member Laura Kreidberg of the University of Chicago, lead author of the study mapping water on the planet.

link.

Alien Planets Revealed (NOVA Documentary)

Metalicity may be Related to how Much of the Protoplanetary Disk was Consumed by its Host Star

Sea Surface Temperatures? Or Atmospheric Flow? of a Tidally Locked Water World

Flyby of all Known Exoplenatary Systems

A Starshade to Observe Exoplanets Directly

Beta Pictoris Suspected to Have Sheperd Exoplanet at 160 AU (video)

An international team of astronomers exploring the disk of gas and dust around a nearby star have uncovered a compact cloud of poisonous gas formed by ongoing rapid-fire collisions among a swarm of icy, comet-like bodies. The researchers suggest the comet swarm is either the remnant of a crash between two icy worlds the size of Mars or frozen debris trapped and concentrated by the gravity of an as-yet-unseen planet.

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the researchers mapped millimeter-wavelength light from dust and carbon monoxide (CO) molecules in a disk surrounding the bright star Beta Pictoris. Located about 63 light-years away and only 20 million years old, the star hosts one of the closest, brightest and youngest debris disks known, making it an ideal laboratory for studying the early development of planetary systems.

"Although toxic to us, carbon monoxide is one of many gases found in comets and other icy bodies," said team member Aki Roberge, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md. "In the rough-and-tumble environment around a young star, these objects frequently collide and generate fragments that release dust, icy grains and stored gases."

The ALMA images reveal a vast belt of carbon monoxide located at the fringes of the Beta Pictoris system. Much of the gas is concentrated in a single clump located about 8 billion miles (13 billion kilometers) from the star, or nearly three times the distance between the planet Neptune and the sun. The total amount of CO observed, the scientists say, exceeds 200 million billion tons, equivalent to about one-sixth the mass of Earth's oceans.

The presence of all this gas is a clue that something interesting is going on because ultraviolet starlight breaks up CO molecules in about 100 years, much faster than the main cloud can complete a single orbit around the star. "So unless we are observing Beta Pictoris at a very unusual time, then the carbon monoxide we observed must be continuously replenished," said Bill Dent, a researcher at the Joint ALMA Office in Santiago, Chile, and the lead author of a paper published by Science Express on March 6.

Dent and his team calculate that to offset the destruction of CO molecules around Beta Pictoris, a large comet must be completely destroyed every five minutes. Only an unusually massive and compact swarm of comets could support such an astonishingly high collision rate.

Because we view the disk nearly edge-on, the ALMA data cannot determine whether the carbon monoxide belt has a single concentration of gas or two on opposite sides of the star. Further studies of the gas cloud's orbital motion will clarify the situation, but current evidence favors a two-clump scenario.

In our own solar system, Jupiter's gravity has trapped thousands of asteroids in two groups, one leading and one following the planet as it travels around the sun. A giant planet located in the outer reaches of the Beta Pictoris system likewise could corral comets into a pair of tight, massive swarms.

link.

Kepler's Universe