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This tiny solar system packs in seven Earth-size planets

TRAPPIST-1 has a solar system like no other. The tiny, tiny red dwarf is just barely big enough to be considered a star and is, radius-wise, a hair bigger than Jupiter. When it was announced last May there was some excitement: the system had three Earth-sized planets and they might all be habitable.

http://www.trappist.one/

We’re going to have to revise that, though. It has seven planets. The results of an intensive study were published today in Nature.

TRAPPIST-1 is so small that it resembles Jupiter and its planets appear more like the jovian moons when laid out distance-wise. TRAPPIST-1b has an orbital period of just 1.5 days and orbits at 1 percent the distance between the Sun and the Earth. Because TRAPPIST-1 is so small, though, instead of dooming the planet it could give it just a slightly balmier-than-comfortable temperature.

The May 2016 events that led to the initial discovery of the planets actually ended up being somewhat in error. Planets TRAPPIST-1b and TRAPPIST-1c were easily confirmed, but TRAPPIST-1d was not. TRAPPIST-1d had a bizarre, hard to constrain orbit much longer than the other planets, and was believed to potentially have an eccentric orbit.

http://www.astronomy.com/news/2016/05/three-potentially-habitable-worlds-found-around-nearby-ultracool-dwarf-star

But there was no TRAPPIST-1d. Or at least not as it appeared. Two transits were witnessed during the first observing campaign, both believed to be the outermost of the three worlds. But those two transits were actually two distinct events.

“The first transit and the second transit were coming from different planets,” Michaël Gillon, a professor at the University of Leige and lead author of the paper, said. “In fact, the second transit was two planets passing at the same time.”

Like no other

That brings us to five planets. Intensive studies using both the TRAPPIST telescope and NASA’s Spitzer telescope helped refine the orbit of the planets and drew out the presence of two more from the data. TRAPPIST-1b, -1c, -1f, and -1g are all very slightly larger than Earth. -1e is slightly smaller than Earth. -1d and -1h are closer to Mars in size.

While the exact masses and orbital periods aren’t known yet, preliminary results suggest that they may be in resonance. That means that when -1b orbits eight times, -1c completes five orbits, often marked as 8:5. -1c and -1d are in 5:3 resonance; -1d and -1e are in 3:2, as are -1e and -1f. -1f and -1g are in 4:3.

All of them seem to be in the habitable zone of TRAPPIST-1. That means that they could, under the right conditions, sustain surface water, but there’s no proof that any of the planets do. For instance, in our solar system Venus and Mars are in the habitable zone, but both are fairly inhospitable in our present time.

Of the seven, the researchers believe that -1e, -1f, and -1g are the likeliest to be habitable based on where they sit in the solar system.

While seven planets have been confirmed, that’s not all the system may hold in store.

“It is just the beginning for many reasons — there might be more on top of that,” Julien de Wit, a co-author on the paper, says.

Slow your roll

There are other considerations before we declare the planets quite ripe for life, though. M-dwarf stars like TRAPPIST-1 tend to start out very active with high energy flare events. This could strip away the atmosphere of young planets.

At this point, according to co-author Emmanuël Jehin, most comets would have been cleared out of the system and thus unable to replenish the atmospheres. But other forces like volcanism could work to stabilize the atmospheres, strengthening them against the relentless flare events.

M-dwarfs finally settle down after the first 3 billion years or so, though many stellar events still occur. For instance, Proxima Centauri is an active flare star, which could doom its habitable zone planet, Proxima Centauri b, from ever forming complex life. But TRAPPIST-1 is cooler and less active than Proxima.

“If you compare it Proxima Centauri, it’s much less, but if you compare it to the Sun, it’s much more,” Gillon said.

TRAPPIST-1 and its seven (!!!) planets are high on the list of planets to be observed by the James Webb Space Telescope (JWST) after it launches next year. A follow-up telescope to TRAPPIST, SPECULOOS, will be able to find more TRAPPIST-type objects. TRAPPIST itself only looked at 50 ultracool stars for planets, while SPECULOOS will look at tens of thousands.

JWST will monitor transits of worlds in the TRAPPIST stars, hoping to capture a glimmer of their atmospheres. If they seem to be thin and water-dominated, we may indeed be looking at a quite Earth-like planet. Or even three of them. Maybe, just maybe, seven.

“We have seven targets that we can study in great depth, and they can give us a completely new insight into planet formation and stellar history,” de Wit says.

Images:
TRAPPIST-1 system

Credit: NASA/JPL-Caltech and Roen Kelly
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On this 6th feb,1971, Apollo 14 astronaut Alan Shepard became the first person to play golf on the moon. He smuggled a makeshift golf club head onto the spacecraft inside a sock. The first ball he hit veered into a nearby crater, but with a solid second swing, the next ball soared for "miles and miles and miles" in the moon’s microgravity. Here, Shepard stands by the Modular Equipment Transporter, a cart for lugging gear around on the lunar surface. — Hanneke Weitering

Credit : NASA
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ESO’s newest nebula image may be the biggest picture taken

At 49,511 x 39,136 pixels, the image clocks in at 5.4 GB

The European Southern Observatory has taken a picture of two nebula in our galaxy so huge that the file would take up 5.4 gigabytes on your hard drive — and likely crash any computer you try to load it on.

The picture involves two nebula NGC 6334 and NGC 6357. Despite all appearances, they’re quite far away from each other. NGC 6334 is 8,000 light years away from us, while NGC 6357 is 5,500 years away. The nebulae are both in the Scorpius constellation.

In between the nebula, several stars are apparent, as well as the shape of a cat’s paw that gives NGC 6334 its nickname. The objects are 2 degrees apart in the sky, or 120 arc minutes. That means this picture spans roughly four lengths of the Moon in the sky. (NGC 6357 is called the Lobster Nebula or the War and Peace Nebula, depending on who you ask.)

Most North American observers won’t be able to see Scorpius, as it’s a southern constellation. I suppose instead that you’ll have to enjoy this 49,511 x 39,136 pixels image.

About image : Cat's Paw Nebula and Lobster Nebula
Credit : ESO 
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Two stars will merge in 2022 and explode into red fury
Get ready for a big nova event ( Prediction)

This is great news for space fans .Also i'd already posted about Supernova.

“We don’t know if it’s right or wrong, but it’s the first time we can make a prediction,” Molnar says. At 2nd magnitude, it’ll be easy if it see if the prediction was correct.

“You won’t need a telescope in 2022 to tell me if I was wrong or I was right,” he says

In 2022, there will be a spectacular sky show. Two stars will merge into one, pushing out excess gas into an explosion known as a red nova. At magnitude 2, it will be as bright as Polaris in the sky, and just behind Sirius and Vega in brightness. The collision in the constellation of Cygnus will be visible for up to six months.

That’s pretty impressive. What’s more impressive: we’ve never been able to predict a nova before. But Lawrence Molnar, a professor of astronomy and physics at Calvin College, was able to find a pair of oddly behaving stars giving an indication of what might happen.

The objects, termed KIC 9832227, are currently contact binaries. Contact binary refers to two objects that are so close they are currently touching. The object was discovered by Kepler. The expected outcome is a merger between the two stars that will put on quite a show. Because both are low mass stars, the expected temperature is low, with Molnar terming it a “red nova.”

how does Molnar know what will happen? After all, as he puts it, it’s “a very specific prediction that can be tested, and a big explosion.” He and his team First observed in 2008, astronomers were able to watch the light curve as the event unfolded. First, there were a few “booms” in the sky. Then, a spectacular light show unfolded. Using precovery data, astronomers were able to trace back the evolution from 2001 on, giving a big picture of the decade of progression of the event.
see more how two stars merge

https://astrobites.org/2012/08/01/two-stars-merged-and-we-got-to-watch/

How did they know it was a merging star?

“V1309 was (brightening) before the explosion,” Molnar said in a press conference at the 229th meeting of the American Astronomical Society. “It isn’t doing it today. That’s the smoking gun of a merging star.”

Using Kepler data, Molnar found that KIC 9832227 fit the lightcurve of V1309 almost perfectly. All radial velocity measurements seem to indicate a contact binary, and by aligning the light curve to the period in time, he and his team came to the conclusion that the merger would complete in 2022.

About Image : Red Nova
credit : STScI _ Molnar and his team

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" Cassini Begins Saturn Ring Dives, Kicks Off Mission Finale "

NASA's Cassini spacecraft begins a series of daring dives through Saturn's rings Nov. 30, the first step in the probe's "grand finale" investigation of the gas giant planet.

Linda Spilker ( Cassini project scientist at NASA's JPL-- Jet Propulsion Laboratory in California ) said that we have two instruments that can sample particles and gases as we cross the ring plane, so in a sense, Cassini is also 'grazing' on the rings.
This isn't the first time Cassini has broken new ground. Over its 12 years in Saturn's system, the probe has dropped a lander on Saturn's moon Titan, discovering the satellite's methane seas; discovered an underground ocean on the moon Enceladus; and investigated the origins of Saturn's strange, giant hexagonal jet stream.
Cassini will pass through a faint outer ring for a few orbits, and then probe the outer reaches of Saturn's F ring, which marks the boundary of the main ring system. The F ring is about 500 miles (800 kilometers) wide — narrow compared to other rings — and features constantly changing streamers, filaments and dark channels that change over the course of hours, NASA researchers said in the statement.

While there, Cassini will explore the many small moons orbiting within and near the rings (including Pandora, Atlas, Pan and Daphnis), scoop up ring particles and gas to analyze, and build an in-depth scan of the rings' structure.

scientists said -- After the mission phase ends in April, Cassini will begin the "Grand Finale" proper, slinging around the moon Titan to begin 22 dives between Saturn and its rings, and finally turning to dive into the planet's atmosphere on Sept. 15. Researchers will use observations of the planet during this ring-grazing phase of to calculate how close the spacecraft can safely go during its dives before the final plunge.

That final dive will not only keep the spacecraft, running out of fuel, from contaminating Saturn's potentially habitable moons, but it will also provide an unprecedented view of the planet's gravity, composition and atmosphere.

Credit : NASA and JPL Laboratory

about image :
1. shows the different ring segments that surround Saturn. The narrow F ring marks the outer boundary of the main ring system.

2. NASA's Cassini spacecraft has racked up some impressive results during its 12-year mission at Saturn.

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2016-11-26
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" BETTER THAN DREAMING "

ESA astronaut Thomas Pesquet arrived at the International Space Station last Saturday with Soyuz spacecraft commander Oleg Novitsky and NASA astronaut Peggy Whitson. This picture is the first he posted on social media, with the comment: “The International Space Station is amazing: better than in my best dreams. I wish everybody could get the chance to come up here!”

about Image :
The image was taken in the Space Station’s Cupola observatory, one of ESA’s contributions to the orbital outpost. Built in Italy, the module features seven windows that are quadruple-glazed and shutters that can be closed for protection.

Although Thomas is only at the start of his six-month Proxima mission, he has already helped Station commander Shane Kimborough to monitor the robotic arm unberthing the Cygnus supply vessel – the golden panels in the background of this picture are on that craft.

Cupola is used to monitor spacecraft arrivals and departures and to operate the 16 m-long arm. It also offers breathtaking views of our planet.

you can follow Thomas and his mission by through the link
http://thomaspesquet.esa.int/

Credit : ESA / NASA
date: 22/11/2016 at 9.11 AM
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" Deep mysteries lurk below (and even above) Mercury’s surface""
or

How does Mercury exist? The more we learn, the more confusing this little world appears.

Mercury is the unloved planet of our Solar System, a barren rock too small and too near the Sun to be interesting. At least, that’s what we thought until we took a closer look and discovered everything about this plain little planet breaks our initial models for how it formed.

Mercury is a hard planet to observe. It’s so close to the Sun that Earth-based telescopes are easily blinded by the star, and locked in orbital resonance that leaves us peering at the same patch of rocks over and over. Even sending spacecraft to investigate is a problem, with probes speeding up as they fall down the gravitational well towards the Sun. It took looping around Venus for Mariner 10 to slow down and redirect into Mercury flybys in the mid-1970s, and the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe needed to make an even more elaborate dance to slip into orbit in 2011.

The challenges of observing Mercury pair with its apparent simplicity to leave it frequently overlooked in favor of more dynamic planets. It’s slightly larger than Earth’s Moon, so scientists assumed it was another cold, dead, and dull cratered world without much to offer to our understanding of the story of planetary formation.

Mercury’s distinguishing characteristic is that it is unusually dense for its size, so dense that it must have an massive metallic core. The core is dramatically disproportional to those found within other terrestrial planets, over half of the planet’s volume while Earth’s is less than 10%. Scientists theorized that it originally formed as a larger planet similar to the Earth and Venus, and either had a major collision strip it of much of its crust (akin to the theory of how Earth gained its Moon), or that it's close proximity to a younger, hotter Sun boiled the crust and vaporized lighter elements.

During its flybys, Mariner 10 mapped a series of long, tall cliffs called scarps and a series of wrinkled folds. Paired with the knowledge that Mercury has an unusually large core, scientists theorized that the planet’s surface crumpled as the core cooled and condensed over billions of years.

If Mercury truly does have a hot, liquid core and is geologically active today, every time the crust moves to create a new ridge or wrinkle, a quake releases seismic waves propagating through the planet. On Earth, we detect that seismic energy with seismometers, observing the speed and distribution of the waves to map the planet’s interior. Astronauts did the same thing on a smaller scale during the Apollo missions, observing moonquakes to understand what was going on below the surface. Scientist are planning to apply the same trick on Mars, sending a seismometer on NASA’s delayed InSight lander to peer into the interior or Mars. This same idea could work on Mercury, with observations of seismic waves pinning down the true size and structure of the core, and detecting if, like the Earth, it has a warm liquid outer core around a solid interior.


And if we can do that? We’ll be one step closer to understanding how Mercury formed, why it is the way it is today, and what to expect of other rocky planets around distant stars.
for more learning stay tunned with me and this collection .will Let you know soon.
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The ESA - European Space Agency's Rosetta Mission ends with a controlled decent to the surface of comet 67/P Friday, Sept. 30 around 7:20AM EDT.

here is more details about these 2 images .

Image-1

Artist's concept of Rosetta shortly before hitting Comet 67P/Churyumov–Gerasimenko on Sept. 30, 2016
Credits: ESA/ATG MediaLab

image-2

Mosaic of four images taken by Rosetta's navigation camera (NAVCAM) on 19 September 2014 at 28.6 km (17.8 mi) from the centre of comet 67P/Churyumov–Gerasimenko. The images used for this mosaic were taken in sequence as a 2×2 raster over an approximately 20 minute period, meaning that there is some motion of the spacecraft and rotation of the comet between the images. The four individual full-frame images are also available as related images below. Note this mosaic has been rotated by 180 degrees and cropped. The mosaic has been put together using Microsoft ICE. This left a few small regions requiring slight exposure adjustments using Adobe LightRoom. The full image has then been lightly contrast enhanced to bring out the activity without increasing the background noise too much.

Credit: ESA/Rosetta/NAVCAM
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2016-09-29
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Junocam - Short movie of approach to Jupiter created from images captured by Juno's JunoCam
https://www.youtube.com/watch?v=jbempdjx2M8
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