Pitch Black: Cosmic Clumps Cast The Darkest Shadows

New Discoveries about Star Formation in the Flame Nebula

Stars are often born in clusters, in giant clouds of gas and dust. Astronomers have studied two star clusters using NASA’s Chandra X-ray Observatory and infrared telescopes and the results show that the simplest ideas for the birth of these clusters cannot work.

This composite image shows one of the clusters, NGC 2024, which is found in the center of the so-called Flame Nebula about 1,400 light years from Earth. In this image, X-rays from Chandra are seen as purple, while infrared data from NASA’s Spitzer Space Telescope are colored red, green, and blue.

A study of NGC 2024 and the Orion Nebula Cluster, another region where many stars are forming, suggest that the stars on the outskirts of these clusters are older than those in the central regions. This is different from what the simplest idea of star formation predicts, where stars are born first in the center of a collapsing cloud of gas and dust when the density is large enough.

Credit: NASA/Spitzer/Chandra

Portraits of birds by Laila Jeffreys

In the garden. Värmland, Sweden (October 23, 2015).

Zeta Ophiuchus

A massive star plowing through the gas and dust floating in space. Zeta Oph is a bruiser, with 20 times the Sun’s mass. It’s an incredibly luminous star, blasting out light at a rate 80,000 times higher than the Sun! Even at its distance of 400 light years or so, it should be one of the brightest stars in the sky … yet it actually appears relatively dim to the eye.

Credit: NASA/Hubble

Largest Batch of Earth-size, Habitable Zone Planets

Our Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system.

Assisted by several ground-based telescopes, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

This is the FIRST time three terrestrial planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure both the masses and the radius for habitable zone Earth-sized planets.

All of these seven planets could have liquid water, key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets. To clarify, exoplanets are planets outside our solar system that orbit a sun-like star.

In this animation, you can see the planets orbiting the star, with the green area representing the famous habitable zone, defined as the range of distance to the star for which an Earth-like planet is the most likely to harbor abundant liquid water on its surface. Planets e, f and g fall in the habitable zone of the star.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them. The mass of the seventh and farthest exoplanet has not yet been estimated.

For comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would be the size of a golf ball.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces.

The sun at the center of this system is classified as an ultra-cool dwarf and is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.

 The planets also are very close to each other. How close? Well, if a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.

The planets may also be tidally-locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong wind blowing from the day side to the night side, and extreme temperature changes.

Because most TRAPPIST-1 planets are likely to be rocky, and they are very close to one another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto, Ganymede – as good comparisons in our solar system. All of these moons are also tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than Jupiter, yet much warmer. 

How Did the Spitzer Space Telescope Detect this System?

Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. Spitzer is uniquely positioned in its orbit to observe enough crossing (aka transits) of the planets in front of the host star to reveal the complex architecture of the system. 

Every time a planet passes by, or transits, a star, it blocks out some light. Spitzer measured the dips in light and based on how big the dip, you can determine the size of the planet. The timing of the transits tells you how long it takes for the planet to orbit the star.

The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will help astronomers plan for follow-up studies using our upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere.

At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like: 

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Drops of a liquid can often join a pool gradually through a process known as the coalescence cascade (top left). In this process, a drop sits atop a pool, separated by a thin air layer. Once that air drains out, contact is made and part of the drop coalesces. Then a smaller daughter droplet rebounds and the process repeats.

A recent study describes a related phenomenon (top right) in which the coalescence cascade is drastically sped up through the use of surfactants. The normal cascade depends strongly on the amount of time it takes for the air layer between the drop and pool to drain. By making the pool a liquid with a much greater surface tension value than the drop, the researchers sped up the air layer’s drainage. The mismatch in surface tension between the drop and pool creates an outward flow on the surface (below) due to the Marangoni effect. As the pool’s liquid moves outward, it drags air with it, thereby draining the separating layer more quickly. The result is still a coalescence cascade but one in which the later stages have no rebound and coalesce quickly. (Image and research credit: S. Shim and H. Stone, source)

Look Up! Perseid Meteor Shower Peaks Aug. 11-12

Asteroid Watch logo. Aug. 2, 2016 Make plans now to stay up late or set the alarm early next week to see a cosmic display of “shooting stars” light up the night sky. Known for it’s fast and bright meteors, the annual Perseid meteor shower is anticipated to be one of the best potential meteor viewing opportunities this year. The Perseids show up every year in August when Earth ventures through trails of debris left behind by an ancient comet. This year, Earth may be in for a closer encounter than usual with the comet trails that result in meteor shower, setting the stage for a spectacular display.

Image above: An outburst of Perseid meteors lights up the sky in August 2009 in this time-lapse image. Stargazers expect a similar outburst during next week’s Perseid meteor shower, which will be visible overnight on Aug. 11 and 12. Image Credits: NASA/JPL. “Forecasters are predicting a Perseid outburst this year with double normal rates on the night of Aug. 11-12,” said Bill Cooke with NASA’s Meteoroid Environments Office in Huntsville, Alabama. “Under perfect conditions, rates could soar to 200 meteors per hour.” An outburst is a meteor shower with more meteors than usual. The last Perseid outburst occurred in 2009. Every Perseid meteor is a tiny piece of the comet Swift-Tuttle, which orbits the sun every 133 years. Each swing through the inner solar system can leave trillions of small particles in its wake. When Earth crosses paths with Swift-Tuttle’s debris, specks of comet-stuff hit Earth’s atmosphere and disintegrate in flashes of light. These meteors are called Perseids because they seem to fly out of the constellation Perseus. Most years, Earth might graze the edge of Swift-Tuttle’s debris stream, where there’s less activity. Occasionally, though, Jupiter’s gravity tugs the huge network of dust trails closer, and Earth plows through closer to the middle, where there’s more material. This may be one of those years. Experts at NASA and elsewhere agree that three or more streams are on a collision course with Earth. “Here’s something to think about. The meteors you’ll see this year are from comet flybys that occurred hundreds if not thousands of years ago,” said Cooke. “And they’ve traveled billions of miles before their kamikaze run into Earth’s atmosphere.” How to Watch the Perseids The best way to see the Perseids is to go outside between midnight and dawn on the morning of Aug. 12. Allow about 45 minutes for your eyes to adjust to the dark. Lie on your back and look straight up. Increased activity may also be seen on Aug. 12-13. For stargazers experiencing cloudy or light-polluted skies, a live broadcast of the Perseid meteor shower will be available via Ustream overnight on Aug. 11-12 and Aug. 13-14, beginning at 10 p.m. EDT.: http://www.ustream.tv/channel/nasa-msfc

Meteor Moment: Viewing Tips.

More about the Perseids Perseid meteors travel at the blistering speed of 132,000 miles per hour (59 kilometers per second). That’s 500 times faster than the fastest car in the world. At that speed, even a smidgen of dust makes a vivid streak of light when it collides with Earth’s atmosphere. Peak temperatures can reach anywhere from 3,000 to 10,000 degrees Fahrenheit as they speed across the sky. The Perseids pose no danger to Earth. Most burn up 50 miles above our planet. But an outburst could mean trouble for spacecraft. About the Meteoroid Environment Office It’s Cooke’s job to help NASA understand and prepare for risks posed by meteoroids. He leads a team of meteor experts in the Meteoroid Environments Office at NASA’s Marshall Space Flight Center. They study meteoroids in space so that NASA can protect our nation’s satellites, spacecraft and even astronauts aboard the International Space Station from these bits of tiny space debris. Related links: Meteors & Meteorites: http://www.nasa.gov/topics/solarsystem/features/watchtheskies/index.html Meteoroid Environments Office: https://www.nasa.gov/offices/meo/home/index.html Image (mentioned), Video, Text, Credits: NASA/Jennifer Harbaugh. Greetings, Orbiter.ch Full article

Solar System: Things to Know This Week

There’s even more to Mars.

1. Batten Down the Hatches

Good news for future astronauts: scientists are closer to being able to predict when global dust storms will strike the Red Planet. The winds there don’t carry nearly the same force that was shown in the movie “The Martian,” but the dust lofted by storms can still wreak havoc on people and machines, as well as reduce available solar energy. Recent studies indicate a big storm may be brewing during the next few months.

+ Get the full forecast

2. Where No Rover Has Gone Before

Our Opportunity Mars rover will drive down an ancient gully that may have been carved by liquid water. Several spacecraft at Mars have observed such channels from a distance, but this will be the first up-close exploration. Opportunity will also, for the first time, enter the interior of Endeavour Crater, where it has worked for the last five years. All this is part of a two-year extended mission that began Oct. 1, the latest in a series of extensions going back to the end of Opportunity’s prime mission in April 2004. Opportunity landed on Mars in January of that year, on a mission planned to last 90 Martian days (92.4 Earth days). More than 12 Earth years later, it’s still rolling.

+ Follow along + See other recent pictures from Endeavour Crater

3. An Uphill Climb

Opportunity isn’t the only NASA Mars rover getting a mission extension. On the other side of the planet, the Curiosity rover is driving and collecting samples amid some of the most scenic landscapes ever visited on Mars. Curiosity’s two-year mission extension also began Oct. 1. It’s driving toward uphill destinations, including a ridge capped with material rich in the iron-oxide mineral hematite, about a mile-and-a-half (two-and-a-half kilometers) ahead. Beyond that, there’s an exposure of clay-rich bedrock. These are key exploration sites on lower Mount Sharp, which is a layered, Mount-Rainier-size mound where Curiosity is investigating evidence of ancient, water-rich environments that contrast with the harsh, dry conditions on the surface of Mars today.

+ Learn more

4. Keep a Sharp Lookout

Meanwhile, the Mars Reconnaissance Orbiter continues its watch on the Red Planet from above. The mission team has just released a massive new collection of super-high-resolution images of the Martian surface.

+ Take a look

5. 20/20 Vision for the 2020 Rover

In the year 2020, Opportunity and Curiosity will be joined by a new mobile laboratory on Mars. In the past week, we tested new “eyes” for that mission. The Mars 2020 rover’s Lander Vision System helped guide the rocket to a precise landing at a predesignated target. The system can direct the craft toward a safe landing at its primary target site or divert touchdown toward better terrain if there are hazards in the approaching target area.

+ Get details

Discover the full list of 10 things to know about our solar system this week HERE.

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