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Friday, April 21, 2017

LHS 1140b - A Super-Earth in the Habitable Zone

We're getting our first good characterizations of terrestrial exoplanets lately. First, news broke of a possible planet around the nearest star to our Sun, Proxima Centauri. Then, we explored TRAPPIST-1, a mini solar system just 39 light-years away. Now, researchers from the Harvard-Smithsonian Center for Astrophysics announced the discovery today of a possible super-Earth orbiting an M-dwarf star just 34 light-years away. The discovery was published in the April 20th Nature.

An artist’s impression of exoplanet LHS 1140 orbiting a red dwarf star 41 light-years distant. ESO/SpaceEngine.org

LHS 1140b is a tantalizing find. It is cool, red host, LHS 1140, contains only 15% the mass of our Sun and is at least 5 billion years old. The planet passes in front of its star once every 15 days as seen from Earth. Jason Dittman (Harvard-Smithsonian Center for Astrophysics) and the team combined discovery data from the MEarth project with radial-velocity measurements from the High Accuracy Radial velocity Planet Searcher (HARPS) survey.

The high-resolution follow-up observations enabled researchers to calculate the planet's orbital parameters and physical characteristics to a high degree of precision: The super-Earth, containing between 4.8 and 8.5 times Earth's mass, orbits just 0.09 astronomical units from its primary (almost a quarter of the average distance between the Sun and Mercury). The planet spans around 1.4 Earths. Combine its mass and radius and you'll calculate an incredibly dense 12.5 g/cm3 — the planet has more than twice Earth's average density!

Though red dwarfs are often tempestuous flare stars — a strike against life on any orbiting worlds — they're also long-lived and miserly in terms of energy output. These cool stars are expected to shine for trillions of years, longer than the present age of the Universe. That's a plus in that it gives ample time to get the engine of evolution going.

Read Full Source Article at http://www.skyandtelescope.com/astronomy-news/welcome-lhs-1140b-super-earth-habitable-zone/
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Monday, April 17, 2017

Get Ready for the 2017 Solar Eclipse

The Total Solar Eclipse is just about four months from now!

A total solar eclipse occurs when the Moon covers the face of the Sun as seen from Earth. The complete coverage allows us to see the day as if it were night, and it reveals the solar corona's ghostly wisps. The next total solar eclipse will occur this summer on August 21, 2017, and the eclipse path will cross the continental United States.

Solar Eclipse During Totality in 2015. Image by Miloslav Druckmüller, Shadia Habbal, Peter Aniol, Pavel Štarha
Solar Eclipse During Totality in 2015. Image by Miloslav Druckmüller, Shadia Habbal, Peter Aniol, Pavel Štarha

The solar eclipse begins on August 21, 2017, at 16:48:33 Universal Time (UT), when the shadow descends down on the Pacific Ocean and the Moon takes its first small piece out of the Sun. Totality begins at 18:24:11.9 UT.

August 21, 2017, seemed a long way off from when we first starting talking about this event a few years ago, but for the astronomically savvy the clock has been ticking, and there was no time to waste. Between the last couple of years and now we needed to figure out how to ensure a good experience for the estimated 500 million people across North America who will stand in the Moon's shadow that day.

Path of the 2017 Total Solar Eclipse.
Path of the 2017 Total Solar Eclipse.
Most will see only a partial solar eclipse, but tens of millions within a 65-mile-wide track from Oregon to South Carolina will (weather permitting) witness one of Nature's grandest events. In what is being called the "Great American Eclipse", the Moon will completely block the Sun's bright face for up to 2 minutes 42 seconds, turning day into night and making visible the otherwise hidden and always breathtaking solar corona. Please visit NASA's Solar Eclipse page for more information on the best locations to view the solar eclipse.

Observe the Total Solar Eclipse Safely!

You should NEVER look directly at the sun, but there are ways to safely observe an eclipse. If you do plan to observe the August 2017 eclipse, remember: NEVER look directly at the sun without proper eye protection, except when the solar disk is completely occluded (during the brief period of totality); serious and permanent eye damage can result. However, we wouldn't recommend looking toward the sun without proper eye protection during any part of the eclipse.

"Proper eye protection" includes specially made solar filters, eclipse glasses or No. 14 welder's glass. There are also Solar Eclipse Kits for that are available for viewing this rare event. Observing the eclipse can be done without any astronomical equipment by making a pinhole camera or watching shadows cast by trees. (The gaps between leaves act as natural pinholes.)

Below are a few items that will allow you to view the eclipse in a safe manner:


Orion Solar Eclipse Safe Viewing Glasses, 5-Pack 4.30" ID Set of Orion Binocular Solar Filters Orion Solar Eclipse Safe Viewer, 5-pack
Orion Solar Eclipse Safe Viewing Glasses, 5-Pack 4.30 Orion Solar Eclipse Safe Viewer, 5-pack

You may also safely see the eclipse the old-fashioned way by building a Shoebox Pinhole Camera. Finally, if you miss out on the August 2017 event, don't panic as you'll get another chance seven years later. In 2024, a total solar eclipse will darken the skies above Mexico and Texas, up through the Midwest and northeastern U.S.
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Saturday, April 15, 2017

See An Asteroid From Your Backyard

Every week, a handful of new Earth-approaching asteroids are caught in a net of robotic telescopes and join the ranks of nearly 16,000 other fly-by-night space boulders. Among their number is one 2014 JO25, discovered in May 2014 by astronomers at the Catalina Sky Survey (CSS) near Tucson, Arizona.

An artist's view of an Earth-approaching asteroid passing close to our planet. ESA / P.Carril
An artist's view of an Earth-approaching asteroid passing close
to our planet. ESA / P.Carril

Observations made by NASA's NEOWISE mission have pegged the asteroid at roughly 650 meters (2,000 feet) across and twice as reflective as the Moon. That and its orbit are about all we know about this speeding space mountain for the moment.

That should change very soon. Asteroid 2014 JO25 will be making a close approach to Earth on April 19th. Because of its size and proximity, it will be bright enough to spot in a small, backyard telescope and moving fast enough to see in real time.

Closest approach occurs around 12 UT (7 a.m. CDT) April 19th when it zips by at 1.8 million km (fewer than 1.1 million miles) away, or about four times the distance to the Moon. When darkness falls in Europe and Africa that evening, the asteroid will shine at its peak magnitude of +10.7 along the Ursa Minor–Draco border. Several hours later, North American observers can catch it rolling west across Coma Berenices a hair fainter, between magnitude +10.8 and +11.0.

See Full Source Article at http://www.skyandtelescope.com/observing/see-a-potentially-hazardous-asteroid-from-your-backyard/
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