Category Archives: Astronomy

Asteroids & Comets, Astronomy, Space participation

Join search for unknown objects in and beyond our own solar system

NASA is sponsoring a new citizen-scientist project hosted at Zooniverse called  Backyard Worlds: Planet 9:

NASA-funded Website Lets the Public Search for New Nearby Worlds 

This artist’s concept illustrates a close-up view of a cool brown dwarf. Objects like this, drifting just beyond our solar system, have been imaged by NASA’s Wide-field Infrared Survey Explorer and could be discovered by Backyard Worlds: Planet 9. Credit: NASA/JPL-Caltech › Full image and caption

NASA is inviting the public to help search for possible undiscovered worlds in the outer reaches of our solar system and in neighboring interstellar space. A new website, called Backyard Worlds: Planet 9, lets everyone participate in the search by viewing brief movies made from images captured by NASA’s Wide-field Infrared Survey Explorer (WISE) mission. The movies highlight objects that have gradually moved across the sky.

“There are just over four light-years between Neptune and Proxima Centauri, the nearest star, and much of this vast territory is unexplored,” said lead researcher Marc Kuchner, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Because there’s so little sunlight, even large objects in that region barely shine in visible light. But by looking in the infrared, WISE may have imaged objects we otherwise would have missed.”

WISE scanned the entire sky between 2010 and 2011, producing the most comprehensive survey at mid-infrared wavelengths currently available. With the completion of its primary mission, WISE was shut down in 2011. It was then reactivated in 2013 and given a new mission assisting NASA’s efforts to identify potentially hazardous near-Earth objects (NEOs), which are asteroids and comets on orbits that bring them into the vicinity of Earth’s orbit. The mission was renamed the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE).

The new website uses the data to search for unknown objects in and beyond our own solar system. In 2016, astronomers at Caltech, in Pasadena, California, showed that several distant solar system objects possessed orbital features indicating they were affected by the gravity of an as-yet-undetected planet, which the researchers nicknamed “Planet Nine.” If Planet Nine — also known as Planet X — exists and is as bright as some predictions, it could show up in WISE data.

The search also may discover more-distant objects like brown dwarfs, sometimes called failed stars, in nearby interstellar space.

“Brown dwarfs form like stars but evolve like planets, and the coldest ones are much like Jupiter,” said team member Jackie Faherty, an astronomer at the American Museum of Natural History in New York. “By using Backyard Worlds: Planet 9, the public can help us discover more of these strange rogue worlds.”

Unlike more distant objects, those in or closer to the solar system appear to move across the sky at different rates. The best way to discover them is through a systematic search of moving objects in WISE images. While parts of this search can be done by computers, machines are often overwhelmed by image artifacts, especially in crowded parts of the sky. These include brightness spikes associated with star images and blurry blobs caused by light scattered inside WISE’s instruments.

Backyard Worlds: Planet 9 relies on human eyes because we easily recognize the important moving objects while ignoring the artifacts. It’s a 21st-century version of the technique astronomer Clyde Tombaugh used to find Pluto in 1930, a discovery made 87 years ago this week.

On the website, people around the world can work their way through millions of “flipbooks,” which are brief animations showing how small patches of the sky changed over several years. Moving objects flagged by participants will be prioritized by the science team for follow-up observations by professional astronomers. Participants will share credit for their discoveries in any scientific publications that result from the project.

“Backyard Worlds: Planet 9 has the potential to unlock once-in-a-century discoveries, and it’s exciting to think they could be spotted first by a citizen scientist,” said team member Aaron Meisner, a postdoctoral researcher at the University of California, Berkeley, who specializes in analyzing WISE images.

Backyard Worlds: Planet 9 is a collaboration among NASA, UC Berkeley, the American Museum of Natural History in New York, Arizona State University in Tempe, the Space Telescope Science Institute in Baltimore, and Zooniverse, a collaboration of scientists, software developers and educators who collectively develop and manage citizen science projects on the internet.

A previously cataloged brown dwarf named WISE 0855?0714 shows up as a moving orange dot in this loop of WISE images spanning five years. By viewing movies like this, anyone can help discover more of these objects. Credits: NASA/WISE › Larger view

NASA’s Jet Propulsion Laboratory in Pasadena manages and operates WISE for NASA’s Science Mission Directorate. The WISE mission was selected competitively under NASA’s Explorers Program managed by the agency’s Goddard Space Flight Center. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colorado. Science operations and data processing take place at IPAC at Caltech, which manages JPL for NASA.

For more information about Backyard Worlds: Planet 9, visit: http://backyardworlds.org

For more information about NASA’s WISE mission, visit: http://www.nasa.gov/wise

 

Astronomy, Science and Technology

Video: “How Stars Form” – Christopher McKee

A SETI Institute seminar by Christopher McKee on how stars are made:

Stars are the atoms of the universe. The process by which stars form is at the nexus of astrophysics since they are believed to be responsible for the re-ionization of the universe, they created the heavy elements, they play a central role in the formation and evolution of galaxies, and their formation naturally leads to the formation of planets. Whereas early work on star formation was based on the assumption that it is a quiescent process, it is now believed that turbulence plays a dominant role. In this overview, I shall discuss the evolution of our understanding of how stars form and current ideas about the stellar initial mass function, the rate of star formation, the formation of massive stars, the role of magnetic fields, and the formation of the first stars.

 

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Astronomy

Video: “What’s Up for February 2017” – highlights of the night sky

Here is a preview of night sky highlights for the coming month:

Use Venus and Mars to find the Zodiacal Light, plus two comets and the brightest asteroid. Find more astronomy information and events in your area by visiting https://nightsky.jpl.nasa.gov/ .

See also :

 

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Astronomy

ESO: Celestial Cat meets the Cosmic Lobster

A new report from ESO (European Southern Observatory):

Celestial Cat Meets Cosmic Lobster 

Astronomers have for a long time studied the glowing, cosmic clouds of gas and dust catalogued as NGC 6334 and NGC 6357, this gigantic new image from ESO’s Very Large Telescope Survey Telescope being only the most recent one. With around two billion pixels this is one of the largest images ever released by ESO. The evocative shapes of the clouds have led to their memorable names: the Cat’s Paw Nebula and the Lobster Nebula, respectively.

This spectacular image from the VLT Survey Telescope shows the Cat’s Paw Nebula (NGC 6334, upper right) and the Lobster Nebula (NGC 6357, lower left). These dramatic objects are regions of active star formation where the hot young stars are causing the surrounding hydrogen gas to glow red. The very rich field of view also includes dark clouds of dust. With around two billion pixels this is one of the largest images ever released by ESO. [Larger views.]
NGC 6334 is located about 5500 light-years away from Earth, while NGC 6357 is more remote, at a distance of 8000 light-years. Both are in the constellation of Scorpius (The Scorpion), near the tip of its stinging tail.

A new image from ESO’s VLT Survey Telescope gives a very detailed view of the star formation regions NGC 6334 and NGC 6357, often called the Cat’s Paw Nebula and the Lobster Nebula, respectively, because of their distinctive shapes. This ESOcast Light takes a quick look at this spectacular vista and explains what it shows. The video is available in 4K UHD.

The British scientist John Herschel first saw traces of the two objects, on consecutive nights in June 1837, during his three-year expedition to the Cape of Good Hope in South Africa. At the time, the limited telescopic power available to Herschel, who was observing visually, only allowed him to document the brightest “toepad” of the Cat’s Paw Nebula. It was to be many decades before the true shapes of the nebulae became apparent in photographs — and their popular names coined.

This montage shows a few of the highlights from a spectacular image from the VLT Survey Telescope showing the Cat’s Paw Nebula (NGC 6334) and the Lobster Nebula (NGC 6357). This part of the sky contains active regions of star formation where hot young stars make their surrounding clouds of hydrogen glow with a characteristic red colour. There are also clouds of dark dust in this rich celestial landscape. [Larger views]
The three toepads visible to modern telescopes, as well as the claw-like regions in the nearby Lobster Nebula, are actually regions of gas — predominantly hydrogen — energised by the light of brilliant newborn stars. With masses around 10 times that of the Sun, these hot stars radiate intense ultraviolet light. When this light encounters hydrogen atoms still lingering in the stellar nursery that produced the stars, the atoms become ionised. Accordingly, the vast, cloud-like objects that glow with this light from hydrogen (and other) atoms are known as emission nebulae.

This video sequence takes the viewer deep into the bright constellation of Scorpius (The Scorpion) and finishes on a new and very detailed view of the star formation regions NGC 6334 and NGC 6357, known as the Cat’s Paw and Lobster Nebulae respectively. Credit: ESO/N. Risinger (skysurvey.org). Music: Nuclearmetal

Thanks to the power of the 256-megapixel OmegaCAM camera, this new Very Large Telescope Survey Telescope (VST) image reveals tendrils of light-obscuring dust rippling throughout the two nebulae. At 49511 x 39136 pixels this is one of the largest images ever released by ESO.

OmegaCAM is a successor to ESO’s celebrated Wide Field Imager (WFI), currently installed at the MPG/ESO 2.2-metre telescope on La Silla. The WFI was used to photograph the Cat’s Paw Nebula in 2010, also in visible light but with a filter that allowed the glow of hydrogen to shine through more clearly (eso1003). Meanwhile, ESO’s Very Large Telescope has taken a deep look into the Lobster Nebula, capturing the many hot, bright stars that influence the object’s colour and shape (eso1226).

This video sequence takes a close look at a spectacular image from the VLT Survey Telescope. It shows the Cat’s Paw Nebula (NGC 6334) and the Lobster Nebula (NGC 6357). These are regions of active star formation where the hot young stars are causing the surrounding hydrogen gas to glow red. The very rich field of view also includes dark clouds of dust. Credit: ESO/N. Bartmann. Music credit: Johan B. Monell

Despite the cutting-edge instruments used to observe these phenomena, the dust in these nebulae is so thick that much of their content remains hidden to us. The Cat’s Paw Nebula is one of the most active stellar nurseries in the night sky, nurturing thousands of young, hot stars whose visible light is unable to reach us. However, by observing at infrared wavelengths, telescopes such as ESO’s VISTA can peer through the dust and reveal the star formation activity within.

Viewing nebulae in different wavelengths (colours) of light gives rise to different visual comparisons on the part of human observers. When seen in longer wavelength infrared light, for example, one portion of NGC 6357 resembles a dove, and the other a skull; it has therefore acquired the additional name of the War and Peace Nebula.

This chart of the bright constellation of Scorpius (The Scorpion) shows the stars visible to the unaided eye on a clear and dark night. It covers a rich part of the sky that is host to many star clusters, glowing clouds of gas and dark dust clouds. Two star formation regions, NGC 6334 (the Cat’s Paw Nebula) and NGC 6357 (the Lobster Nebula) are marked with red circles. Although these clouds appear spectacular in pictures they are very faint and hard to see visually, even with a large telescope. Credit: ESO [Larger versions]
More information

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

 

Asteroids & Comets, Astronomy

Video: Exocomets – “Now you see them, now you don’t”

Thousands of exoplanets around other stars have now been detected (mostly indirectly) in the past couple of decades. Now exocomets at other stars have also been detected. Here is a SETI Seminar about these distant dirty snowballs:

From the caption:

Present technology does not enable us to view images of these kilometer-sized infalling bodies, but the evaporation of gaseous products liberated from exocomets that occurs close to a star can potentially cause small disruptions in the ambient circumstellar disk plasma. For circumstellar disks that are viewed “edge-on” this evaporating material may be directly observed through transient (night-to-night and hour-to-hour) gas absorption features seen at rapidly changing velocities.

Using high resolution spectrographs mounted to large aperture ground-based telescopes, we have discovered 15 young stars that harbor swarms of exocomets. In this lecture we briefly describe the physical attributes of comets in our own solar system and the instrumental observing techniques to detect the presence of evaporating exocomets present around stars with ages in the 10 – 100 Myr range.

We note that this work has particular relevance to the dramatic fluctuations in the flux recorded towards “Tabby’s star” by the NASA Kepler Mission, that may be explained through the piling up of swarms of exocomets in front of the central star.