Comet 47P/Wirtanen Observing Campaign

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Comet 47P/Wirtanen Observing Campaign

Post by bystander » Sat Dec 15, 2018 7:37 pm

Comet Wirtanen Observing Campaign
University of Maryland

Welcome to the website for the Comet Wirtanen Observing Campaign.

Our intention is to provide a central clearinghouse for basic information regarding comet 46P/Wirtanen (WERE-tuh-nun) and other high profile comets, to encourage and facilitate the acquisition, analysis and interpretation of observations, and to promote collaborations between researchers.

Now that Wirtanen has reached naked eye brightness (at least at dark sites), one popular question is "Where do I need to look to see it?" Because of the close approach, the comet is rapidly moving from South to North and changes its position from day to day. So the best way to figure out where to look is to use our star charts to guide you in using star patterns to find the comet. On the day of close approach, it is only a few degrees from the Pleiades star cluster, which makes a nice pointer.

We've had a lot of images submitted by observers from all over the world. If you have cloudy skies (or just want to see some great pictures), check them out: AOP Wirtanen Gallery. Images are also available at the Spaceweather.com Gallery or at a number of facebook sites.

Watch comet 46P/Wirtanen as it nears Earth
University of Wisconsin | 2018 Dec 13

LCO Builds New Instrument to Study December Comet
Las Cumbres Observatory | 2018 Dec 14

See a Passing Comet This Sunday
NASA | JPL-Caltech | 2018 Dec 14
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ALMA Gives Christmas Comet Its Close-up

Post by bystander » Thu Dec 20, 2018 7:37 pm

ALMA Gives Christmas Comet Its Close-up
ALMA | NRAO | NAOJ | ESO | 2018 Dec 20
As comet 46P/Wirtanen neared Earth on December 2, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) took a remarkably close look at its innermost regions. ALMA imaged the comet when it was approximately 16.5 million kilometers from Earth. At its closet on December 16, the comet – one of the brightest in years — was approximately 11.4 million kilometers from Earth, or 30 times the distance from the Earth to the moon. ...

The ALMA image of comet 46P/Wirtanen zooms-in to very near its nucleus – the solid “dirty snowball” of the comet itself — to image the natural millimeter-wavelength “glow” emitted by molecules of hydrogen cyanide (HCN), a simple organic molecule that forms an ethereal atmosphere around the comet. ALMA, using its remarkable ability to see fine details, was able to detect and image the fine-scale distribution of this particular molecule.

The HCN image shows a compact region of gas and an extended, diffuse, and somewhat asymmetrical, pattern in the inner portion of the coma. Due to the extreme proximity of this comet, most of the extended coma is resolved out, so these observations are only sensitive to the innermost regions, in the immediate vicinity of the nucleus. ...
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Keck: Comet Hunters Successfully Observe Wirtanen

Post by bystander » Thu Dec 20, 2018 7:46 pm

Comet Hunters Successfully Observe Wirtanen
W.M. Keck Observatory | NIRSPEC | 2018 Dec 19
NIRSPEC Upgrade Delivers Sharper Views of Comet Wirtanen

Astronomers are being treated to an exciting view of Comet 46P/Wirtanen at W. M. Keck Observatory, with sharper-than-ever data images of this icy and rocky space visitor.

A group of comet scientists led by Boncho Bonev, Physics Research Assistant Professor at American University, just completed their two-night observation of the comet as it made its long-anticipated closest approach to Earth.

“It is very exciting because the comet is so close and sufficiently bright for detailed astronomical studies,” said Bonev. “Comet Wirtanen is only 30 lunar distances from our planet, meaning that it is about 30 times the distance to the moon. That is nothing compared to the vast distances astronomers typically work with.”

NASA awarded Bonev’s team telescope time on Sunday and Monday, December 16-17, at Keck Observatory to study Comet Wirtanen. The researchers used the Observatory’s Near-Infrared Spectrograph (NIRSPEC) for the first time on a comet since this powerful instrument’s recent major upgrade. ...
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Re: ALMA Gives Christmas Comet Its Close-up

Post by neufer » Thu Dec 20, 2018 9:26 pm

https://en.wikipedia.org/wiki/Hydrogen_cyanide wrote:
Click to play embedded YouTube video.
:arrow: Hydrogen cyanide (HCN) is a colorless, extremely poisonous and flammable liquid that boils slightly above room temperature. HCN has a faint bitter almond-like odor. Cyanide ions interfere with iron-containing respiratory enzymes. Under the name prussic acid, HCN has been used as a killing agent in whaling harpoons, although it proved quite dangerous to the crew deploying it, and thus it was quickly abandoned. On 11 August 2014, astronomers released studies, using the Atacama Large Millimeter /Submillimeter Array (ALMA) for the first time, that detailed the distribution of HCN, HNC, H2CO, and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON). In February 2016, it was announced that traces of hydrogen cyanide were found in the atmosphere of the hot Super-Earth 55 Cancri e with NASA's Hubble Space Telescope. It has been postulated that carbon from a cascade of asteroids (known as the Late Heavy Bombardment), resulting from interaction of Jupiter and Saturn, blasted the surface of young Earth and reacted with nitrogen in Earth's atmosphere to form HCN.

HCN has been detected in the interstellar medium and in the atmospheres of carbon stars. Since then, extensive studies have probed formation and destruction pathways of HCN in various environments and examined its use as a tracer for a variety of astronomical species and processes. HCN can be observed from ground-based telescopes through a number of atmospheric windows. HCN is formed in interstellar clouds through one of two major pathways: via a neutral-neutral reaction (CH2 + N → HCN + H) and via dissociative recombination (HCNH+ + e → HCN + H). HCN has been used to analyze a variety of species and processes in the interstellar medium. It has been suggested as a tracer for dense molecular gas and as a tracer of stellar inflow in high-mass star-forming regions. Further, the HNC/HCN ratio has been shown to be an excellent method for distinguishing between Photodissociation and X-ray-dominated regions.>>
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NASA Telescopes Take a Close Look at Comet 46P/Wirtanen

Post by bystander » Fri Dec 21, 2018 6:12 pm

NASA Telescopes Take a Close Look at the Brightest Comet of 2018
NASA | GSFC | 2018 Dec 20

As the brilliant comet 46P/Wirtanen streaked across the sky, NASA telescopes caught it on camera from multiple angles.

NASA’s Hubble Space Telescope photographed comet 46P/Wirtanen on Dec. 13, when the comet was 7.4 million miles (12 million kilometers) from Earth. In this visible-light image, the comet’s nucleus is hidden in the center of a fuzzy glow from the comet’s coma. The coma is a cloud of gas and dust that the comet has ejected during its pass through the inner solar system due to heating from the Sun. To make this composite image, the color blue was applied to high-resolution grayscale exposures acquired from the spacecraft’s Wide Field Camera 3 (WFC3) instrument.

The inner part of a comet’s coma is normally not accessible from Earth. The close flyby of comet 46P/Wirtanen allowed astronomers to study it in detail. They combined the unique capabilities of Hubble, NASA’s Chandra X-ray Observatory and the Neil Gehrels Swift Observatory to study how gases are released from the nucleus, what the comet’s ices are composed of, and how gas in the coma is chemically altered by sunlight and solar radiation.
NASA’s Stratospheric Observatory for Infrared Astronomy, SOFIA, took this image of the comet on Dec. 16 and 17 when the aircraft was flying at 40,000 feet:

Comets and asteroids may be the source of Earth’s water. SOFIA is studying the chemical fingerprints of different types of hydrogen in the comet’s water, which will help us learn about the origins and history of water in the solar system — including Earth’s oceans.

The SOFIA image was taken with the telescope's visible-light guide camera, using an orange filter to indicate the intensity of light relative to other objects. SOFIA's observations using infrared light to study the comet's water are now under analysis. ...
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UA: Rare Radar Images of Comet 46P/Wirtanen

Post by bystander » Sun Dec 23, 2018 4:18 pm

UA Researcher Captures Rare Radar Images of Comet 46P/Wirtanen
University of Arizona | 2018 Dec 20

A UA-led team took the best known opportunity for the next 30 years to image a comet with radar, resulting in some unique and surprising information about Comet 46P/Wirtanen.

comet46p_15dec18ut_p3f8192s10d2r5[1].gif
This sequence of radar images of Comet 46P/Wirtanen from Dec. 15 shows apparent
rotation of the nucleus in a counter-clockwise direction.The nucleus rotates once
every 8.9 hours. This movie covers 1.4 hours of the comet’s rotation.

Although barely visible to the naked eye, Comet 46P/Wirtanen keeps some secrets so close that only radar can uncover them.

As the comet was making its close approach to Earth on Dec. 16, it was studied by a team of scientists led by Ellen Howell from the UA's Lunar and Planetary Laboratory. The team used Arecibo Observatory’s planetary radar, which is supported by NASA’s Near-Earth Object Observations program.

Studying the comet with radar provides a glimpse of its nucleus, the solid portion of the comet usually hidden inside a cloud of gas and dust that makes up the coma and tail. Radar images also allow for a precise determination of the comet’s orbit, allowing scientists to better predict how the gas and dust emission can alter the orbit.

Arecibo Observatory, a facility of the National Science Foundation operated by the University of Central Florida, is the only radar facility with the sensitivity to acquire images of Comet 46P/Wirtanen’s nucleus during its flyby. The Arecibo radar observations of Comet 46P/Wirtanen began Dec. 10 and continued through Dec. 18.

The radar images of the nucleus revealed an elongated, somewhat lumpy body that is much rougher than others that have been studied. ...
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Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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