Chandra observations of comets C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS)

Chandra observations of comets C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS)

For millennia, people on Earth have watched comets in the sky. Many ancient cultures saw comets as the harbingers of doom, but today scientists know that comets are really frozen balls of dust, gas, and rock and may have been responsible for delivering water to planets like Earth billions of years ago.

While comets are inherently interesting, they can also provide information about other aspects of our Solar System. More specifically, comets can be used as laboratories to study the behavior of the stream of particles flowing away from the Sun, known as the solar wind.

Recently, astronomers announced the results of a study using data collected with NASA's Chandra X-ray Observatory of two comets—C/2012 S1 (also known as "Comet ISON") and C/2011 S4 ("Comet PanSTARRS").

Chandra observed these two comets in 2013 when both were relatively close to Earth, about 90 million and 130 million miles for Comets ISON and PanSTARRS respectively. These comets arrived in the inner Solar System after a long journey from the Oort cloud, an enormous cloud of icy bodies that extends far beyond Pluto's orbit.

The graphics show the two comets in optical images taken by an astrophotographer, Damian Peach, from the ground during the comets' close approach to the sun that have been combined with data from the Digitized Sky Survey to give a larger field of view. (The greenish hue of Comet ISON is attributed to particular gases such as cyanogen, a gas containing carbon and nitrogen, escaping from the comet's nucleus.)

The insets show the X-rays detected by Chandra from each comet. The different shapes of the X-ray emission (purple) from the two comets indicate differences in the solar wind at the times of observation and the atmospheres of each comet. Comet ISON, on one hand, shows a well-developed, parabolic shape, which indicates that the comet had a dense gaseous atmosphere. On the other hand, Comet PanSTARRS has a more diffuse X-ray haze, revealing an atmosphere with less gas and more dust.

Scientists have determined that comets produce X-ray emission when particles in the solar wind strike the atmosphere of the comet. Although most of the particles in the solar wind are hydrogen and helium atoms, the observed X-ray emission is from "heavy" atoms (that is, elements heavier than hydrogen and helium, such as carbon and oxygen). These atoms, which have had most of their electrons stripped away, collide with neutral atoms in the comet's atmosphere. In a process called "charge exchange," an electron is exchanged between one of these , usually hydrogen, and a heavy atom in the solar wind. After such a collision, an X-ray is emitted as the captured electron moves into a tighter orbit.

The Chandra data allowed scientists to estimate the amount of carbon and nitrogen in the solar wind, finding values that agree with those derived independently using other instruments such as NASA's Advanced Composition Explorer (ACE). New measurements of the amount of neon in the solar wind were also obtained.

The detailed model developed to analyze the Chandra data on comets ISON and PanSTARRS demonstrates the value of X-ray observations for deriving the composition of the solar wind. The same techniques can be used, together with Chandra data, to investigate interactions of the with other comets, planets, and the interstellar gas.

A paper describing these results appeared in the February 20th, 2016 issue of The Astrophysical Journal and is available online. The authors are Bradford Snios and Vasili Kharchenko (University of Connecticut), Carey Lisse (Johns Hopkins University), Scott Wolk (Harvard-Smithsonian Center for Astrophysics), Konrad Dennerl (Max Planck Institute for Extraterrestrial Physics) and Michael Combi (University of Michigan).


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More information: Chandra Observations of Comets C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS). lanl.arxiv.org/abs/1601.06622
Journal information: Astrophysical Journal

Citation: Chandra observations of comets C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS) (2016, April 19) retrieved 18 June 2019 from https://phys.org/news/2016-04-chandra-comets-c2012-s1-ison.html
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Apr 19, 2016
In a process called "charge exchange,"

Sounds a bit like electric "woo", but some posters will claim it's a different kind of electrical interaction.

Apr 19, 2016
In a process called "charge exchange,"

Sounds a bit like electric "woo", but some posters will claim it's a different kind of electrical interaction.


Yep, totally different signature. Narrow lines that can actually be linked to the SW heavy ions causing them, such as O6+ etc. Zilch to do with electric woo, as has been known for a long time. If you'd only bother to do a bit of research before posting your usual b*ll*cks, you could save yourself a lot of embarrassment.

ETA: Mind you, it didn't stop the cretins T&T, so we can't really blame you.

Apr 19, 2016
In a process called "charge exchange,"

Sounds a bit like electric "woo", but some posters will claim it's a different kind of electrical interaction.


jonedave has it exactly right, this is exactly the type of interplay between the solar wind and the diffuse atmosphere surrounding the comets that has been seen and broadly explained (meaning understood dumdum) since at least the close flyby of comet Halley 30 years ago.

Your stupid Prophets of EU got all of that all wrong too Acolyte. All of it. Not one single prediction they made (which have ALL been removed from your Cult site) was correct.

One wonders what it takes to be so able to pretend that 30 years of research haven't happened.

Oh right - faith. Ignore that which conflicts, pretend nothing gets learned, hope no one questions.

Your 40 year old mantra has lost its appeal Acolyte. You should formulate a new strategy.

Apr 19, 2016
In a process called "charge exchange,"

Sounds a bit like electric "woo", but some posters will claim it's a different kind of electrical interaction.


https://www.resea...80a0.pdf

Amongst many others you could have looked at. Amazing how much science is out there, and freely available. For those that can understand it.

Apr 19, 2016
In a process called "charge exchange,"

Sounds a bit like electric "woo", but some posters will claim it's a different kind of electrical interaction.


jonedave has it exactly right, this is exactly the type of interplay between the solar wind and the diffuse atmosphere surrounding the comets that has been seen and broadly explained (meaning understood dumdum) since at least the close flyby of comet Halley 30 years ago.

Your stupid Prophets of EU got all of that all wrong too Acolyte. All of it. Not one single prediction they made (which have ALL been removed from your Cult site) was correct.



To be fair Maggnus, it wasn't discovered until '96 at Hyakutake. Bit of a surprise at the time. Further research revealed what it actually was, based on lab experiments. Narrow line emission. Definitely not electric woo. Otherwise, you are correct :)

Apr 19, 2016
To be fair Maggnus, it wasn't discovered until '96 at Hyakutake. Bit of a surprise at the time. Further research revealed what it actually was, based on lab experiments. Narrow line emission. Definitely not electric woo. Otherwise, you are correct :)


A fair correction, although a part of the reason is was looked for at Hyakutake was because of hints seen at Halley by Giotto (especially) and Sakigake. (See Mendis, 1988 for eg.) They didn't have the instrumentation to call it a discovery. But still, you are correct - so I guess it has "only" been 20 years! :)

Apr 19, 2016
Why am I not surprised, and trust me, I'm not embarrassed. Recall that according to you, ion sputtering isn't actually ion sputtering when a comet is involved, it's a different "ion sputtering". Isn't that correct? Just like this charge exchange isn't really a charge exchange, since a comet is involved it's actually "charge exchange".

Apr 19, 2016
Why am I not surprised, and trust me, I'm not embarrassed. Recall that according to you, ion sputtering isn't actually ion sputtering when a comet is involved, it's a different "ion sputtering". Isn't that correct? Just like this charge exchange isn't really a charge exchange, since a comet is involved it's actually "charge exchange".


You should be embarrassed, you just aren't bright enough to realize it.

He didn't say that dumdum. You should try to comprehend what is said to you instead of automatically deciding it must be wrong, and then misquoting what was said in an effort to score points. Makes you look idiotic.

The normal case is that even a broken clock is right at least once per day. Although, considering your case, you may have just given lie to the adage.

Apr 19, 2016
it wasn't discovered until '96 at Hyakutake. Bit of a surprise at the time.


It was a "bit of a surprise" because there was no mechanism of "sublimating ices" which could explain the presence of X-rays. What they found is it involved "charge exchange" (but clearly not charge exchange that involves any mention of moving charges {in other words electricity}) between the non electric current of the solar wind (the flow of charged particles which isn't really electricity)and the totally inert cometary coma (which through direct in situ measurements has an electric field itself, but forget that because inert is easier) which NON ELECTRICALLY "charge exchanges" E-FUCKING-LECTRONS between the non charged ionized gas (not really plasma apparently) of the solar wind and the not ion sputtered, but "ion sputtered" neutrals in the electrically inert (except for the electric field) coma to create non-EM X-rays.

Yep, any mention of electrical interaction is lunacy.


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