NASA | MSFC | SAO | Chandra X-ray Observatory | 2016 Apr 18
[img3="Credits: X-ray: NASA/CXC/Univ. of CT/B.Snios et al,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.
Optical: DSS, Damian Peach (damianpeach.com)"]http://chandra.harvard.edu/photo/2016/comets/comets.jpg[/img3][hr][/hr]
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 (ISON) and C/2011 S4 (PanSTARRS). ...
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. ...
Chandra Observations of Comets C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS) - Bradford Snios et al
- Astrophysical Journal 818(2):199 (2016 Feb 20) DOI: 10.3847/0004-637X/818/2/199
arXiv.org > astro-ph > arXiv:1601.06622 > 25 Jan 2016 (v1), 24 Feb 2016 (v2)