Portal:Radiation astronomy/Resource/25
Greens[edit | edit source]
Green objects or emission lines in the green portion of the visible spectrum are the subject of green astronomy.
In the image at right the iron (Fe XIV) green line is followed by doppler imaging to show associated relative coronal plasma velocity towards (-7 km/s side) and away from (+7 km/s side) the large angle spectrometric coronagraph LASCO satellite camera.
"Carroll and McCormack (1972) in Dublin reported complex spectra in the blue and green wavelength regions of both FeH and FeD".[1]
For elongated dust particles in cometary comas an investigation is performed at 535.0 nm (green) and 627.4 nm (red) peak transmission wavelengths of the Rosetta spacecraft's OSIRIS Wide Angle Camera broadband green and red filters, respectively.[2] "In the green, the polarization of the pure silicate composition qualitatively appears a better fit to the shape of the observed polarization curves".[2] "[B]ut they are characterized by a high albedo."[2] The silicates used to model the cometary coma dust are olivene (Mg-rich is green) and the pyroxene, enstatite.[2]
In December 2006, seven papers were published in the scientific journal, Science, discussing initial details of the sample analysis. Among the findings are: a wide range of organic compounds, including two that contain biologically usable nitrogen; indigenous aliphatic hydrocarbons with longer chain lengths than those observed in the diffuse interstellar medium; abundant amorphous silicates in addition to crystalline silicates such as olivine and pyroxene, proving consistency with the mixing of solar system and interstellar matter, previously deduced spectroscopically from ground observations;[3] hydrous silicates and carbonate minerals were found to be absent, suggesting a lack of aqueous processing of the cometary dust; limited pure carbon (CHON) was also found in the samples returned; methylamine and ethylamine was found in the aerogel but was not associated with specific particles.
References[edit | edit source]
- ↑ John G. Phillips, Sumner P. Davis, Bo Lindgren, and Walter J. Balfour (December 1987). "The near-infrared spectrum of the FeH molecule". The Astrophysical Journal Supplement Series 65 (12): 721-78. doi:10.1086/191241.
- ↑ 2.0 2.1 2.2 2.3 I. Bertini, N. Thomas, and C. Barbieri (January 2007). "Modeling of the light scattering properties of cometary dust using fractal aggregates". Astronomy & Astrophysics 461 (1): 351-64. doi:10.1051/0004-6361:20065461. http://www.aanda.org/articles/aa/full/2007/01/aa5461-06/aa5461-06.html. Retrieved 2011-12-08.
- ↑ The building blocks of planets within the `terrestrial' region of protoplanetary disks. nottingham.ac.uk. http://ukads.nottingham.ac.uk/cgi-bin/nph-bib_query?bibcode=2004Natur.432..479V&db_key=AST. Retrieved 2008-03-04.