Venus green glow - co-ordinated ground- and space-based measurements
November 13th, 2014
Another bit of Venus research presented yesterday at the DPS 2014 meeting: analysis of the ephemeral green glow caused by Oxygen atoms high above Venus.
High up in the atmosphere of Venus, the carbon dioxide which makes up most of Venus' atmosphere is split into its constituent parts - at first, into carbon monoxide and monatomic oxygen. Excited oxygen atoms decay to a lower energy state and emit green light at a characteristic frequency of 557.7 nm - this is the same process which causes many aurorae on Earth to appear green.
But this process is much more variable on Venus than on Earth - often when astronomers have looked for this emission it is not detectable. Candace Gray, of New Mexico State University, has been chronicling the appearance and disappearance of this green emission on many nights over the last few years, and now has enough data to investigate what is causing this variability.
This research has involved correlation of the green "nightglow" occurrence with solar activity, but also to Venus Express observations. Venus Express instruments have not yet directly observed the green glow, due to its faintness (although not all available measurements have been analysed at this time). However, Venus Express also carries an electron spectrometer as part of the ASPERA instrument, and also measures electron density in the ionosphere using radio ocultation sounding. The DPS presentation is presenting the results of this intercomparison...
More information available here:(earthsky.org ) or at the DPS website (aas.org )
The VEx radio occultation analysis is supported in part by the EuroVenus consortium, and represents an ideal example of the synergy between ground- and space-based observations which motivated the formation of the EuroVenus project.
High up in the atmosphere of Venus, the carbon dioxide which makes up most of Venus' atmosphere is split into its constituent parts - at first, into carbon monoxide and monatomic oxygen. Excited oxygen atoms decay to a lower energy state and emit green light at a characteristic frequency of 557.7 nm - this is the same process which causes many aurorae on Earth to appear green.
But this process is much more variable on Venus than on Earth - often when astronomers have looked for this emission it is not detectable. Candace Gray, of New Mexico State University, has been chronicling the appearance and disappearance of this green emission on many nights over the last few years, and now has enough data to investigate what is causing this variability.
This research has involved correlation of the green "nightglow" occurrence with solar activity, but also to Venus Express observations. Venus Express instruments have not yet directly observed the green glow, due to its faintness (although not all available measurements have been analysed at this time). However, Venus Express also carries an electron spectrometer as part of the ASPERA instrument, and also measures electron density in the ionosphere using radio ocultation sounding. The DPS presentation is presenting the results of this intercomparison...
More information available here:(earthsky.org ) or at the DPS website (aas.org )
The VEx radio occultation analysis is supported in part by the EuroVenus consortium, and represents an ideal example of the synergy between ground- and space-based observations which motivated the formation of the EuroVenus project.