Intensities of the Martian N2 electron‐impact excited dayglow emissions. Issue 11 (7th June 2013)

• Record Type: Journal Article
• Authors: Fox, Jane L.; F. Hać, Nicholas E.
• Is Part Of: Geophysical research letters. Volume 40:Issue 11(2013:Jun.)
• Page Start: 2529
• Page End: 2533
• Publication Date: 2013-06-07
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/grl.50435
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p id="grl50435-para-0001">[1] The first N<sub>2</sub> emissions in the Martian dayglow were detected by the SPICAM UV spectrograph on board the Mars Express spacecraft. Intensities of the (0, 5) and (0, 6) Vegard‐Kaplan bands were found to be about one third of those predicted more than 35 years ago. The Vegard‐Kaplan band system arises from the transition from the lowest N<sub>2</sub> triplet state (<alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg371kk12j" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="block" altimg="urn:x-wiley:grl:media:grl50435:grl50435-math-0001" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>A</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">Σ</mml:mi></mml:mrow><mml:mrow><mml:mi>u</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup><mml:mo>;</mml:mo><mml:msup><mml:mrow><mml:mi>v</mml:mi></mml:mrow><mml:mrow><mml:mi>′</mml:mi></mml:mrow></mml:msup></mml:math></alternatives>) to the electronic ground state (<alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg371kk14n" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="block" altimg="urn:x-wiley:grl:media:grl50435:grl50435-math-0002" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">Σ</mml:mi></mml:mrow><mml:mrow><mml:mi>g</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup><mml:mo>;</mml:mo><mml:msup><mml:mrow><mml:mi>v</mml:mi></mml:mrow><mml:mrow><mml:mo>″</mml:mo></mml:mrow></mml:msup></mml:math></alternatives>). It is excited in the Martian dayglow by direct electron‐impact excitation of the ground N<sub>2</sub>(<italic>X</italic>) state to the <italic>A</italic> state and by excitation to higher triplet states that populate the <italic>A</italic> state by cascading. Using revised data, we compute here updated intensities of several of the bands in the N<sub>2</sub> triplet systems and those involving the <italic>a</italic><sup>1</sup>Π<sub><italic>g</italic></sub> state, the upper state of the Lyman‐Birge‐Hopfield bands. We find that the predicted limb intensities for the (0, 5) and (0, 6) Vegard‐Kaplan bands are consistent with the measured values.</p> </abstract>