Prof. Patrick Irwin: Publications

Detection of CH$_3$C$_3$N in Titan's Atmosphere

(2020)

Authors:

AE Thelen, MA Cordiner, CA Nixon, V Vuitton, Z Kisiel, SB Charnley, MY Palmer, NA Teanby, PGJ Irwin

Detection of Cyclopropenylidene on Titan with ALMA

The Astronomical Journal American Astronomical Society 160:5 (2020) 205-205

Authors:

Conor A Nixon, Alexander E Thelen, Martin A Cordiner, Zbigniew Kisiel, Steven B Charnley, Edward M Molter, Joseph Serigano, Patrick GJ Irwin, Nicholas A Teanby, Yi-Jehng Kuan

Uranus’ Stratospheric HCl Upper Limit from Herschel/SPIRE* * Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Research Notes of the AAS American Astronomical Society 4:10 (2020) 191

Authors:

NA Teanby, PGJ Irwin

How Does Thermal Scattering Shape the Infrared Spectra of Cloudy Exoplanets? A Theoretical Framework and Consequences for Atmospheric Retrievals in the JWST era

(2020)

Authors:

Jake Taylor, Vivien Parmentier, Michael R Line, Elspeth KH Lee, Patrick GJ Irwin, Suzanne Aigrain

C2N2 vertical profile in Titan’s stratosphere

Astronomical Journal IOP Publishing 160:4 (2020) 178

Authors:

Melody Sylvestre, Nicholas Teanby, M Dobrijevic, Jason Sharkey, Patrick Irwin

Abstract:

In this paper, we present the first measurements of the vertical distribution of cyanogen (${{\rm{C}}}_{2}{{\rm{N}}}_{2}$) in Titan's lower atmosphere at different latitudes and seasons, using Cassini's Composite Infrared Spectrometer far-infrared data. We also study the vertical distribution of three other minor species detected in our data: methylacetylene (${{\rm{C}}}_{3}{{\rm{H}}}_{4}$), diacetylene (${{\rm{C}}}_{4}{{\rm{H}}}_{2}$), and ${{\rm{H}}}_{2}{\rm{O}}$, in order to compare them to ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$, but also to get an overview of their seasonal and meridional variations in Titan's lower stratosphere from 85 km to 225 km. We measured an average volume mixing ratio of ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ of $6.2\pm 0.8\times {10}^{-11}$ at 125 km at the equator, but poles exhibit a strong enrichment in ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ (up to a factor 100 compared to the equator), greater than what was measured for ${{\rm{C}}}_{3}{{\rm{H}}}_{4}$ or ${{\rm{C}}}_{4}{{\rm{H}}}_{2}$. Measuring ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ profiles provides constraints on the processes controlling its distribution, such as bombardment by Galactic Cosmic Rays which seem to have a smaller influence on ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ than predicted by photochemical models.

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