IGRINS Science Workshop High Spectral Resolution Mid- Infrared Spectroscopy as a Probe of the Physical State of Planetary Atmospheres August 26, 2010

IGRINS Science Workshop Advantages of High Spectral Resolution Increased sensitivity to unresolved spectral features (changes linearly with resolving power) Increases spectral separation of observed emission or absorption features allowing for unique identifications of a multitude of molecular features when molecular rotation-vibration bands overlap. Increases the amount of open spectral space to observation by reducing blending and increasing separation of telluric absorption features. The line shape of resolved spectral features can be use to retrieve information on velocity of the gas (compact H 2 regions, galaxies, etc), information on vertical variation of temperature or abundance of molecules in a planetary atmosphere, or the ability to separate distinct clouds of gas along a given line of sight.

IGRINS Science Workshop TEXES: Texas Echelon Cross Echelle Spectrograph Operates between 5 and 25  m A ground based prototype for EXES, an instrument to be flown on SOFIA

IGRINS Science Workshop inches long 0.3 inch groove spacing 0.03 inch groove height 0.3” Echelon Grating

IGRINS Science Workshop T.K. Greathouse J.I. Moses J.H. Lacy M.J. Richter NASA/JPL/Space Science Institute Probing Stratospheric Chemistry, Energetics, and Dynamics. A Detailed Study of Giant Planet Stratospheres

IGRINS Science Workshop Pressure (bar) Temperature (Kelvin) Troposphere Stratosphere Thermosphere Tropopause Mesosphere Mesopause Stratopause General Atmospheric Structure

IGRINS Science Workshop Process Dependencies Stratospheric Temperatures  Chemistry  Latitude?  Season?  Insolation  Latitude  Season  Solar Flux  Molecular Abundances  Latitude?  Season?  Dynamic Mixing?  Heating  Aerosols  Chemistry  Insolation  Advection?  Cooling  Molecular Abundances  Chemistry  Advection?

IGRINS Science Workshop Moses et al. 2000, Icarus. Question: What molecules exist in the stratosphere?

IGRINS Science Workshop Using Doppler Shifts for Unambiguous Detection of C 3 H 8 First Detection of Propane on Saturn -20  10  Latitude -80  10  Latitude

IGRINS Science Workshop ISO Schulz et al First Detections of C 2 H 4 in Neptune

IGRINS Science Workshop A Second Detection AKARI data Fletcher et al. 2010

IGRINS Science Workshop The First Spectrally Resolved Detection of C 2 H 4 on Neptune

IGRINS Science Workshop Spectral Line Separation The Unambiguous Detection of C 3 H 8 Propane on Titan Roe et al Propane Measure weak lines Measure features in crowded spectral regions

IGRINS Science Workshop Seasonal Studies

IGRINS Science Workshop Temperature Retrievals Using thermal emission spectra to retrieve temperatures requires knowledge of mixing ratio of observed molecule. Methane serves this purpose. Homogeneously mixed vertically and horizontally we can use this useful molecule as a thermometer.

Courtesy Glenn Orton southern winter southern spring southern summer

IGRINS Science Workshop CH 4 emission from –80° latitude

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IGRINS Science Workshop Ethane Spectrum with Missing Features

IGRINS Science Workshop A Few Project Ideas for IGRINS Auroral studies on Jupiter –IGRINS gives access the simultaneous acquisition of H 2 and H 3 + emission features. Cloud elevation studies on Saturn and Jupiter. Occultation observations –Very good probe of CH 4 vertical density distribution. Comet Observations Kuiper belt objects probably best left to GMTNIRS

IGRINS Science Workshop