List of Past Planetary Astronomy Lunches (PALS) : 01-Sep-2017 to 31-Dec-2017


Date:   Monday 04-Sep-2017
Speaker:   No PALS (Labor Day)
Title:  No PALS

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 11-Sep-2017
Speaker:   No PALS
Title:  No PALS

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 18-Sep-2017
Speaker:   Anna Engle (UMD)
Title:  Raman Shop: Using Raman Spectroscopy to Probe the Carbon Monoxide/Nitrogen/Methane Ternary System

The New Horizons mission completed its 10-year voyage in 2015 and has given us a new view of the Pluto system. Prior to the mission, the dwarf planet was known to harbor large quantities of nitrogen (N2) in addition to smaller amounts of carbon monoxide (CO) and methane (CH4). With the completion of the fly-by, we were able to see that a sizable portion of these deposits are found in a site formally known as Sputnik Planitia. More fascinating is the discovery that Sputnik Planitia has convective cells that recycle material, presenting a much younger surface than anticipated. With a surface temperature of ~40K on Pluto, it is possible for N2 to undergo the solid-solid α/β phase transition with the presence of CO in the system. With the aid of Raman spectroscopy, we demonstrate that introducing CH4 into the CO/N2 system depresses the temperature at which the α/β phase transition occurs and that the CO/N2/CH4 ternary system on Sputnik Planitia should have <10% CH4 for the phase transition to take place.

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 25-Sep-2017
Speaker:   No PALS
Title:  No PALS

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 02-Oct-2017
Speaker:   Gerbs Bauer (UMD)
Title:  Hot and Dusty: Active Small Body Observations with the Wide-Field Infrared Survey Explorer (WISE)

The NEOWISE survey has detected over 160000 small bodies using the Wide-field Infrared Survey Explorer (WISE) spacecraft, providing unprecedented statistics on the diameters and numbers for various populations. These infrared observations have directly yielded the underlying size distributions of the Near-Earth Asteroids (NEAs), Jupiter Trojans, Main Belt Asteroids and Centaurs, but the active bodies, the comets, often have their nuclei obscured by dust comae. The 164 comets observed during the WISE/NEOWISE prime mission represent the largest infrared survey to date of comets, providing constraints on dust, nucleus size, and CO + CO2 production. The sample includes 56 long-period comets, as well as over 108 short-period comets, from a variety of cometary dynamical sub-classes. We present detailed analyses of the WISE/NEOWISE comet discoveries, and discuss observations of the active comets showing 4.6 micron band excess. We determine size constraints for the majority of the comets in the sample using coma extraction techniques. We also discuss dust tail analysis determining particle size and ejection time constraints.

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 09-Oct-2017
Speaker:   No PALS (PDS Review)
Title:  No PALS

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 16-Oct-2017
Speaker:   No PALS (DPS)
Title:  No PALS

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 23-Oct-2017
Speaker:   TBA
Title:  TBA

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 30-Oct-2017
Speaker:   Adam McKay (GSFC)
Title:  Cometary Composition Studied Via Optical and IR Spectroscopy

Due to their primitive nature, comets are valuable for studying the formation of volatiles in the protosolar disk and their subsequent incorporation into planetary bodies. Over the past 20 years both optical and IR spectroscopy of cometary comae at high spectral resolution have become commonplace, expanding our understanding of cometary volatile composition, cometary activity, and coma photochemistry. In this talk I will highlight recent results aimed at studying cometary activity and composition through optical and IR spectroscopy. I will also discuss studies of the photochemistry occurring in cometary comae and the importance of both optical and IR observations for understanding coma photochemistry. In particular I will discuss recent results from the new iSHELL instrument on NASA IRTF and the NIRSPEC instrument on Keck II pertaining to comets 45P/Honda-Mrkos-Pajdusakova and 41P/Tuttle-Giacobini-Kresak. Both of these comets are members of the Jupiter Family dynamical class of comets, a dynamical class that is underrepresented in compositional studies of comets, especially at IR wavelengths.

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 06-Nov-2017
Speaker:   Doug Hamilton (UMD) - Postponed
Title:  Postponed

Abstract - Postponed

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 13-Nov-2017
Speaker:   PALS is on Thursday this week
Title:  PALS is on Thursday this week

Abstract TBA

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Thursday 16-Nov-2017
Speaker:   CANCELED
Title:  CANCELED

CANCELED

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 20-Nov-2017
Speaker:   Aparna Bhattacharya (UMD/GSFC)
Title:  Measuring Mass of Wide Orbit Low Mass Exoplanets

Microlensing is unique in its sensitivity to cold low mass wide orbit planets. But one of the biggest challenges of current ground based microlensing is that the ground based light curve data fails most of the times to provide us with the physical masses of the planet and the host star. We can measure the mass of these planets and their host stars through several different methods: microlensing parallax and the lens detection from the high resolution images are the two most important methods among them. I will give a brief introduction of each technique and then focus on developing the method of characterization of these planets and their host stars using follow up observations with HST and Keck. I will also demonstrate the technique and how to overcome its challenges due to contamination from the companions and nearby unrelated stars with multiple examples. We have used HST and Keck optical and infrared high resolution images to develop the microlensing exoplanet mass measurement method which will be a primary method of exoplanet mass measurement in WFIRST era. This will help to characterize the cold low mass wide orbit exoplanets and complete the exoplanet census - a mission started by Kepler.

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 27-Nov-2017
Speaker:   Giada Arney (GSFC)
Title:  Strategies for Identifying Habitable Exoplanets

In the future, powerful observatories may be able to search for signs of habitability and life in the atmospheres of exoplanets. But exoplanet atmospheres may not always be straightforward to characterize, and signs of habitability and life may not always be obvious to interpret. This talk will review strategies for detecting signs of habitability and life in the atmospheres of exoplanets with potential future observatories. To broaden our understanding of the spectral appearance of habitable and inhabited planetary states distinct from modern Earth, we can study earlier phases of Earth history, which can be considered “alien” worlds we have access to geochemical data for. Modeling potential biosignatures of earlier phases of Earth history can provide insight into how biospheres dominated by different metabolisms – and environments dominated by different conditions – may be detected. I will discuss the spectral appearance of these “alien” phases of Earth history in the context of possible future observatories.

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


Date:   Monday 04-Dec-2017
Speaker:   Silvia Protopapa (UMD)
Title:  A window to the formation and evolution of the Solar System through compositional analysis

Over the past decade, the synergy of ground- and space-based observations, modeling efforts, and laboratory studies has highlighted vital information on the composition of solar system bodies. I will discuss some of the latest results from New Horizons at Pluto and contrast them with emerging trends seen in other trans-Neptunian objects and comets – the primitive remnants of the planetesimal disk from which the outer planets formed. I will demonstrate how characterizing the composition of these objects, which requires performing laboratory measurements and applying advanced modeling techniques to interpret state-of-the-art ground- and space-based observational data, can shed light on the fundamental processes at play during the epoch of planet formation and throughout the evolution of the solar system. I will also outline future work and perspectives in light of recent results.

For further information contact PALS coordinator Dr. Matthew Knight at knight@astro.umd.edu or (301)-405-2629.


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