List of Past Planetary Astronomy Lunches (PALS) : 01-Jan-2017 to 01-Jun-2017


Date:   Monday 30-Jan-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 06-Feb-2017
Speaker:   Cristina Thomas (PSI/GSFC)
Title:  Understanding Our Solar System Through Asteroid Spectroscopy

Asteroids are essential to our understanding of the history of our Solar System. Unlike the major planets, which have undergone major alterations from a variety of physical, geological, and atmospheric processes, most asteroids are minimally altered objects that enable us to investigate the cosmochemical variations in the early Solar System.

Each asteroid population contributes to our understanding of the Solar System as a whole. My research utilizes reflectance spectroscopy of asteroids throughout the Solar System to remotely infer their compositions and surface properties. I will highlight my recent projects and discuss how these objects can be used to understand the formation and evolution of our Solar System. I will discuss spectra from selected asteroid families, a targeted search for the H chondrite source region, and future asteroid observations with JWST.

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


Date:   Monday 13-Feb-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 20-Feb-2017
Speaker:   Katherine Bermingham (UMD)
Title:  Investigating Planetary Accretion Through Isotope Genetic Tracing

Meteorites can provide us with significant insights into the chemical evolution of the Solar System. My research uses the isotopic characteristics (or genetics) of meteorite groups to investigate how the composition of the solar nebula varied and identify potential candidates for Earth's building blocks. I will provide an overview of this approach and insights into late accretion additions to Earth, an important phase of terrestrial accretion which may have seen the delivery of vital quantities of water and organics.

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


Date:   Monday 27-Feb-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 6-Mar-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 13-Mar-2017
Speaker:   Colin Snodgrass (The Open University)
Title:  Exploring water in the asteroid belt: Proposed ESA missions Castalia and CASTAway

Recent observations and models suggest that there could be a significant amount of water ice in the asteroid belt. The amount of water there is an important constraint on solar system formation and evolution models, but is difficult to assess with current technology. I will discuss attempts to detect this water from Earth, and introduce two missions which were proposed to the latest ESA M-class call, to visit the asteroid belt and directly investigate water there. Castalia is a mini-Rosetta mission to rendezvous with a main belt comet, while CASTAway is a combined survey and tour that would explore the diversity of bodies in the main belt.

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


Date:   Monday 20-Mar-2017
Speaker:   No PALS (Spring Break)
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 27-Mar-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 3-Apr-2017
Speaker:   Rok Nezic (Armaugh Observatory) & Nora Eisner (UMD/University of Sheffield)
Title:  Student talks

Speaker: Rok Nezic (Armaugh Observatory) Title: Post-perihelion observations of comet 67P/Churyumov–Gerasimenko with VLT Abstract: In parallel with the NASA/ESA Rosetta mission at the comet, an extensive ground-based observing campaign of comet 67P/Churyumov–Gerasimenko was coordinated by Colin Snodgrass before, during, and after the space mission's main phase. As part of this wider campaign, the comet was observed with VLT's 8.2 metre telescope in polarimetric mode, using the FORS instrument, in January and February 2016, past comet's perihelion of August 2015. In this talk I will present the observational methods used and the preliminary analysis of those results in the broader context of cometary observations. I will also briefly discuss the future work required for improving our understanding of this comet.

Speaker: Nora Eisner (University of Maryland/University of Sheffield) Title: Observations of comet 41P/Tuttle-Giacobini-Kresak during its 2017 close approach Abstract: Comet 41P/Tuttle-Giacobini-Kresak is in the midst of an exceptionally close approach to Earth (0.14 AU on 2017 April 1). I will discuss our recent observations of 41P using Lowell Observatory's 42in telescope and supplemented by data from Lowell Observatory's 0.8m robotic telescope and the Discovery Channel Telescope. Notably, we discovered that the apparent period, as determined from CN coma morphology, was changing steadily during our observations and was significantly different than that determined by Farnham et al. just 2 weeks earlier.

Abstract TBA

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


Date:   Monday 10-Apr-2017
Speaker:   No PALS (ACM)
Title:  TBA

Abstract TBA

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


Date:   Monday 17-Apr-2017
Speaker:   No PALS
Title:  No PALS

Abstract No PALS

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


Date:   Monday 24-Apr-2017
Speaker:   Michael Kelley (UMD)
Title:  Cometary Orbital Trends with Spitzer

Cometary activity, i.e., the mass-loss process, is driven by the sublimation of volatiles. The three most abundant volatiles are water, carbon dioxide, and carbon monoxide, and each plays a different role in cometary activity. By observing the distribution and abundances of these gases in the coma, we can obtain a better understanding of their contributions to activity and the evolution of comets. The water, CO2, and CO coma distributions have been studied in spacecraft missions to comets 9P/Tempel 1, 103P/Hartley 2, and 67P/Churyumov-Gerasimenko. These data exhibit a variety of coma asymmetries, apparently caused by surface heterogeneities and/or thermal history. In order to connect the detailed observations from comet missions to the whole comet population, a better understanding of the role of water and CO2 in cometary activity is needed. To that end, we initiated a long-term survey of comets we call Cometary Orbital Trends. In this survey, we aim to measure water, CO2, and dust in a set of ~20 comets over year timescales. In this talk, I will present our survey and first results, including the aphelion activity of comet 2P/Encke, and the dust-to-CO2 ratio of the comet population.

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


Date:   Monday 1-May-2017
Speaker:   Mike DiSanti (GSFC)
Title:  High-resolution spectroscopy of Comet 45P/Honda-Mrkos-Pajdusakova with iSHELL at the IRTF: Secure detections of the under-studied hyper-volatiles CO and CH4 in a Jupiter-family comet

We observed Jupiter-family comet (JFC) 45P/Honda-Mrkos-Pajdusakova (hereafter 45P) shortly following its perihelion passage, using the new NASA-Infrared Telescope Facility 1-5 micron crossed-dispersed spectrograph (iSHELL) at high spectral resolving power (~4.5*10^4), and obtained the first molecular detections in a comet with this powerful instrument. We report water production, and production rates and abundance ratios relative to H2O on two dates (UT 7 and 8 January 2017) for eight trace parent molecules (i.e., native ices): CO, CH4, H2CO, CH3OH, HCN, NH3, C2H2, and C2H6. In all cases trace species were observed simultaneously with H2O and/or its proxy OH prompt emission. This allowed molecular abundance ratios to be established independent of systematic uncertainties such as potential temporal variations in gas production and differential slit losses among settings. Our observations revealed depleted abundances of CO and HCN, and enriched CH3OH relative to most comets measured to date. Most significantly, the highly favorable geocentric Doppler shift of 45P (approximately -35 km s‑1) permitted sensitive measures of CO and CH4. These hyper-volatiles are substantially under-characterized in JFCs, and therefore statistics on their abundances are severely lacking. Our measurements of 45P therefore provide a foundation from which to build a database of statistically meaningful abundances of CO and CH4 in JFCs. I will summarize our results for comet 45P, place these in the context of the continually growing taxonomy of parent volatile abundances among comets, and provide a summary of recent and planned future comet observations with iSHELL.

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


Date:   Monday 8-May-2017
Speaker:   Jamie Elsila (GSFC)
Title:  Amino Acids in the Solar System

The organic contents of meteorites and comets reflect early solar system chemistry, as well as the physical and chemical processes that have occurred in the past 4.5 billion years. Among the most well-studied of the organic compounds present in these extraterrestrial materials are amino acids. Amino acids have been detected in a variety of meteorites, as well as in materials collected from NASA's Stardust mission to Comet Wild-2; recently, observations by the ROSETTA mission also identified glycine in the coma of 67P/Churyumov-Gerasimenko.

Amino acids are of particular interest to astrobiology and astrochemistry research for several reasons: (1) they are essential to life on Earth; (2) they are a structurally diverse group of compounds; and (3) some of them possess large enantiomeric excesses of extraterrestrial origin. We have examined the abundances, structural distributions, stable isotopic ratios, and enantiomeric compositions of amino acids in meteorites from all eight carbonaceous chondrite groups, as well as representatives of other meteorite classes and materials from comet Wild-2. These studies show a wide diversity in the amino acids present across these samples. This diversity highlights the potential roles of parent body processes and composition on the organic content of these bodies, as well as the potential for a variety of formation mechanisms and organic reservoirs in the solar system. In addition, the observed large l-enantiomeric excesses of some proteinogenic amino acids in certain meteorites (up to ~60%) may be relevant to understanding the origin of homochirality in life on Earth, although the potential mechanisms leading to these enantiomeric excesses are currently poorly understood.

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


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