DPS/CEPSAR Seminar Series
When: Monday 3 December 2012 at 1.30pm
Where: Berrill Lecture Theatre
Speaker: Mark Brandon (The Open University)
CEPSAR 2012 Christmas Lecture II
Frozen Planet: Working on a very large OU/BBC primetime co-pro
The OU was a co-production partner in the BBC ‘Frozen Planet’ series and members of the University were working on the series since early 2008. Mark will talk about his experiences of the co-production process, going on a shoot in the Arctic with Sir David Attenborough and a BBC film crew, the production of a short course S175 Frozen Planet, and how science was the driving force throughout.
DPS/CEPSAR Seminar Series
When: Friday 23 November 2012 at 11.00am
Where: Robert Hooke Building Seminar Room
Speaker: Irakli Simonia (Ilia State University, Tblisi, Georgia)
Title: Frozen organic in comets and the circumstellar environment
Abstract:
Unidentified emissions are observed in spectra of most comets. These separate lines and bands were not possible to be identified earlier by standard methods. A great number of narrow lines of unknown nature were tabulated. For solving the problem of unidentified cometary emissions, had developed the theoretical model of frozen hydrocarbon particles of icy haloes of comets and described the mechanism of FHPs photoluminescence [1,2].This model suggests PAHs in alkanes frozen mixture as fine dispersed icy particles. The comparition of laboratory and observed data showed that hundreds of cometary emissions not identified earlier are the photoluminescence of frozen hydrocarbon particles. In [2] suggested that the mixture of frozen polycyclic aromatic hydrocarbons and alkanes could be among the ices of cometary nuclei. These mixtures are the solid solutions of substance – solvent type. Here the substance means polycyclic aromatic hydrocarbons (PAHs), and the solvent –acyclic hydrocarbons. The optical properties of the solution are determined by the properties of a solvent, by the conditions of crystallization of the solution, by the existence of luminescent component, by the character of interaction between the components of the solution and by the content of additional impurities in the solution (including carbonaceous). The surface layers of icy cometary nucleus are the sources of frozen hydrocarbon particles of different sizes ejected and carried to the circumnuclear area as the comet approaches the Sun. The sizes of individual FHP can vary from micron to millimeter. FHP can has the characteristic color inherent in frozen mixture of PAH and acyclic hydrocarbons. The solar ultraviolet radiation excites the photoluminescence of icy particles of halo. Low albedo of particles that consist of the mentioned mixtures, and the high quantum yield of Photoluminescence of PAHs make it possible to register the corresponding luminescent emissions. The quantum yield of photoluminescence of FHPs can really be rather high. In favor of this assumption speaks the results of laboratory investigations. In [3] showed that for PAH molecules the quantum yield equals to 90-100%. UV photons of solar origin cause the photoluminescence of cometary FHPs in the range of 3800-7000 A. Results of our new investigations of PAHs in comets will presented. Role of absorption features for determination of organic composition of cometary icies and other small bodies will considered. New complex model mineral core – frozen organic mantle will suggest within problem of origin of extended red emission of reflection, proto-planetary, and planetary nebula.
References
1. Simonia, I. (2007) Astrophys. Space Sci., 312, 27.
2. Simonia, I. (2011) AJ, 141,56.
3. Gudipati, M.S., et al. (2003) AJ, 583, 523.
Refreshments will be available from 1.45pm.
DPS/CEPSAR Seminar Series
When: Monday 19 November 2012 at 2.30pm
Where: Life, Health & Chemical Sciences (LHCS) Seminar Room
Speaker: Professor Don Pollacco (Warwick University)
Title: Future transit surveys for exoplanets
Abstract:
Much of what we know about exoplanets is derived from transiting systems. The orbital geometry of these objects allows an accurate determination of orbital inclination and relative planetary size (compared to the host star) and hence when combined with mass measurements from doppler spectroscopy, their bulk densities. Further observations can also reveal details about the dynamical history of the planet and its atmosphere. Here i will briefly discuss the current transit surveys and their successes (and failures) but look forward to the new generation of ground and space based experiments expected to be commissioned over the next decade.
Refreshments will be available from 2pm.
DPS/CEPSAR Seminar Series
When: Thursday 15 November 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Professor Alex Halliday (Oxford University)
Title: The origin of the Moon and the delivery of Earth's volatiles
Abstract:
The mostly widely accepted model for the origin of the Moon is that it formed in a Giant Impact between an Earth that was roughly 90% formed and a Mars-sized impactor sometimes called "Theia", which added most of the remaining 10%. This is based on smooth particle hydrodynamic simulations that need to conserve angular momentum with relatively little overall loss over time. The amount of energy imparted would be significant and some have suggested that Earth could not have acquired and retained its current volatiles until after the Moon formed, adding support to the idea of a subsequent "late veneer". However, there are problems with this Giant Impact model as there are with explaining Earth's volatiles with a late veneer. In particular most of the Moon is derived from Theia in the simulations whereas oxygen isotopes provide evidence that most of the atoms came from Earth. In addition Earth's volatiles as currently known have H/N and H/C ratios that are distinct from those expected from volatile rich chondritic or cometary veneers. The overall patterns of noble gases and major volatiles make more sense as a series of Solar, chondritic and cometary additions punctuated by major differential losses to the core or to space. As such some of the volatiles appear to predate any late veneer and possibly also predate the Giant Impact. The atmospheres of Mars and Venus appear to be broadly similar to this. Some of the new dynamic models that are now being developed for the Giant Impact appear to be more consistent with this. They explain the oxygen isotopic similarity with the Earth and offer a broader array of possibilities for the energy imparted and the amount of mixing and volatile loss that might have been achieved.
Refreshments will be available from 2pm.
DPS/CEPSAR Seminar Series
When: Wednesday 14 November 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Dr Everett Gibson (Senior Scientist Astromaterials Research Office, NASA Johnson Space Center, Houston, USA)
Title: Curiosity on Mars and status of the life on Mars question
Abstract:
In 1996 the stunning hypothesis published in SCIENCE that features within the ALH84001 meteorite were consistent with early microbial life on Mars began a revolution of research on Martian meteorites and re-ignited the exploration of Mars. The life on Mars hypothesis has been debated extensively over the past 16 years. A fleet of modern spacecraft have visited the Red planet. We believe the hypothesis is viable today and the original lines of evidence presented remain robust. It has been further strengthened by the presence of abundant biomorphs and reduced carbon chemistries in additional Martian meteorites. The biomorphs, while not completely definitive for microbial life, are clearly associated with Martian aqueous alteration processes (crack-filling iddingsite formation) and organic matter. These features are nearly identical to terrestrial biomorphs known to have formed by microbial activity. New data obtained by remote platforms and landers on Mars have significantly enhanced the idea that conditions on Mars could support habitability. These missions have shown the presence of an early magnetic field detected by the discovery of strongly magnetized crustal rocks, the presence of abundant surface water and recent near-surface flowing water, the presence of early clay minerals and carbonates with associated reduced organic matter, and the presence of methane plumes in the atmosphere that may have a biological origin. Combining all of the new data from the Mars missions with data from Martian meteorites, the case for life on Mars appears to be much stronger, and is strengthening each year. The Curiosity Rover currently on Mars offers new opportunities to study the nature of biogenic elements in-situ and the mineralogy in the Gale crater site. Results from the Curiosity Rover and recent studies of Martian meteorites will be discussed.
Dr. Everett K. Gibson is a Visiting Professor at the Open University. He is a Senior Scientist in the Astromaterials Research Office, NASA Johnson Space Center, Houston, TX. Dr. Gibson has been associated with the Open University since 1984 when he was the first Leverhulme Fellow at the OU. He was one of six Interdiscipline Scientists for the Mars Express/Beagle 2 Mission.
Refreshments will be available from 2pm.
CEPSAR Seminar Series
When: Thursday 8 November 2012 at TBC
Where: Robert Hooke Building Seminar Room
Speaker: Dr Jamie Gilmour (Manchester University)
Title: The Next Next Generation of Noble Gas Analysis
Abstract: The ultrasensitive resonance ionization mass spectrometer, RELAX, has been used for the isotopic analysis of xenon from solar system samples since the early 1990s. We have now developed a new instrument for krypton isotopic analysis at the same high sensitivity, and plan to develop the capability for simultaneous analysis of xenon and krypton. I will discuss these developments and report some recent results from these instruments.
Refreshments will be available from 2pm.
CEPSAR Seminar Series
When: Thursday 1 November 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Dr Maria Schönbächler (Zurich)
Title: The making of asteroids and the Earth - Clues from the Pd-Ag chronometer
Abstract:
The short-lived Pd-Ag decay system represents a chronometer that can be used to determine the timing and physical conditions of planet formation. In this talk, I will show that the Pd-Ag decay system provides powerful constraints on (i) the crystallization history of iron meteorites, which are thought to represent samples from small asteroidal cores; (ii) the timing of moderately volatile element depletion in the early solar system that most rocky planetary bodies experienced and (iii) the formation of the Earth. For example, the Earth’s mantle is similar in Ag isotope composition to primitive, volatile-rich CI chondrites. Therefore, the Earth must have accreted a significant amount of material abundant in moderately volatile elements. Contradictory evidence from chromium and strontium isotopes can be reconciled with the Pd-Ag system by heterogeneous accretion. In such a scenario, the early accretion of volatile-depleted material is followed by volatile-rich material with possibly high water content while core formation is still ongoing. The model also indicates that the Moon-forming giant impact likely involved the collision with a Mars-like protoplanet enriched in moderately volatile elements.
Refreshments will be available from 2pm.
DPS/CEPSAR Seminar Series
When: Friday 26 October 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Professor Steve Eales (Cardiff University)
Title: Dust, Star Formation and Dark Matter from z=0 to z=5 - the Herschel View
Abstract:
I will start by describing two Herschel surveys of the nearby Universe.
I will show evidence that galaxies have extended dust halos and evidence, from our observations of the Andromeda Galaxy, for variations in the properties of the dust within a galaxy.
Refreshments will be available from 2pm.
DPS/CEPSAR Seminar Series
When: Thursday 18 October 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Dr David Pinfield (RCUK Academic Fellow, Hertfordshire University)
Title: Searching for the coolest atmospheres using large scale surveys
Abstract:
I will present a summary of my research activities on brown dwarfs and exoplanets, and then focus in on a new programme - a search for the coolest Y dwarfs in the Wide-field Infrared Survey Explorer (WISE). WISE is a space-based satellite that has made an all-sky survey in the mid-IR. The WISE team has used this survey to identify a new spectral class, the Y dwarfs, and revealed 13 objects with Teff=300-500K (i.e. as cool as room temperature). I will present a new technique for searching in WISE for late T and Y dwarfs that probes more effectively than previous searches at fainter magnitudes, and is revealing an unidentified population of faint high proper motion objects. I will present the early results of this programme and consider what this search might reveal as objects are followed up in the next few years.
Refreshments will be available from 2pm.
CEPSAR Seminar Series
When: Thursday 11 October 2012 at 2.30pm
Where: Robert Hooke Seminar Room
Speaker: Professor Martin Lee (School of Geographical and Earth Sciences, University of Glasgow)
Title: Mechanisms and chronologies of aqueous alteration of the crust of Mars: Evidence from the nakhlite meteorites
Abstract:
The nakhlite meteorites are olivine-bearing clinopyroxenites that were impact ejected from the crust of Mars. As they contain a suite of secondary minerals that crystallized from aqueous solutions, these meteorites offer a unique opportunity to investigate the longevity of water in the crust and the mechanisms by which it interacted with primary (magmatic) minerals.
This presentation will describe new insights into the processes and products of aqueous alteration from analysis of the Nakhla and Lafayette meteorites using scanning and transmission electron microscopy and electron backscatter diffraction. Results to date have revealed the importance of dissolution of olivine prior to secondary mineralization. The preferred crystallographic orientation of sheet pores within the olivine grains reveals that mechanisms and rates of water-rock interaction were strongly controlled by the presence of [001] screw dislocations and (001) subgrain boundaries. The gap in time between silicate mineral dissolution and secondary mineralization is currently unknown, but could have been anywhere between days and >300 Ma. The secondary minerals that occluded the sheet pores within Lafayette crystallized in the order of siderite-phyllosilicate-Fe oxide-nanocrystalline smectite-phyllosilicate, whereas in Nakhla the first phyllosilicate generation is absent and the latter one is intergrown with microcrystalline gypsum, which may or may not be Martian in origin. Complementary D/H work is currently underway in order to ascertain the degree of interaction of the secondary minerals with the terrestrial atmosphere, and 39Ar-40Ar analyses are being used to determine the crystallization ages of primary and secondary minerals.
DPS/CEPSAR Seminar Series
When: Thursday 4 October 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Dr Katherine Joy (Manchester)
Title: Lunar meteorites: Advancements in lunar science from studies of lunar meteorites
Abstract:
Manned and unmanned missions to the Moon returned ~382 kg of lunar rocks and soils from equatorial regions on the lunar nearside. Therefore, interpretations of the Moon’s geological past have been derived from a geographically restricted dataset. Lunar meteorites are sourced from random localities on the surface, and, thus, provide global geological sampling of the Moon. This talk will discuss how lunar meteorites have contributed to a better understanding of the geological and impact history of the Moon and inner Solar System.
Refreshments will be available from 2pm.
CEPSAR Seminar Series
When: Thursday 27 September 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Professor Mark Burchell (University of Kent)
Title: Hypervelocity Impacts - Destructive or Not?
Abstract:
We are all probably aware of the catastrophic nature of giant impacts from space – they killed the dinosaurs! But there is also great interest in the fate of the impactor itself. Does anything survive an impact at speeds above 1 km s-1 or so? Is it altered? Does it have any scientific value? This will be discussed using results of experiments and referring to real solar system examples (some as yet unproven). The talk will cover minerals, organics and of course microbes (which can be surprisingly resilient to shock pressures).
Refreshments will be available from 2pm.
DPS/CEPSAR/Rocsoc Seminar
When: Tuesday 25 September 2012 at 11.15am
Where: Gass Building Seminar Room
Speaker: Professor Stephen Mojzsis (University of Colorado, USA)
Title: Reduced, reused and recycled: Detrital zircons in the ca. 3750-3780 Ma Nuvvuagittuq supracrustal belt (Quebec, Canada)
Abstract:
A key discovery from the oldest terrestrial zircons has been that the dichotomy of granitic and basaltic crust was established within about 200 Myr of Earth's formation. Understanding the eventual fate of this primordial crust would greatly add to what we know about the nature of the Hadean Earth. Potential clues arise from combined 147,146Sm-143,142Nd isotope data reported from the Nuvvuagittuq supracrustal belt (NSB) in northern Québec. Some Ca-poor amphibolites and granitoid gneisses of the NSB preserve anomalously low 142Nd/144Nd compared to Bulk Silicate Earth; these also show weak positive correlations against 147Sm/143Nd which were used by O'Neil et al. (2008) to assign a ca. 4300 Ma age. Alternatively, these compositions are inherited from an ancient enriched crustal source that was assimilated later during the formation of the NSB. We present ion microprobe U-Pb ages for detrital zircons from NSB metasediments (quartzites and quartz-biotite schists) that are statistically indistinguishable from previously reported ca. 3800 Myr-old zircon ages for granitoid gneisses in the same supracrustal succession, including those that preserve low 142Nd/144Nd. The youngest detrital zircon cores of igneous derivation define a maximum age for the NSB some 500 Myr younger than that derived from 142Nd/144Nd vs. 147Sm-143Nd regressions. Like variable 142Nd/144Nd ratios reported elsewhere (West Greenland, Western Australia), we propose that these anomalous values were carried over from later incorporation of an ancient component that survived the bombardment epoch.
DPS/CEPSAR Seminar Series
When: Friday 21 September 2012 at 11.15am
Where: Robert Hooke Building Seminar Room
Speaker: Dr Carl Allen (NASA Johnson Space Centre, Houston)
"Gale Crater - Why are we there and what do we hope to learn?"
Abstract:
The Mars Science Laboratory Rover Curiosity is commencing a two-year investigation of Gale crater and Mt. Sharp, the crater’s prominent central mound. Gale is a 155 km, late Noachian / early Hesperian impact crater located near the dichotomy boundary separating the southern highlands from the northern plains. The central mound is composed of layered sedimentary rock, with upper and lower mound units separated by a prominent erosional unconformity. The lower mound is of particular interest, as it contains secondary minerals indicative of a striking shift from water-rich to water-poor conditions on early Mars. A key unknown in the history of Gale is the relationship between the sedimentary units in the mound and sedimentary sequences in the surrounding region.
We are employing orbital remote sensing data to determine if areas within a 1,000 km radius of Gale match the characteristics of sedimentary units in Mt. Sharp. Our results are consistent with the hypothesis that sedimentary units in both the upper and lower sections of the Gale mound are related to nearby regional units located along the dichotomy boundary. This relationship supports an inferred geologic history that includes several episodes of widespread sedimentary deposition and erosion in the martian mid-latitudes. In this model Mt. Sharp is the remnant of regional sedimentary deposits that partially or completely filled the crater, became lithified, and were subsequently deeply eroded. Key questions that will be addressed by Curiosity include the compositions of the sediments, the modes of deposition, the mechanisms of lithification, and the nature of the erosion.
DPS/CEPSAR Seminar Series
When: Thursday 20 September 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Dr Jean Christophe Pouilly (CIMAP-GANIL, Caen)
Title: Interaction of biologically-relevant molecular systems with atomic ions and electrons in the gas phase
Abstract:
In cancer treatments involving irradiation of malignant cells by photons, protons or heavy ions like Carbon, a number of secondary particles are produced along the track of the primary particle. Among them, electrons and ions with keV kinetic energy can induce significant damage to DNA and other biological molecules. Therefore, it is of particular importance to investigate the physics and chemistry of this damage at the molecular scale.
In Caen, we study the interaction between neutral biologically-relevant molecular systems in the gas phase and keV kinetic energy atomic ions by means of mass spectrometry. These last years, we focused on building blocks of DNA and proteins: nucleobases and amino acids. In particular, we compared the case of the isolated molecule with that of the molecule embedded in a cluster, to obtain the effect of a molecular environment. In this talk, I will highlight our recent experiments on the nucleobase Adenine that we studied isolated, in pure Adenine clusters, in pure hydrated clusters, and in mixed Adenine-Thymine clusters. We obtained several evidences for the protonation of Adenine induced by the interaction with atomic ions. Such behavior has already been observed after the absorption of photons 1-3 as well as after collisions with electrons 2. In the case of beta-amino acid clusters, a striking result is the formation of peptide ions. I will also present our work in collaboration with the group of Steen Brønsted Nielsen in Aarhus, which pioneered the Electron Capture Induced Dissociation (ECID) of peptide cations. Very recently, we investigated the influence of non-covalently binding acetonitrile and 18-Crown-6 ether to aromatic tripeptides on their ECID patterns, and found dramatic differences.
(1)Barc, B.; Cahillane, P.; Mason, N. J.; Eden, S. 2011. (2) Kim, N. J.; Kang, H.; Jeong, G.; Kim, Y. S.; Lee, K. T.; Kim, S. K. Journal of Physical Chemistry A 2000, 104, 6552. (3) Gador, N.; Samoylova, E.; Smith, V. R.; Stolow, A.; Rayner, D. M.; Radloff, W.; Hertel, I. V.; Schultz, T. The Journal of Physical Chemistry A 2007, 111, 11743.
Refreshments will be available from 2pm.
CEPSAR Seminar Series
When: Thursday 13 September 2012 at 2.30pm
Where: Robert Hooke Building Seminar Room
Speaker: Dr Peter Hoppe (Max Planck Institute for Chemistry, Mainz, Germany)
NanoSIMS Studies on Dust from Supernovae
Abstract:
Primitive Solar System materials contain small quantities of so-called presolar grains that formed in the winds of evolved stars and in the ejecta of stellar explosions. Laboratory studies of these pristine samples have provided a wealth of astrophysical information, such as on stellar nucleosynthesis and evolution, dust formation around stars, processing of dust in the interstellar medium, and formation of our Solar System. An important measurement technique is Secondary Ion Mass Spectrometry (SIMS) which permits to do isotope studies at the sub-micrometer scale. In this talk I will focus on isotope measurements on presolar silicon carbide and silicate grains from supernovae (SNe), done with the NanoSIMS ion probe at the Max Planck Institute for Chemistry. I will present results for selected elements and will discuss implications for SN nucleosynthesis, Galactic chemical evolution, and mixing and molecule chemistry in SN ejecta.
Coffee will be available from 2pm.
Figure: A presolar SiC grain from a supernova. Scale bar is 200 nm.
DPS/CEPSAR Seminar Series
When: Monday 3 September 2012 at 2.30pm
Where: Robert Hooke Seminar Room
Speaker: Professor Olivier Mousis
Title: Formation conditions of icy planetesimals in the primitive nebula: implications for the composition of the outer Solar System
Abstract:
Formation scenarios of the solar nebula invoke two main reservoirs of water ice that may have taken part concurrently into the production of solids. In the first reservoir, which is located within the heliocentric distance of 30 AU, water ice infalling from the Interstellar Medium (ISM) initially vaporized into the hot inner part of the disk and condensed in its crystalline form during the cooling of the solar nebula. The second reservoir, located at larger heliocentric distances, is composed of water ice originating from ISM that did not suffer from vaporization when entering into the disk. In this reservoir, water ice remained mainly in its amorphous form. From these considerations, we discuss here the trapping conditions of volatiles in planetesimals produced within the outer solar nebula and their implications for the origin and composition of gas giant planets, their surrounding satellite systems and comets. In particular, we show that the formation of icy planetesimals agglomerated from clathrate hydrates in the solar nebula can explain in a consistent manner the volatiles enrichments measured at Jupiter and Saturn, as well as the composition of Titan's atmosphere.
Coffee will be available from 2pm.
Image: NASA
CEPSAR Seminar Series
When: Thursday 14 June 2012 at 2.30pm
Where: Robert Hooke Seminar Room
Speaker: Professor Subir Sarkar (Head of Particle Theory Group, Oxford)
Title: "Discovering Dark Matter"?
Abstract:
The search for dark matter is intensifying with major direct detection experiments such as CDMS and XENON setting ever lower bounds on the scattering cross-section which are beginning to cut into the parameter space for relic neutralinos in supersymmetric models. However several other experiments such as CoGeNT, CRESST and DAMA have reported results consistent with much lighter dark matter particles. I will discuss whether the conflicting claims can be reconciled, and what this may be telling us about both about the nature of dark matter and its astrophysical distribution in the Galaxy.
Coffee will be available from 2pm.