Planetary Sciences Division Labs
Modelling, Instrumentation and Data Analysis for Planetary Lighting and Atmosphere
We have wide range of research activities in terms of modelling, instrumentation and data analysis related to the planetary lightning and planetary atmosphere science. A lighting instrument and instrument for radio occultation experiment are under development to study the lightning and atmospheric profile, respectively. We work on vertical profile of planetary atmosphere, effect of dust on the atmosphere, and atmospheric chemical model. The cloud model, lightning generation, wave propagation in planetary atmosphere and ionosphere as well as Schumann Resonance on various planets like Mars and Venus are studied. Possibility exists to carry out research at various levels in the related areas.
- A theoretical model is developed for calculating the Schumann Resonance profiles for modes l = 1, 2 and 3 in the Martian non-homogeneous surface-ionosphere cavity during major dust storm in Martian Year 25. It is found that the lightning can occur within the accumulated dust layer at ~ 20-30 km altitudes. (Haider et al., Advances in Space Research, 2018, accepted)
The identification of crystalline phases of various materials and the quantitative phase analysis subsequent to the identification
The analytical technique is non destructive and diffraction pattern typically follows the Bragg’s equation.
Recent findings on characterisation of spinel group of minerals (as a part of planetary analogue program)is currently under review. Characterisation of carbonaceous chondrite is under progress.
Modelling, Instrumentation and Data Analysis for Interplanetary Dust Science
We have wide range of research activities in terms of modelling, instrumentation and data analysis related to the interplanetary dust science. We work on near surface dust environment, dusty plasma, dust devils and atmospheric dust. An impact ionization dust detector is under development to study the hypervelocity dust particles. The micrometeorites coming to various planetary objects like Mars, Venus and Moons of planets as well as their effects on planetary environment are studied. Possibility exists to carry out research at various levels in the related areas.
- A practical power law size distribution has been suggested for the incoming dust at mars, using MAVEN observations. It has been found that interplanetary dust flux is two orders higher than dust flux from Phobos/Deimos and therefore, the incoming dust at mars could be interplanetary in nature. (Pabari and Bhalodi, Icarus, 288, 1-9, 2017)
- Typically, the dust density based on our practical model for incoming micrometeorites at Mars is 10−7 #/m3. (Pabari et al., Planetary and Space Science, 161, 68-75, 2018)
Determination of isotopic ratio and abundance of stable isotopes of Noble gases (He, Ne, Ar, Kr, Xe) and nitrogen in solid samples, mainly meteorites and returned samples from space missions.
(i) Noble gas mass spectrometer: This is multi-collector mass spectrometer (Noblesse, Nu Instrument U.K.), equipped with three electron multipliers and one faraday cup for simultaneous measurements for three isotopes at a time. It is tuned for noble gases (total 23 isotopes) and nitrogen (2 isotopes) and for measurements from single aliquot.
(ii) Laser: Nd:YAG laser, 15W CW power output for melting single grains, separated from meteorites.
(iii) Resistance Furnace: for extracting gas by melting the sample and gas cleanup cum separation system: to clean and separate the gases.
(i) Indian meteorites: Meteorites which fell in India during last three decades were studied for reconnaissance. Their cosmic ray exposure (CRE) age, trapped noble gases were studied. All the meteorites studied have distinct CRE age and hence they were ejected from different parent bodies. Most of them do not have solar gases and are thus not the part of regolith. Our study of HED meteorites, shows that, different nitrogen and noble gas isotopic ratios present in this samples, indicating that formation of their parent body (asteroid Vesta) was dissimilar as compared with other rocky objects in inner solar system and evolved heterogeneously subsequently. Individual grain study indicates that there were multiple types of rocks (meteorites) impacted and deposited the volatiles on HED parent body.
(ii) Complex exposure of lunar meteorite Y983885: This is new study on lunar meteorite which shows that the constituents of this meteorite (fragments) was exposed on lunar surface for different duration. The noble gas abundance in this meteorite is comparable to those of returned lunar samples and thus provides an opportunity to study solar wind composition and other trapped gases from random sample of lunar surface.
(ii) Recently fallen meteorites: Meteorites fallen elsewhere in world were studied for their cosmic ray exposure age history, understanding trapped gas composition. Most of the meteorite studied have lower gas retention ages (derived from He and Ar) and thus indicate gas loss in recent events like impacts or due to solar heating during their interplanetary sojourn.
Understanding stellar nucleosynthesis and evolution of the Solar system
Nano Secondary Ion Mass Spectrometer (nanoSIMS) is a unique ion microprobe working at high lateral/Spatial resolution. It is based on a coaxial optical design of the ion beam and the secondary ion extraction along with magnetic sector mass analyser and multi-collection system. Its main advantages are as follows:
(I) High spatial resolution: (~50 nm for Cs+ and ~200 nm for O-) Capable of analyzing sub micrometre-size sample.
(II) High mass resolution: Interferences can be resolved with MRP (m/Δm) = 10,000 to 15,000.
(III) High Transmission: ~ 30 x
(IV) Multi-isotope detection; five at a time.
(V) Less destructive technique: Few Å.
(a) High mass Supernovae as a source of Fe-60
60Fe (half-life=2.62My) is a unique product of stellar Nucleosynthesis and its presence in the early solar system and its initial abundance (relative to stable 56Fe) also allow identification of the stellar source of this radionuclide. Initial solar system [60Fe/56Fe]SSI calculated from the data obtained from the two chondrules is (7.2 ± 2.5) x 10-7 (wt. average). The correlation between 26Al and 60Fe records in chondrules observed suggest that these nuclides are co-genetic and a high mass supernova appears to be the most plausible source that delivered short-lived nuclides into the protosolar cloud.
(b) Water on Moon: An inference from study of volatiles from lunar apatite
Phosphate-rich minerals (apatite) from the lunar sample have been measured for the presence of volatiles (Water). The present study indicates that the apatite grains have H2O content, varying from ~2000 to 6000ppm. If we assume that the apatite fractioned from the residual melt at 99% level the parent melt of 15555 had 80-240 ppm H2O that may be considered as the minimum value of water content. This value is close to that inferred for melt inclusion and supports the possibility that 15555 have undergone close system crystallization.
(c) Oxygen Isotopic composition of presolar grain
Oxygen isotopic composition within the meteorite section allows identifying of presolar grains (PSG) and inferring the abundance of the same. Respective isotope anomalies further help in elucidating the stellar origin of the individual grains. 90% grains belong to group1 indicating presolar in a system largely from Asymptotic Giant Branch (AGB) stars indicating a huge contribution of material from AGB star to the molecular cloud from which the Solar System formed.
(d) Corundum within silicate/graphite inclusions in Iron meteorite
The Al-Mg systematics in corundum from the silicate/graphite inclusions of Bhukka meteorite has been initiated to understand the relative formation time and check if it can delineate the process that forms group IAB category of meteorites. Nano Secondary Ion mass spectrometer (NanoSIMS) measurements on four of these corundum grains provide with an initial value of (26Al/27Al)i ~ 5 x 10-5 indicating an early condensates mixing into the iron melt.
Elemental quantification of Earth and Planetary materials
Measures the fluorescent X-rays emitted from a sample when excited by a primary x-ray source.
More than 20 SCI journal publications in reputed journal till date. Meteorites sample analyses even though challenging successfully performed.
In situ elemental quantification of Earth and Planetary materials
Work with WDS technique and it works by bombarding of small sample analytical area by focused electron beam and collection of x-ray photons.
More than 30 SCI journal publications till date and especially useful for characterization of new meteorite fall (e.g. Katol, Kamargaon, Mukundpura) and microstructures of iron meteorites (Kavarpura, Raghunathpura, Bhuka, etc)
Low level in-situ trace element determinations in most solid materials with minimal sample destruction and spatial resolutions of 5 to 150 microns. This is especially very important for planetary sample research, where sample size is tiny and amount is very small
Basic Working Principle of LA-ICPMS
Laser unit: Frequency quintupled, Q-switched Nd:YAG laser, 213 nm; Spot size range: 4–200 μm; > 3 mJ/pulse laser energy; Built-in multi-spot analysis, line scans and raster, segmented line scanning, area scan and raster and advanced depth; Carrier gas typically helium
Mass-spectrometer unit: Quadrupole ICP-MS Spectrometer; Qtegra Control software platform
The system is in establishment stage; near-future aim is to obtain data from Martian meteorite samples.