No Arabic abstract
RATIONALE: The investigation of cryogenic planetary environments as potential harbors for extant life and/or contemporary sites of organic synthesis represents an emerging focal point in planetary exploration. Next generation instruments need to be capable of unambiguously determining elemental and/or molecular stoichiometry via highly accurate mass measurements and the separation of isobaric interferences. METHODS: An OrbitrapTM analyzer adapted for spaceflight (referred to as the CosmOrbitrap), coupled with a commercial pulsed UV laser source (266 nm), is shown to successfully characterize a variety of planetary analog samples via ultrahigh resolution laser desorption/ablation mass spectrometry. The materials analyzed in this study include: jarosite (a hydrous sulfate detected on Mars); magnesium sulfate (a potential component of the subsurface ocean on Europa); uracil (a nucleobase of RNA); and a variety of amino acids. RESULTS: The instrument configuration tested here enables: measurement of major elements and organic molecules with ultrahigh mass resolution (m/{Delta}m higher than 120,000, FWHM); quantification of isotopic abundances with 1.0% (2{sigma}) precision; and, identification of highly accurate masses within 3.2 ppm of absolute values. The analysis of a residue of a dilute solution of amino acids demonstrates the capacity to detect twelve amino acids in positive ion mode at concentrations as low as 1 pmol/mm2 while maintaining mass resolution and accuracy requirements. CONCLUSIONS: The CosmOrbitrap mass analyzer is highly sensitive and delivers mass resolution/accuracy unmatched by any instrument sent into orbit or launched into deep space. This prototype instrument, which maps to a spaceflight implementation, represents a missionenabling technology capable of advancing planetary exploration for decades to come.
In the Solar System, extra-terrestrial organic molecules have been found on cometary primitive objects, on Titan and Enceladus icy moons and on Mars. Identification could be achieved for simple organic species by remote sensing based on spectroscopic methods. However in situ mass spectrometry is a key technology to determine the nature of more complex organic matter. A new concept of mass analyser offering ultra-high mass resolving power of more than 50,000 at m/z 56 (under high vacuum condition about 10-9 mbar) is currently being developed for space applications: the CosmOrbitrap (Briois et al., 2016), based on the OrbitrapTM technology. This work challenges the use of LAb-CosmOrbitrap, a space instrument prototype combining Laser Ablation ionisation and the CosmOrbitrap mass analyser, to identify solid organic molecules of relevance to the future space exploration. For this purpose a blind test was jointly organised by the JAXA-HRMS team (Japan Aerospace Exploration Agency-High Resolution Mass Spectrometry) and the CosmOrbitrap consortium. The JAXA team provided two organic samples, whereas the CosmOrbitrap consortium analysed them without prior information. Thanks to the high analytical performances of the prototype and our HRMS data post-processing, we successfully identified the two molecules as HOBt, hydroxybenzotriazole (C6H5N3O) and BBOT, 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene (C26H26N2O2S), with a mass resolving power of, respectively, 123 540 and 69 219. The success of this blind test on complex organic molecules shows the strong potential of LAb-CosmOrbitrap for future space applications.
The role of polycyclic aromatic hydrocarbons (PAH) and Nitrogen containing PAH (PANH) as intermediates of aerosol production in the atmosphere of Titan has been a subject of controversy for a long time. An analysis of the atmospheric emission band observed by the Visible and Infrared Mapping Spectrometer (VIMS) at 3.28 micrometer suggests the presence of neutral polycyclic aromatic species in the upper atmosphere of Titan. These molecules are seen as the counter part of negative and positive aromatics ions suspected by the Plasma Spectrometer onboard the Cassini spacecraft, but the low resolution of the instrument hinders any molecular speciation. In this work we investigate the specific aromatic content of Titans atmospheric aerosols through laboratory simulations. We report here the selective detection of aromatic compounds in tholins, Titans aerosol analogues, produced with a capacitively coupled plasma in a N2:CH4 95:5 gas mixture. For this purpose, Two-Step Laser Desorption Ionization Time-of-Flight Mass Spectrometry (L2DI-TOF-MS) technique is used to analyze the so produced analogues. This analytical technique is based on the ionization of molecules by Resonance Enhanced Multi-Photon Ionization (REMPI) using a {lambda}=248 nm wavelength laser which is selective for aromatic species. This allows for the selective identification of compounds having at least one aromatic ring. Our experiments show that tholins contain a trace amount of small PAHs with one to three aromatic rings. Nitrogen containing PAHs (PANHs) are also detected as constituents of tholins. Molecules relevant to astrobiology are detected as is the case of the substituted DNA base adenine.
We place the first constraints on the obliquity of a planetary-mass companion (PMC) outside of the Solar System. Our target is the directly imaged system 2MASS J01225093-2439505 (2M0122), which consists of a 120 Myr 0.4 M_sun star hosting a 12-27 M_J companion at 50 AU. We constrain all three of the systems angular momentum vectors: how the companion spin axis, the stellar spin axis, and the orbit normal are inclined relative to our line of sight. To accomplish this, we measure projected rotation rates (vsini) for both the star and the companion using new near-infrared high-resolution spectra with NIRSPEC at Keck Observatory. We combine these with a new stellar photometric rotation period from TESS and a published companion rotation period from HST to obtain spin axis inclinations for both objects. We also fitted multiple epochs of astrometry, including a new observation with NIRC2/Keck, to measure 2M0122bs orbital inclination. The three line-of-sight inclinations place limits on the true de-projected companion obliquity and stellar obliquity. We find that while the stellar obliquity marginally prefers alignment, the companion obliquity tentatively favors misalignment. We evaluate possible origin scenarios. While collisions, secular spin-orbit resonances, and Kozai-Lidov oscillations are unlikely, formation by gravitational instability in a gravito-turbulent disk - the scenario favored for brown dwarf companions to stars - appears promising.
A new setup for doping helium nanodroplets by means of laser ablation at kilohertz repetition rate is presented. The doping process is characterized and two distinct regimes of laser ablation are identified. The setup is shown to be efficient and stable enough to be used for spectroscopy, as demonstrated on beam-depletion spectra of lithium atoms attached to helium nanodroplets. For the first time, helium droplets are doped with high temperature refractory materials such as titanium and tantalum. Doping with the non-volatile DNA basis Guanine is found to be efficient and a number of oligomers are detected.
A search for laser light from Proxima Centauri was performed, including 107 high-resolution, optical spectra obtained between 2004 and 2019. Among them, 57 spectra contain multiple, confined spectral combs, each consisting of 10 closely-spaced frequencies of light. The spectral combs, as entities, are themselves equally spaced with a frequency separation of 5800 GHz, rendering them unambiguously technological in origin. However, the combs do not originate at Proxima Centauri. Otherwise, the 107 spectra of Proxima Centauri show no evidence of technological signals, including 29 observations between March and July 2019 when the candidate technological radio signal, BLC1, was captured by Breakthrough Listen. This search would have revealed lasers pointed toward Earth having a power of 20 to 120 kilowatts and located within the 1.3au field of view centered on Proxima Centauri, assuming a benchmark laser launcher having a 10-meter aperture.