scholarly journals Properties of Ices and Grains: An experimental study

1983 ◽  
Vol 6 ◽  
pp. 347-354
Author(s):  
Bertram Dorm
Keyword(s):  
Low Temperatures ◽  
Proton Irradiation ◽  
Cosmic Ray ◽  
Oort Cloud ◽  
The Sun ◽  
Organic Residue ◽  
History Of ◽  
Composition Structure ◽  
Galactic Cosmic Ray ◽  
Complex Organic

AbstractProton irradiation of a variety of ice mixtures were carried out to study the effect of galactic cosmic ray irradiation of comets in the Oort Cloud. Three significant effects were noted (1) production of new molecules; (2) production of a more energetic ice at low temperatures; (3) production of a non-volatile, complex organic residue. These phenomena suggest various effects on new comets approaching the sun including enhanced activity. Experiments on the condensation of silicate grains provide information on the condensation mechanism and properties of grains. Controlled annealing of the amorphous condensates shows how crystallization occurs. Infrared spectra of different stages of crystallization contain features that may identify composition, structure and history of refractory material.

Rare gas studies of the galactic cosmic ray irradiation history of lunar rocks

1972 ◽  
Vol 36 (3) ◽  
pp. 269-301 ◽  
Author(s):  
J.C Huneke ◽  
F.A Podosek ◽  
D.S Burnett ◽  
G.J Wasserburg
Keyword(s):  
Cosmic Ray ◽  
Rare Gas ◽  
Lunar Rocks ◽  
History Of ◽  
Galactic Cosmic Ray

scholarly journals The Galactic cosmic ray intensity at the evolving Earth and young exoplanets

2020 ◽  
Author(s):  
Donna Rodgers-Lee ◽  
Aline Vidotto ◽  
Andrew Taylor ◽  
Paul Rimmer ◽  
Turlough Downes
Keyword(s):  
Solar Wind ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
The Sun ◽  
Cosmic Ray Intensity ◽  
Chemical Signature ◽  
Exoplanetary Systems ◽  
Life On Earth ◽  
Galactic Cosmic Ray

<p>Cosmic rays may have contributed to the start of life on Earth. Cosmic rays also influence and contribute to atmospheric electrical circuits, cloud cover and biological mutation rates which are important for the characterisation of exoplanetary systems. The flux of Galactic cosmic rays present at the time when life is thought to have begun on the young Earth or in other young exoplanetary systems is largely determined by the properties of the stellar wind. </p> <p>The spectrum of Galactic cosmic rays that we observe at Earth is modulated, or suppressed, by the magnetised solar wind and thus differs from the local interstellar spectrum observed by Voyager 1 and 2 outside of the solar system. Upon reaching 1au, Galactic cosmic rays subsequently interact with the Earth’s magnetosphere and some of their energy is deposited in the upper atmosphere. The properties of the solar wind, such as the magnetic field strength and velocity profile, evolve with time. Generally, young solar-type stars are very magnetically active and are therefore thought to drive stronger stellar winds. </p> <p>Here I will present our recent results which simulate the propagation of Galactic cosmic rays through the heliosphere to the location of Earth as a function of the Sun's life, from 600 Myr to 6 Gyr, in the Sun’s future. I will specifically focus on the flux of Galactic cosmic rays present at the time when life is thought to have started on Earth (~1 Gyr). I will show that the intensity of Galactic cosmic rays which reached the young Earth, by interacting with the solar wind, would have been greatly reduced in comparison to the present day intensity. I will also discuss the effect that the Sun being a slow/fast rotator would have had on the flux of cosmic rays reaching Earth at early times in the solar system's life.</p> <p>Despite the importance of Galactic cosmic rays, their chemical signature in the atmospheres’ of young Earth-like exoplanets may not be observable with instruments in the near future. On the other hand, it may instead be possible to detect their chemical signature by observing young warm Jupiters. Thus, I will also discuss the HR 2562b exoplanetary system as a candidate for observing the chemical signature of Galactic cosmic rays in a young exoplanetary atmosphere with upcoming missions such as JWST.</p>

scholarly journals THz and mid-IR spectroscopy of interstellar ice analogs: methyl and carboxylic acid groups

2014 ◽  
Vol 168 ◽  
pp. 461-484 ◽  
Author(s):  
S. Ioppolo ◽  
B. A. McGuire ◽  
M. A. Allodi ◽  
G. A. Blake
Keyword(s):  
Functional Groups ◽  
Solid Phase ◽  
Fundamental Problem ◽  
Individual Species ◽  
Complex Molecules ◽  
Interstellar Ice ◽  
Different Temperatures ◽  
History Of ◽  
Composition Structure ◽  
Complex Organic

A fundamental problem in astrochemistry concerns the synthesis and survival of complex organic molecules (COMs) throughout the process of star and planet formation. While it is generally accepted that most complex molecules and prebiotic species form in the solid phase on icy grain particles, a complete understanding of the formation pathways is still largely lacking. To take full advantage of the enormous number of available THz observations (e.g.,Herschel Space Observatory, SOFIA, and ALMA), laboratory analogs must be studied systematically. Here, we present the THz (0.3–7.5 THz; 10–250 cm−1) and mid–IR (400–4000 cm−1) spectra of astrophysically-relevant species that share the same functional groups, including formic acid (HCOOH) and acetic acid (CH3COOH), and acetaldehyde (CH3CHO) and acetone ((CH3)2CO), compared to more abundant interstellar molecules such as water (H2O), methanol (CH3OH), and carbon monoxide (CO). A suite of pure and mixed binary ices are discussed. The effects on the spectra due to the composition and the structure of the ice at different temperatures are shown. Our results demonstrate that THz spectra are sensitive to reversible and irreversible transformations within the ice caused by thermal processing, suggesting that THz spectra can be used to study the composition, structure, and thermal history of interstellar ices. Moreover, the THz spectrum of an individual species depends on the functional group(s) within that molecule. Thus, future THz studies of different functional groups will help in characterizing the chemistry and physics of the interstellar medium (ISM).

scholarly journals Proton Irradiation of Centaur, Kuiper Belt, and Oort Cloud Objects at Plasma to Cosmic Ray Energy

2003 ◽  
Vol 92 (1-4) ◽  
pp. 261-277 ◽  
Author(s):  
John F. Cooper ◽  
Eric R. Christian ◽  
John D. Richardson ◽  
Chi Wang
Keyword(s):  
Proton Irradiation ◽  
Kuiper Belt ◽  
Cosmic Ray ◽  
Oort Cloud

scholarly journals Valine Radiolysis by H+, He+, N+, and S15+ MeV Ions

2020 ◽  
Vol 21 (5) ◽  
pp. 1893 ◽  
Author(s):  
Cíntia A. P. da Costa ◽  
Gabriel S. Vignoli Muniz ◽  
Philippe Boduch ◽  
Hermann Rothard ◽  
Enio F. da Silveira
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Absorbed Dose ◽  
Cosmic Ray ◽  
Ethanol Solution ◽  
Stopping Power ◽  
Fast Ions ◽  
Space Data ◽  
Galactic Cosmic Ray ◽  
Complex Organic

Radiolysis of biomolecules by fast ions has interest in medical applications and astrobiology. The radiolysis of solid D-valine (0.2–2 μm thick) was performed at room temperature by 1.5 MeV H+, He+, N+, and 230 MeV S15+ ion beams. The samples were prepared by spraying/dropping valine-water-ethanol solution on ZnSe substrate. Radiolysis was monitored by infrared spectroscopy (FTIR) through the evolution of the intensity of the valine infrared 2900, 1329, 1271, 948, and 716 cm−1 bands as a function of projectile fluence. At the end of sample irradiation, residues (tholins) presenting a brownish color are observed. The dependence of the apparent (sputtering + radiolysis) destruction cross section, σd, on the beam stopping power in valine is found to follow the power law σd = aSen, with n close to 1. Thus, σd is approximately proportional to the absorbed dose. Destruction rates due to the main galactic cosmic ray species are calculated, yielding a million year half-life for solid valine in space. Data obtained in this work aim a better understanding on the radioresistance of complex organic molecules and formation of radioproducts.

Simulation of the Galactic Cosmic Ray Shadow of the Sun

2017 ◽  
Vol 34 (12) ◽  
pp. 129601
Author(s):  
Mohsin Saeed ◽  
Min Zha ◽  
Zhen Cao
Keyword(s):  
Cosmic Ray ◽  
The Sun ◽  
Galactic Cosmic Ray

Galileo Unbound

2018 ◽  
Author(s):  
David D. Nolte
Keyword(s):  
Free Fall ◽  
The Sun ◽  
Quantum Field ◽  
Many Worlds ◽  
Quantum Particles ◽  
Light Rays ◽  
History Of ◽  
And Control ◽  
The Universe ◽  
Insight Into

Galileo Unbound: A Path Across Life, The Universe and Everything traces the journey that brought us from Galileo’s law of free fall to today’s geneticists measuring evolutionary drift, entangled quantum particles moving among many worlds, and our lives as trajectories traversing a health space with thousands of dimensions. Remarkably, common themes persist that predict the evolution of species as readily as the orbits of planets or the collapse of stars into black holes. This book tells the history of spaces of expanding dimension and increasing abstraction and how they continue today to give new insight into the physics of complex systems. Galileo published the first modern law of motion, the Law of Fall, that was ideal and simple, laying the foundation upon which Newton built the first theory of dynamics. Early in the twentieth century, geometry became the cause of motion rather than the result when Einstein envisioned the fabric of space-time warped by mass and energy, forcing light rays to bend past the Sun. Possibly more radical was Feynman’s dilemma of quantum particles taking all paths at once—setting the stage for the modern fields of quantum field theory and quantum computing. Yet as concepts of motion have evolved, one thing has remained constant, the need to track ever more complex changes and to capture their essence, to find patterns in the chaos as we try to predict and control our world.

Sign in / Sign up

Export Citation Format

Share Document