scholarly journals f (T) gravity: effects on astronomical observations and Solar system experiments and upper bounds

2013 ◽  
Vol 433 (4) ◽  
pp. 3584-3589 ◽  
Author(s):  
Yi Xie ◽  
Xue-Mei Deng
Keyword(s):  
Solar System ◽  
Upper Bounds ◽  
Astronomical Observations ◽  
Gravity Effects

Optical properties of poly-HCN and their astronomical applications

1994 ◽  
Vol 72 (3) ◽  
pp. 678-694 ◽  
Author(s):  
Bishun N. Khare ◽  
Carl Sagan ◽  
W. Reid Thompson ◽  
Edward T. Arakawa ◽  
Caroline Meisse ◽  
...  
Keyword(s):  
Solar System ◽  
Optical Constants ◽  
Near Infrared ◽  
Quantitative Comparison ◽  
Spectroscopic Techniques ◽  
Vacuum Deposition ◽  
Organic Residues ◽  
Specific Test ◽  
Astronomical Observations ◽  
Standard Models

Matthews (1992) has proposed that HCN "polymer" is ubiquitous in the solar system. We apply vacuum deposition and spectroscopic techniques previously used on synthetic organic heteropolymers (tholins), kerogens, and meteoritic organic residues to the measurement of the optical constants of poly-HCN in the wavelength range 0.05–40 µm. These measurements allow quantitative comparison with spectrophotometry of organic-rich bodies in the outer solar system. In a specific test of Matthews' hypothesis, poly-HCN fails to match the optical constants of the haze of the Saturnian moon, Titan, in the visible and near-infrared, derived from astronomical observations and standard models of the Titan atmosphere. In contrast, a tholin produced from a simulated Titan atmosphere matches within the probable errors. Poly-HCN is much more N-rich than Titan tholin.

scholarly journals Time-Scales of the s Process: from Minutes to Ages

2009 ◽  
Vol 26 (3) ◽  
pp. 209-216 ◽  
Author(s):  
F. Käppeler ◽  
S. Bisterzo ◽  
R. Gallino ◽  
M. Heil ◽  
M. Pignatari ◽  
...  
Keyword(s):  
Solar System ◽  
Time Scales ◽  
Cross Sections ◽  
70Th Anniversary ◽  
Astronomical Observations ◽  
Comprehensive Picture ◽  
Stimulation Of

AbstractThe time scales in the s process appears to be an approriate aspect to discuss at the occasion of Roberto's 70th anniversary, the more as this subject has been repeatedly addressed during the 20 years of collaboration between Torino and Karlsruhe. The two chronometers presented in this text were selected to illustrate the intense mutual stimulation of both groups. Based on a reliable set of accurate stellar (n, γ) cross sections determined mostly at FZK, the Torino group succeeded to develop a comprehensive picture of the various s-process scenarios, which are most valuable for understanding the composition of the solar system as well as for the interpretation of an increasing number of astronomical observations.

scholarly journals The first results of meteor phenomena observations using automated video-spectral meteor patrol of V.N. Karazin Kharkiv National University

2019 ◽  
pp. 36-41
Author(s):  
А. Golubaev ◽  
A. Mozgova
Keyword(s):  
Remote Sensing ◽  
Solar System ◽  
Video Camera ◽  
Meteor Shower ◽  
Educational Process ◽  
Astronomical Observations ◽  
National University ◽  
First Results ◽  
Observational Station ◽  
Scientific Base

In 2018, an observation complex (automatic video-spectral meteor patrol (AVSMP)) was designed and constructed at the Institute of Astronomy, V.N. Karazin Kharkiv National University, for obtaining kinematic and physical characteristics of meteor bodies and their spectra. Cameras were tested in astronomical observations mode with the aim to identify the technical capabilities of the device. This paper presents some of the first results of observations conducted with the help of AVSMP. The created observation complex is intended to expand the material, scientific, as well as educational and scientific base of the Institute of Astronomy. It will be used in the educational process at the Department of Astronomy and Space Informatics of V.N. Karazin KhNU, during practical and laboratory classes, performing bachelor’s and master’s works and developing the newest methods of remote sensing of astronomical objects of the Solar system. In August 2019, the first baseline observations of Perseid’s meteor shower were conducted using AVSMP. At Chuguev observational station of the Institute of Astronomy, where the complex is located, 225 video fragments with meteors in integral light and 98 videos with spectra of meteors were recorded. In Kharkiv, 132 video fragments with meteors in integral light were recorded by the secondary video camera. Of the obtained observation footage, 98 meteors recorded in the integral light are basic, and another 40 video fragments with spectra of meteors have corresponding basic observations in the integral light.

V. Observations of a comet, remarks on the construction of its different parts

1812 ◽  
Vol 102 ◽  
pp. 115-143 ◽  
Keyword(s):  
Solar System ◽  
Astronomical Observations ◽  
Different Parts ◽  
Selection Of

The comet which has lately visited the solar system has moved in an orbit very favourably situated for astronomical observations. I have availed myself of this circumstance, and have examined all the parts of it with a scrutinizing attention, by telescopes of every degree of requisite light, distinctness, and power. The observations I have made have been so numerous, and so often repeated, that I shall only give a selection of such as were made under the most favourable circumstances, and which will serve to ascertain the most interesting particulars relating to the construction of the comet.

scholarly journals HUGE QUANTUM GRAVITY EFFECTS IN THE SOLAR SYSTEM

2010 ◽  
Vol 19 (14) ◽  
pp. 2271-2274 ◽  
Author(s):  
DON N. PAGE
Keyword(s):  
Solar System ◽  
Quantum Gravity ◽  
Planetary Motion ◽  
The Sun ◽  
Classical Chaos ◽  
Gravity Effects ◽  
The Galaxy

Normally one thinks of the motion of the planets around the Sun as a highly classical phenomenon, so that one can neglect quantum gravity in the solar system. However, classical chaos in the planetary motion amplifies quantum uncertainties so that they become very large, giving huge quantum gravity effects. For example, evidence suggests that Uranus may eventually be ejected from the solar system, but quantum uncertainties would make the direction at which it leaves almost entirely uncertain, and the time of its exit uncertain by about one quadrillion years. For a time a quadrillion years from now, there are huge quantum uncertainties whether Uranus will be within the solar system, within the galaxy, or even within causal contact of the galaxy.

Presolar Grains

2021 ◽  
Author(s):  
Nan Liu
Keyword(s):  
Solar System ◽  
Nuclear Reaction ◽  
Reaction Rates ◽  
Astronomical Observations ◽  
Presolar Grains ◽  
Isotope Data ◽  
Stellar Nucleosynthesis ◽  
Different Types ◽  
Extraterrestrial Materials ◽  
Asteroids And Comets

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article. Presolar grains are dust produced by stars that died before the formation of the Earth’s solar system. Stardust grains condense out of cooling gas lost via stellar winds from the surface of low-mass stars and stellar explosions and become a constituent of interstellar medium (ISM). About 4.6 Ga, a molecular cloud in the ISM collapsed to form the solar system, during which some primordial stardust grains from the ISM survived and were incorporated into small bodies formed in the early solar system. Some of these small solar system bodies, including asteroids and comets, escaped planet formation and have remained minimally altered, thus preserving their initially incorporated presolar grains. Fragments of asteroids and comets are collected on Earth as interplanetary dust particles (IDPs) and meteorites. Presolar grains have been found in primitive IDPs and chondrites—stony meteorites that have not been modified by either melting or differentiation of their parent bodies. Presolar grains, typically less than a few μm, are identified in primitive extraterrestrial materials by their unique isotopic signatures, revealing the effects of galactic chemical evolution (GCE), stellar nucleosynthesis, and cosmic ray exposure. Comparisons of presolar grain isotope data with stellar observations and nucleosynthesis model calculations suggest that presolar grains were dominantly sourced from asymptotic giant branch stars and core-collapse supernovae, although there are still ambiguities in assigning the type of star to some groups of grains. So far, various presolar phases have been identified such as corundum, olivine, and silicon carbide, reflecting diverse condensation environments in different types of stars. The abundances of different presolar phases in primitive extraterrestrial materials vary widely, ranging from a few percent for presolar silicates to a few parts per million for presolar oxides. Presolar grain studies rely on the synergy between astronomy, astrophysics, nuclear physics, and cosmochemistry. To understand the stellar sources of presolar grains, it is important to compare isotope data of presolar grains to astronomical observations for different types of stellar objects. When such astronomical observations are unavailable, stellar nucleosynthesis models must be relied upon, which require inputs of (a) initial stellar composition estimated based on solar system nuclide abundances, (b) stellar evolution models, and (c) nuclear reaction rates determined by theories and laboratory experiments. Once the stellar source of a group of presolar grains is ascertained, isotope information extracted from the grains can then be used to constrain stellar mixing processes, nuclear reaction rates, GCE, and the ISM residence times of the grains. In addition, crystal structures and chemical compositions of presolar grains can provide information to infer dust condensation conditions in their parent stars, while abundances of presolar grains in primitive chondrites can help constrain secondary processing experienced by the parent asteroids of their host chondrites. Since the discovery of presolar grains in meteorites in 1980s, a diverse array of information about stars and GCE has been gleaned by studying them. Technological advances will likely allow for the discovery of additional types of presolar grains and analysis of smaller, more typical presolar grains in the future.

scholarly journals Verlinde gravity effects on the orbits of the planets and the Moon in the Solar System

2020 ◽  
Vol 37 (13) ◽  
pp. 135007
Author(s):  
Youngsub Yoon ◽  
Luciano Ariel Darriba
Keyword(s):  
Solar System ◽  
The Moon ◽  
Gravity Effects
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