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Astronomy & Astrophysics
Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. The journal is run by a Board of Directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The main editors of A&A are the editor-in-chief,  Thierry Forveille (fr); the Letters editor-in-chief, João Alves; and the managing editor David Elbaz. The journal is published by EDP Sciences in 12 issues per year. With an impact factor of 5.802 (2020), A&A is one of the most important academic journals in its field. Several sections of the journal are available in Open Access, and the latest issue is also available for free online reading on the journal website.
  • 421
  • 09 Nov 2022
Topic Review
(6545) 1986 TR6
(6545) 1986 TR6, provisional designation 1986 TR6, is a Jupiter trojan from the Greek camp, approximately 53 kilometers (33 miles) in diameter. It was discovered on 5 October 1986, by Slovak astronomer Milan Antal at the Piwnice Astronomical Observatory in Poland. The dark D-type asteroid has a rotation period of 16.3 hours and belongs to the 90 largest Jupiter trojans. It has not been named since its numbering in September 1995.
  • 353
  • 09 Nov 2022
Topic Review
J/Psi Meson
The J/ψ (J/psi) meson /ˈdʒeɪ ˈsaɪ ˈmiːzɒn/ or psion is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium". The J/ψ is the most common form of charmonium, due to its spin of 1 and its low rest mass. The J/ψ has a rest mass of 3.0969 GeV/c2, just above that of the ηc (2.9836 GeV/c2), and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected. Its discovery was made independently by two research groups, one at the Stanford Linear Accelerator Center, headed by Burton Richter, and one at the Brookhaven National Laboratory, headed by Samuel Ting of MIT. They discovered they had actually found the same particle, and both announced their discoveries on 11 November 1974. The importance of this discovery is highlighted by the fact that the subsequent, rapid changes in high-energy physics at the time have become collectively known as the "November Revolution". Richter and Ting were awarded the 1976 Nobel Prize in Physics.
  • 1.2K
  • 09 Nov 2022
Topic Review
Thermodynamics of the Universe
The thermodynamics of the universe is dictated by which form of energy dominates it - relativistic particles which are referred to as radiation, or non-relativistic particles which are referred to as matter. The former are particles whose rest mass is zero or negligible compared to their energy, and therefore move at the speed of light or very close to it; the latter are particles whose kinetic energy is much lower than their rest mass and therefore move much slower than the speed of light. The intermediate case is not treated well analytically.
  • 936
  • 09 Nov 2022
Topic Review
Exoplanetology
Exoplanetology, or exoplanetary science, is an integrated field of astronomical science dedicated to the search for and study of exoplanets (extrasolar planets). It employs an interdisciplinary approach which includes astrobiology, astrophysics, astronomy, astrochemistry, astrogeology, geochemistry, and planetary science.
  • 2.0K
  • 09 Nov 2022
Topic Review
Spin-½
In quantum mechanics, spin is an intrinsic property of all elementary particles. All known fermions, the particles that constitute ordinary matter, have a spin of 1/2. The spin number describes how many symmetrical facets a particle has in one full rotation; a spin of 1/2 means that the particle must be rotated by two full turns (through 720°) before it has the same configuration as when it started. Particles having net spin 1/2 include the proton, neutron, electron, neutrino, and quarks. The dynamics of spin-1/2 objects cannot be accurately described using classical physics; they are among the simplest systems which require quantum mechanics to describe them. As such, the study of the behavior of spin-1/2 systems forms a central part of quantum mechanics.
  • 1.9K
  • 09 Nov 2022
Topic Review
Characterization of MXene's Terminations
MXene, 2D transition metal carbides, nitrides, and carbonitrides with a unique 2D structure, inspired a series of function applications related to energy storage and conversion, biometrics and sensing, lighting, purification, and separation. Its surface terminations are confined by the adjacent MXene layers, and form the 2D planar space with symmetrical surfaces, which is similar to a 2D nanoreactor that can be utilized and determined MXene’s function. Accurate characterization of MXene surface terminations is the prerequisite for studying the regulatory methods and the influence of properties and performance. Because the surface termination of MXene presents two-dimensional plane distribution and the collision probability of atoms, molecules, electrons, and optical signals is low. MXene prepared by chemical methods has certain impurity content. In addition, most surface terminations do not exist in a stable state, which leads to the difficulty of the accurate characterization of MXene surface terminations. At present, XPS, EDX, XAS and EELS are often used for qualitative and quantitative analysis of MXene surface terminations.
  • 1.5K
  • 09 Nov 2022
Topic Review
Jet Flavour Tagging
Jet Flavour Tagging briefly describes the main algorithms used to reconstruct heavy-flavour jets. Jet Substructure and Deep Tagging focuses on the identification of heavy-particle decay in boosted jets. These so-called tagger algorithms have a relevant role in physics studies since they allow researchers to successfully reconstruct and identify the particles that caused the jet and, in some cases, allow analyses that would otherwise be unfeasible.
  • 476
  • 09 Nov 2022
Topic Review
ADM Energy
The ADM formalism (named for its authors Richard Arnowitt, Stanley Deser and Charles W. Misner) is a Hamiltonian formulation of general relativity that plays an important role in canonical quantum gravity and numerical relativity. It was first published in 1959. The comprehensive review of the formalism that the authors published in 1962 has been reprinted in the journal General Relativity and Gravitation, while the original papers can be found in the archives of Physical Review.
  • 644
  • 08 Nov 2022
Topic Review
Space Apps
Space Apps is annual NASA's global hackathon, first held in April 2012, and serves as innovation incubation and civic engagement program. NASA and its partners put out challenges relating to current work for which space enthusiasts around the world of all backgrounds can develop innovative solutions (which can be more than just apps!), particularly focusing on use of NASA data and promoting education. The project, formerly run by NASA's Office of the Chief Information Officer, is part of NASA's Earth Science Mission Directorate and is a part of the Open Government Initiative founded under President Barack Obama "creating an unprecedented level of openness in Government." It also fulfills the United States’ commitments to the Open Government Partnership.
  • 233
  • 08 Nov 2022
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