Astronomical spectroscopy is a technique used in astronomy to analyze the light emitted, absorbed, or scattered by objects in space, such as stars, galaxies, and nebulae. It involves breaking down this light into its constituent wavelengths, creating a spectrum that reveals a wealth of information about the source of the light. Key aspects of astronomical spectroscopy include: 1. **Spectra Types**: The resulting spectrum can be continuous, emission, or absorption spectra, each providing different insights.
Asteroid spectral classes are classifications used to categorize asteroids based on their reflectance spectra, which is the way they reflect sunlight. These spectral characteristics provide insights into their composition, structure, and sometimes their origins. The most common asteroid spectral classes are based on the taxonomy developed by the asteroid community, primarily the Tholen and Bus-DeMeo classifications.
Exoplanets detected by radial velocity, also known as the Doppler method or the radial velocity method, is a technique used to identify exoplanets by observing the gravitational influence they have on their host stars. This method takes advantage of the Doppler effect, where the light emitted by a star shifts in wavelength depending on its motion relative to an observer.
Asteroid spectral types are classifications of asteroids based on their reflectance spectra, which is the way they reflect light across different wavelengths. These spectral types help astronomers understand the composition, surface properties, and origins of asteroids. Different spectral types correspond to different mineralogical and chemical compositions. The most commonly used spectral classifications for asteroids include: 1. **C-type (Carbonaceous)**: These are the most common type, making up about 75% of all known asteroids.
The Balmer jump refers to a specific phenomenon observed in the spectra of hydrogen or hydrogen-like atoms, where there is a significant discontinuity in the intensity of the spectral lines in the Balmer series. The Balmer series consists of the spectral lines corresponding to electron transitions from higher energy levels (n ≥ 3) down to the second energy level (n = 2) in hydrogen.
In the context of probability and statistics, a **binary mass function** generally refers to a probability mass function (PMF) for a discrete random variable that can take only two possible outcomes, typically coded as 0 and 1. This type of distribution is often used to model binary events, such as a coin toss (heads or tails) or a success/failure scenario in Bernoulli trials.
The term "calcium triplet" typically refers to a specific feature observed in the spectrum of stars, particularly in the ultraviolet and visible light ranges. This feature consists of three closely spaced absorption lines associated with ionized calcium (Ca II). The calcium triplet lines are prominent in the spectra of late-type stars, especially red giants, and are most commonly observed in the following wavelengths: 1. **H and K lines** (3968 Å and 3934 Å) 2.
Collisional excitation is a process in which an atom or molecule absorbs energy during a collision with a particle, such as another atom, molecule, or electron. This energy transfer can promote an electron within the atom or molecule to a higher energy state, or excited state. Here's how it works: 1. **Encounter**: During a collision, kinetic energy from the colliding particle (which can be a gas particle or an electron) is transferred to the target atom or molecule.
A Damped Lyman-alpha system (DLA) is a type of astronomical object observed in the spectra of distant quasars and galaxies. It is characterized by a strong absorption feature in the Lyman-alpha transition of hydrogen (at a wavelength of 121.6 nm) due to neutral hydrogen gas in the intervening medium.
The Doppler parameter, often denoted as \( \beta \), is a dimensionless quantity used to describe the relativistic effects of motion in the context of Doppler shift, particularly in astrophysics and cosmology. It is defined as: \[ \beta = \frac{v}{c} \] where: - \( v \) is the relative velocity of an object moving away from or towards an observer, - \( c \) is the speed of light in a vacuum.
Doppler spectroscopy, also known as Doppler radial velocity spectroscopy, is a technique used primarily in astronomy to detect and characterize exoplanets and other celestial bodies. It leverages the Doppler effect, which describes the change in frequency or wavelength of light (or other waves) in relation to an observer moving relative to the source of that light.
Doubly ionized oxygen refers to an oxygen atom that has lost two of its electrons, resulting in a cation with a charge of +2. This can be represented chemically as O²⁺. In this state, the oxygen atom is in a highly energetic condition and is less stable compared to neutral oxygen or singly ionized oxygen (O⁺).
H-alpha is a specific wavelength of light that is emitted by hydrogen atoms when their electrons transition from the third energy level to the second energy level. This transition produces light at a wavelength of 656.28 nanometers, which falls within the red part of the visible spectrum.
Lyman-alpha blobs are large, glowing regions of hydrogen gas that emit strong Lyman-alpha radiation, which corresponds to the wavelength of light emitted by neutral hydrogen atoms when an electron transitions from the second energy level to the ground state. These blobs are typically found in the early universe, often associated with actively forming galaxies or regions with significant star formation.
The Lyman-alpha forest refers to a series of absorption lines in the spectra of distant quasars, primarily produced by intervening clouds of hydrogen gas in the intergalactic medium. When light from a quasar passes through these clouds, certain wavelengths of that light are absorbed due to the Lyman-alpha transition of hydrogen, which corresponds to a specific wavelength of 121.6 nanometers in the ultraviolet region of the spectrum.
A Multi-Object Spectrometer (MOS) is an astronomical instrument designed to obtain spectra from multiple astronomical objects simultaneously. Instead of focusing on a single object (as with traditional spectrometers), a MOS can gather information from many different targets within a single observation. This capability is particularly valuable for large surveys and studies of distant galaxies, star clusters, and other celestial phenomena, as it allows for efficient data collection across a wide field of view.
The Pickering series refers to a series of spectral lines that are observed in the emission or absorption spectra of certain elements, particularly hydrogen. These lines arise from electronic transitions of the hydrogen atom, where electrons move between different energy levels. The Pickering series specifically refers to transitions where an electron falls from a higher energy level (n ≥ 6) down to the n=5 energy level. It is named after the British astronomer William Pickering, who studied these spectral lines.
The Rossiter–McLaughlin effect is an astrophysical phenomenon observed during transits of exoplanets, specifically when a planet passes in front of its host star from our viewpoint. This effect occurs because the planet partially blocks the star's light and causes a distortion in the Doppler shift of the star's light as seen from Earth. When a planet transits, it blocks different parts of the star's surface as it moves across it.
SLIM can refer to various concepts depending on the context. Here are a few possibilities: 1. **SLIM (Software Library for Image Manipulation)**: A library or tool used for manipulating images in different programming environments. 2. **SLIM (Statistical Learning and Inference Method)**: A method or approach in statistics and data science for making inferences based on statistical models.
SOXS is an acronym that can refer to different things depending on the context. Here are a couple of common usages: 1. **SOXS (Soxhlet Extraction)**: In scientific and analytical contexts, SOXS may refer to the Soxhlet extraction method, which is used to extract lipids or other compounds from a solid sample through continuous solvent extraction.
Slitless spectroscopy is a technique used in the field of astronomical spectroscopy that allows for the observation and analysis of light from celestial objects without the use of a physical slit to restrict the incoming light. Instead, this method employs a dispersive element, like a prism or grating, to separate light into its constituent wavelengths over a wide field of view.
A spectral atlas is a collection of spectra representing various physical substances, typically used in fields like spectroscopy, astronomy, and chemistry. These atlases serve as reference materials for identifying and analyzing the spectral lines emitted or absorbed by different elements and compounds. In the context of astronomical applications, a spectral atlas may contain the spectral lines of stars, galaxies, and other celestial objects, allowing astronomers to determine their composition, temperature, density, mass, distance, luminosity, and relative motion.
Spectral imaging is a technique that captures and analyzes the spectral characteristics of light reflected or emitted from objects. Unlike traditional imaging methods that primarily capture intensity information in the visible spectrum, spectral imaging gathers information across a wide range of wavelengths, including ultraviolet, visible, and infrared light.
The Stebbins–Whitford effect refers to a phenomenon observed in the field of astronomy, specifically in the context of star formation and the evolutionary pathways of galaxies. It describes the relationship between the metallicity (the abundance of elements heavier than hydrogen and helium) of stars and their distance from the galactic center. In general, stars in the central regions of a galaxy tend to have higher metallicities compared to those located further out.
The Wilson–Bappu effect is an astronomical phenomenon observed in the field of stellar spectroscopy, particularly concerning the stars designated as Cepheid variables. It describes a correlation between the period of pulsation of Cepheid variables and their mean luminosity (brightness). Essentially, this means that the longer the period of pulsation of a Cepheid variable star, the more luminous it is. This relationship is crucial for distance measurement in astronomy.
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