1
Q
Neutron Degeneracy Pressure
A
.
2
Q
Chandrasekhar limit
A
.
3
Q
active galactic nucleus (AGN)
A
.
4
Q
Hawking Radiation
A
.
5
Q
Event horizon
A
.
6
Q
Kugelblitz
A
.
7
Q
.
A
The Interstellar Medium
8
Q
Large body that collided with Earth to create Moon
A
Theya
9
Q
.
A
Entangled Universe
10
Q
LXCC
A
Cold Clouds (Interstellar clouds)
11
Q
.
A
James Webb Telescope
12
Q
What is the Angular correlation function?
A
A statistical measure of how the angle between two points in the sky correlates with their spatial separation.
It helps in analyzing the distribution of galaxies and cosmic structures.
13
Q
Define Angular diameter.
A
The apparent size of an object as seen from a specific point, measured in angular units.
Important in determining the size of astronomical objects relative to their distance.
14
Q
What is Angular diameter distance?
A
A distance measure used in cosmology to relate the angular size of an object to its physical size.
It accounts for the expansion of the universe.
15
Q
What does Atmospheric circulation of exoplanets refer to?
A
The large-scale movement of air within an exoplanet’s atmosphere that affects its climate and weather patterns.
This can influence habitability and the potential for life.
16
Q
What is Bondi accretion?
A
A theoretical model describing the process by which a celestial object accumulates mass from a surrounding medium.
Often applied in astrophysical contexts like black holes and neutron stars.
17
Q
Explain Bondi–Hoyle–Lyttleton accretion.
A
A model of accretion that accounts for the relative motion between a celestial body and the medium from which it is accreting.
Important for understanding how stars gain mass in dynamic environments.
18
Q
Define Bonnor–Ebert mass.
A
The maximum mass of a spherical cloud of gas in hydrostatic equilibrium against gravitational collapse.
Crucial for understanding star formation processes.
19
Q
What is the Chandrasekhar–Fermi method?
A
A technique used to estimate magnetic field strengths in astrophysical contexts by analyzing the motions of gas clouds.
It combines concepts of magnetohydrodynamics and turbulence.
20
Q
What does Chandrasekhar’s variational principle relate to?
A
A method in astrophysics for determining the stability of stellar structures by minimizing energy.
It is essential in studies of stellar equilibrium and stability.
21
Q
What is Chandrasekhar’s white dwarf equation?
A
An equation that describes the relationship between the mass and radius of a white dwarf star.
It is a fundamental result in the study of stellar evolution.
22
Q
Define Clumping factor.
A
A measure of the degree to which matter is clumped together in a given volume, often used in cosmological contexts.
Important for understanding galaxy formation and structure.
23
Q
What is the Darwin–Radau equation?
A
An equation used in celestial mechanics to describe the motion of bodies under mutual gravitational attraction.
It is particularly relevant in the study of planetary systems.
24
Q
What does De Sitter space refer to?
A
A solution to Einstein’s field equations of general relativity that describes a universe with a positive cosmological constant.
It models an expanding universe and is significant in cosmology.
25
What is De Vaucouleurs's law?
A mathematical expression describing the brightness profile of elliptical galaxies.
## Footnote
It provides insight into the structure and formation of galaxies.
26
What does Dermott's law describe?
A law related to the evolution of orbits in celestial mechanics, particularly for systems with multiple bodies.
## Footnote
It aids in understanding orbital dynamics.
27
What is Dirichlet's ellipsoidal problem?
A problem in classical mechanics concerning the equilibrium of a rotating, homogeneous ellipsoidal body under gravity.
## Footnote
Important for modeling celestial bodies' shapes and rotations.
28
What is the Double Fourier sphere method?
A mathematical technique used in astrophysics to analyze light from celestial objects through Fourier transforms.
## Footnote
It assists in imaging and understanding complex astronomical data.
29
Define Galaxy effective radius.
The radius within which half of a galaxy's total light is emitted.
## Footnote
Useful for characterizing the size and brightness distribution of galaxies.
30
What is the Einasto profile?
A mathematical function describing the density profile of dark matter halos in cosmology.
## Footnote
It provides a better fit for observational data compared to other profiles.
31
What does Epicyclic frequency refer to?
The frequency at which a star moves in a circular orbit around the center of a galaxy, influenced by the galaxy's gravitational field.
## Footnote
It is a key concept in the study of galactic dynamics.
32
What is the Faber–Jackson relation?
An empirical relationship between the luminosity of elliptical galaxies and their velocity dispersion.
## Footnote
It helps in understanding the dynamics and evolution of galaxies.
33
Define Fried parameter.
A measure used in cosmology to describe the curvature of space in a Friedmann-Lemaître-Robertson-Walker universe.
## Footnote
It is essential for understanding the geometry of the universe.
34
What is Gauss's method?
A numerical method for approximating solutions to problems in astronomy and physics, based on Gaussian functions.
## Footnote
It is widely used in various applications, including data analysis.
35
Define Hapke parameters.
Parameters used in modeling the scattering of light by planetary surfaces, particularly in remote sensing.
## Footnote
They are crucial for interpreting data from planetary missions.
36
What does Hellings-Downs curve describe?
The relationship between the amplitude of gravitational waves and their frequency as predicted by general relativity.
## Footnote
It is important for understanding gravitational wave signals.
37
What is the Hill sphere?
The region around a celestial body where it dominates the gravitational attraction of satellites.
## Footnote
It defines the area where a body can retain objects in orbit.
38
What does Hubble–Reynolds law relate to?
A relationship connecting the properties of galaxies, including their distance and velocity, to the expansion of the universe.
## Footnote
It is a key aspect of modern cosmology.
39
What is Hubble's law?
The observation that the farther away a galaxy is, the faster it is receding from us.
## Footnote
It supports the theory of an expanding universe.
40
What is the Initial mass function?
A distribution that describes the initial mass distribution of stars in a population.
## Footnote
It is fundamental for understanding star formation and evolution.
41
Define Jacobi ellipsoid.
An ellipsoidal shape that a rotating body adopts in equilibrium under its own gravity.
## Footnote
Important in the study of celestial mechanics and planetary shapes.
42
What is the Jaffe profile?
A mathematical model used to describe the density distribution of galaxies and dark matter halos.
## Footnote
It helps in fitting observational data for galaxy structures.
43
What do Jeans equations describe?
Equations that govern the dynamical behavior of star clusters and galaxies under gravity.
## Footnote
They are essential for understanding stellar dynamics.
44
What are Kepler's laws of planetary motion?
Three laws that describe the motion of planets around the sun: elliptical orbits, equal areas in equal times, and a relationship between orbital period and distance.
## Footnote
These laws form the foundation of classical mechanics in astronomy.
45
What does Kramers' opacity law describe?
A law relating to the opacity of a medium, particularly in the context of stellar atmospheres and radiation transfer.
## Footnote
It is important for understanding stellar evolution and energy transport.
46
What is the Leonard–Merritt mass estimator?
A method for estimating the mass of galaxies based on the kinematic properties of stars or gas within them.
## Footnote
It helps in determining the mass distribution in galaxies.
47
Define Luminosity distance.
A measure of distance that relates the apparent brightness of an object to its intrinsic luminosity.
## Footnote
It is crucial for understanding the distance scale in cosmology.
48
What is the Luminosity function (astronomy)?
A distribution function that describes the number density of astronomical objects as a function of their luminosity.
## Footnote
Important for understanding the population of stars and galaxies.
49
What does the M–sigma relation describe?
The relationship between the mass of a supermassive black hole and the velocity dispersion of stars in the galaxy core.
## Footnote
This relation provides insights into the co-evolution of galaxies and black holes.
50
Define Mean motion.
The average angular speed of a celestial body in its orbit, usually measured in degrees or radians per unit time.
## Footnote
It is a fundamental concept in orbital mechanics.
51
What is the Minnaert function?
A mathematical function used to describe the brightness of planetary surfaces as a function of phase angle.
## Footnote
Useful in remote sensing and planetary studies.
52
What does Moffat distribution refer to?
A mathematical function describing the intensity profile of light from celestial objects, particularly in astrophysical contexts.
## Footnote
It is often used in modeling the brightness of galaxies.
53
Define Momentum compaction.
A measure of how much the momentum of a system is concentrated in a given volume.
## Footnote
It is important in studies of dynamical systems and astrophysical processes.
54
What is the Odd number theorem?
A theorem related to the distribution of odd numbers in certain mathematical contexts, often applied in combinatorial problems.
## Footnote
It has implications in various fields, including number theory.
55
What does Planetary equilibrium temperature refer to?
The temperature at which a planet's energy absorbed from its star equals the energy it radiates back into space.
## Footnote
It is a key factor in assessing a planet's climate and potential habitability.
56
Define Plate scale.
The ratio of the distance on a photographic plate to the corresponding distance in the observed object.
## Footnote
It is important in the calibration of astronomical images.
57
What is the Plummer model?
A model used to describe the distribution of mass in star clusters, characterized by a specific density profile.
## Footnote
It is useful for simulating star cluster dynamics.
58
What does Press–Schechter formalism describe?
A method used in cosmology to predict the mass function of dark matter halos based on initial density fluctuations.
## Footnote
It is crucial for understanding structure formation in the universe.
59
What is Relaxation (physics)?
The process by which a system returns to equilibrium after being disturbed, particularly in the context of stellar dynamics.
## Footnote
It helps in understanding the long-term evolution of star clusters.
60
What is the Roche limit?
The minimum distance at which a celestial body can approach another body without being torn apart by tidal forces.
## Footnote
Important in understanding satellite formation and planetary rings.
61
Define S-factor.
A quantity used in nuclear astrophysics to describe the probability of fusion reactions occurring at low energies.
## Footnote
It is significant for understanding nucleosynthesis in stars.
62
What is the Sérsic profile?
A mathematical function used to describe the light profile of galaxies, generalizing the de Vaucouleurs law.
## Footnote
It is widely used in morphological studies of galaxies.
63
What does Sheth–Tormen approximation refer to?
An approximation used to describe the mass function of dark matter halos, taking into account the effects of non-Gaussian initial conditions.
## Footnote
It is relevant for structure formation theories.
64
What is the Sigma-D relation?
A correlation between the surface brightness and the central density of galaxies, often used in galactic dynamics studies.
## Footnote
It provides insights into galaxy formation and evolution.
65
Define Singular isothermal sphere profile.
A model used to describe the density distribution of dark matter in a spherical halo, characterized by a constant central density.
## Footnote
It is important in gravitational lensing studies.
66
What is the Small-angle approximation?
An approximation used in physics and astronomy when angles are small enough that their sine and tangent can be approximated by the angle itself.
## Footnote
It simplifies calculations in many contexts.
67
What does Source function refer to?
A function that describes the emission of radiation from a medium, often used in the context of radiative transfer.
## Footnote
It is critical for understanding astrophysical processes like star formation.
68
What is the Spectral index?
A measure of the rate of change of the flux density of an astronomical source with frequency.
## Footnote
It is used to classify sources and understand their physical processes.
69
What does Stellar dynamics study?
The study of the motion and gravitational interactions of stars within galaxies and star clusters.
## Footnote
It is essential for understanding the structure and evolution of stellar systems.
70
What is the Stumpff function?
A mathematical function used in celestial mechanics to solve problems involving orbital motion and time.
## Footnote
It is particularly useful in computing spacecraft trajectories.
71
What is the Three-body problem?
A problem in celestial mechanics that involves predicting the motion of three celestial bodies interacting with each other gravitationally.
## Footnote
It is a classic problem with no general solution.
72
Define Tisserand's parameter.
A quantity used to characterize the dynamics of a small body in relation to a larger body, such as a planet.
## Footnote
It is important in studies of comets and asteroids.
73
What is True anomaly?
The angle between the direction of periapsis and the current position of a body in its orbit, measured at the focus of the ellipse.
## Footnote
It is crucial for defining the position of an orbiting body.
74
What does True longitude refer to?
The angular distance of a body in its orbit from a reference direction, typically the vernal equinox, measured in the orbital plane.
## Footnote
It is used in celestial navigation and orbital mechanics.
75
What is the Umov effect?
The phenomenon where the intensity of light scattered by particles is affected by the direction of the incident light.
## Footnote
It has implications in atmospheric studies and remote sensing.
76
Define Universal variable formulation.
A mathematical approach used to simplify the equations of motion of celestial bodies, allowing for a unified treatment of different orbits.
## Footnote
It is useful in astrodynamics for trajectory calculations.
77
What is the Van Cittert–Zernike theorem?
A theorem in optics that relates the visibility of an object to its spatial coherence and the distribution of its light source.
## Footnote
It has applications in radio astronomy and imaging.
78
What is Velocity dispersion?
A measure of the range of velocities of stars in a galaxy or star cluster, often used to infer mass.
## Footnote
It is important for understanding the dynamics of stellar systems.
79
What does the Virbhadra–Ellis lens equation describe?
An equation used in gravitational lensing to relate the positions and distances of the lensing mass and background source.
## Footnote
It is critical for interpreting lensing observations in astronomy.
80
What is the Virial theorem?
A theorem relating the average kinetic energy of a system to its average potential energy, often applied in astrophysics.
## Footnote
It is useful for analyzing the stability of star clusters and galaxies.
81
Define Vis-viva equation.
An equation that relates the speed of an orbiting body to its distance from a focal point and the semi-major axis of its orbit.
## Footnote
It is fundamental in celestial mechanics.
82
What does Von Zeipel theorem describe?
A theorem that describes the distribution of brightness in rotating stars, indicating that equatorial regions are brighter due to centrifugal forces.
## Footnote
It is important for understanding stellar structure and evolution.
Sam’s Astronomy
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