BlackBody
This term describes the total amount of energy a star emits per second, often measured in watts or compared to the Sun's output.
What is luminosity?
This effect, used by astronomers to measure distances to nearby stars, relies on the apparent shift of an object against a distant background when observed from different positions.
What is parallax?
The transfer of radiation is governed by this fundamental equation, which describes how intensity changes along a path.
What is the radiative transfer equation?
Equilibrium temperature is reached when this energy absorbed by a planet equals the energy it radiates back into space.
What is stellar radiation?
The apparent brightness of a star, as seen from Earth, is measured using this system, where smaller numbers represent brighter objects.
What is the magnitude system?
This relationship explains how the apparent brightness of a star is determined by its total energy output and distance from the observer.
What is the relationship between flux and luminosity?
Parallax measurements for celestial objects are typically taken six months apart to maximize the baseline, which corresponds to this astronomical distance.
What is the distance of Earth's orbit around the Sun?
In radiative transfer, this term describes the reduction in the intensity of radiation as it passes through a medium due to absorption and scattering.
What is extinction?
The equilibrium temperature of a planet depends on its distance from its star, the star's luminosity, and this fraction of incident sunlight reflected back into space.
What is albedo?
The difference in brightness between two stars is calculated using a logarithmic scale, with a difference of five magnitudes corresponding to this factor in intensity.
What is a factor of 100?
This physicist is best known for his law describing the relationship between the temperature of a blackbody and the wavelength of its peak emission.
Who is Wilhelm Wien?
The parallax angle of a star is inversely proportional to its distance, expressed in these units for stellar distances.
What are parsecs?
This dimensionless measure, crucial in radiative transfer, indicates the relative importance of scattering and absorption in a medium.
What is the optical depth?
The equilibrium temperature calculation assumes that a planet behaves like this idealized body, which absorbs and emits radiation perfectly.
What is a blackbody?
The color of a star is determined by its temperature, with hotter stars appearing blue and cooler stars appearing red, following this law.
What is Wien's displacement law?
This law states that the total energy radiated per unit surface area of a blackbody is proportional to the fourth power of its temperature.
What is the Stefan-Boltzmann law?
The star with the largest parallax angle, and thus the closest star to Earth besides the Sun, is this one.
What is Proxima Centauri?
A medium with an optical depth much greater than one is described as this, meaning it strongly absorbs or scatters light passing through it.
What is optically thick?
Planets with significant atmospheres may have surface temperatures much higher than their equilibrium temperatures due to this effect.
What is the greenhouse effect?
This measurement, calculated from the difference in a star’s magnitude through two filters (e.g., B and V), provides an indication of its temperature and classification.
What is the color index?
This temperature is reached when the energy absorbed by a planet from its star equals the energy it radiates back into space.
What is equilibrium temperature?
Space telescopes like this ESA mission have revolutionized parallax measurements by eliminating atmospheric interference, allowing for precise mapping of over a billion stars.
What is Gaia?
Optical depth depends on the density of the medium, the distance light travels through the medium, and this property.
What is the cross sectional area of the particles in the medium?
Equilibrium temperature estimates must account for this variation in stellar flux experienced by a planet with an eccentric orbit.
What is the orbital distance?
Intrinsic stellar magnitudes are referred to as absolute magnitudes and are defined as a star's brightness when viewed from this standard distance.
What is 10 parsecs?