Table of Contents
24 relations: Apparent magnitude, Astronomical spectroscopy, Celestial equator, Constellation, Cyanogen, Effective temperature, Epoch (astronomy), Giant star, Horizontal branch, Hydra (constellation), Light-year, Main sequence, Monthly Notices of the Royal Astronomical Society, Photosphere, Radial velocity, Red clump, Solar luminosity, Solar mass, Solar radius, Star, Stellar classification, Stellar core, Stellar evolution, Triple-alpha process.
Apparent magnitude
Apparent magnitude is a measure of the brightness of a star or other astronomical object.
See 9 Hydrae and Apparent magnitude
Astronomical spectroscopy
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects.
See 9 Hydrae and Astronomical spectroscopy
Celestial equator
The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth.
See 9 Hydrae and Celestial equator
Constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
See 9 Hydrae and Constellation
Cyanogen
Cyanogen is the chemical compound with the formula (CN)2.
Effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation.
See 9 Hydrae and Effective temperature
Epoch (astronomy)
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity.
See 9 Hydrae and Epoch (astronomy)
Giant star
A giant star has a substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature.
Horizontal branch
The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red-giant branch in stars whose masses are similar to the Sun's. 9 Hydrae and horizontal branch are horizontal-branch stars.
See 9 Hydrae and Horizontal branch
Hydra (constellation)
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees, and also the longest at over 100 degrees.
See 9 Hydrae and Hydra (constellation)
Light-year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly 9,460,730,472,580.8 km (Scientific notation: 9.4607304725808 × 1012 km), which is approximately 5.88 trillion mi.
Main sequence
In astronomy, the main sequence is a classification of stars which appear on plots of stellar color versus brightness as a continuous and distinctive band.
See 9 Hydrae and Main sequence
Monthly Notices of the Royal Astronomical Society
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields.
See 9 Hydrae and Monthly Notices of the Royal Astronomical Society
Photosphere
The photosphere is a star's outer shell from which light is radiated.
Radial velocity
The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points.
See 9 Hydrae and Radial velocity
Red clump
The red clump is a clustering of red giants in the Hertzsprung–Russell diagram at around 5,000 K and absolute magnitude (MV) +0.5, slightly hotter than most red-giant-branch stars of the same luminosity.
Solar luminosity
The solar luminosity is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun.
See 9 Hydrae and Solar luminosity
Solar mass
The solar mass is a standard unit of mass in astronomy, equal to approximately.
Solar radius
Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun.
Star
A star is a luminous spheroid of plasma held together by self-gravity.
Stellar classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
See 9 Hydrae and Stellar classification
Stellar core
A stellar core is the extremely hot, dense region at the center of a star.
Stellar evolution
Stellar evolution is the process by which a star changes over the course of its lifetime and how it can lead to the creation of a new star.
See 9 Hydrae and Stellar evolution
Triple-alpha process
The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.
See 9 Hydrae and Triple-alpha process
References
Also known as 9 Hya.