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Two nearby small irregular galaxies about 160,000 light years, and 200,000 light years distant, visible to the naked eye from the Southern Hemisphere
Magellanic Clouds LMC & SMC
A well-defined band on an H-R diagram
on which most ✮✮✮ tend to be found
, running from the top left
of the diagram to the
The point where ✮✮✮ are just beginning to evolve off is the main-sequence turnoff on an H-R diagram for a cluster. If all the ✮✮✮ in a particular cluster are plotted, the lower mass ✮✮✮ will trace out the main sequence up to the point where ✮✮✮ begin to evolve off the main sequence toward the red giant branch.
A measure of the total amount of matter contained within an object.
The dependence of the luminosity of a main-sequence ✮ on its mass. The luminosity increases roughly as the mass is raised to the third power.
The dependence of the radius of a main-sequence star on its mass. The radius rises roughly in proportion to the mass.
The specific galaxy to which the Sun belongs, so named because most of its visible ✮✮✮ appear overhead on a clear, dark night as a milky band of light extending across the sky
Milky Way Galaxy
The lowest point
on any temperature scale; the temp at which all (non-quantum mechanical) motion ceases:
A _____ galaxy is one which shows explosive activity and can emit large amounts of energy, especially from its central regions.
A system in which ✮✮ orbit about their common center of gravity like Sirius A & B
- binary star system
- Sirius A (upper right) & Sirius B (lower left)More Info:
Also referred to as the Planck curve
The way in which the intensity of radiation emitted by a hot object in thermal equilibrium depends on F. The F at which the emitted intensity is is an indication of the temp of the radiating object.
Large, hot, bright ✮
at the upper left end
of the main sequence
on the H-R diagram
. Its name comes from its color
Clouds of collapsing gas and dust that did not contain enough mass to initiate core
☢ fusion. Because of their small size & low temp, they are extremely difficult to detect.
an evolved ✮
that has exhausted the hydrogen fuel in its ☢
powered by ☢ reactions in a hot shell around the stellar core.
the diameter of a _____ is much larger than that of the ☼
relatively low surface temp
red giant star
An extremely luminous and large red ✮
Celestial coordinate used to measure longitude on the celestial sphere. The zero point is the position of the Sun on the vernal equinox.
Pair of quantities - right ascension & declination - similar to longitude and latitude on Earth, used to pinpoint locations of objects on the celestial sphere.
Celestial coordinate system used to measure latitude above or below the celestial equator on the celestial sphere
Imaginary sphere surrounding the Earth, to which all objects in the sky were once considered to be attached.
The projection of the Earth's equator onto the celestial sphere.
- celestial sphere
- celestial equator
A grouping of stars in the night sky in a recognizable pattern.
Most of the constellations get their name from the Latin translation of one of the ancient Greek star patterns that lies within it. In more recent times, a number of additional groups were introduced by modern astronomers
There are now __ standard configurations recognized.
Any ✮ with a radius comparable to, or smaller than that of the Sun (including the Sun itself).
The entire range of electromagnetic waves
, named in order of increasing frequency or energy, ranges from
visible [or optical] (what the eye sees)
electromagnetic spectrum or EM spectrum