Distances
The distance to a star that has a parallax angle of 1 arc-second (1")
What is a PAR-SEC?
One of the earliest methods to categorize stars was by measuring the size of this absorption line of hydrogen, leading to the list of stars: A B F G K M O
What is ALPHA?
Our Sun is a star of this category
What is G? (G2V)
The peak wavelength of a star's spectrum is an indicator of this
What is TEMPERATURE?
When you look at light through a diffraction grating, then rainbow you see is called this
What is the SPECTRUM?
The average distance between the Sun and Earth.
What is an ASTRONOMICAL UNIT (A.U.) ?
What is "Oh be a fine girl/guy kiss me" (OBAFGKM)
This part of the Sun is only visible during a solar eclipse, and is mysteriously much hotter than the surface of the Sun
What is the CORONA?
The composition of a star's atmosphere can be determined by looking at ________ lines
What is SPECTRAL?
Balmer lines are visible spectral lines caused by transitions of electrons between the n=2 energy level and higher energy levels in this element
What is HYDROGEN?
The distance that light travels in one year
What is a LIGHT YEAR?
According to Wien's law, stars with a smaller peak wavelength of radiation have a ________ temperature.
What is HIGHER or HOTTER?
What is a SUNSPOT?
The width of spectral lines is a clue to a star's diameter. A large star, such as a supergiant, will have ________ lines, while a smaller star will have _______ lines.
What is NARROW, WIDE?
When a star is moving away from Earth, its spectrum will be ________________.
What is REDSHIFTED?
3.26
What is the number of light-years in a parsec?
The famous chart that plots star Luminosity vs Temperature, leading to the "main-sequence" of stars.
What is the HERTZSPRUNG-RUSSELL (HR) diagram?
What is a CORONAL MASS EJECTION?
This refers to the motion of a star toward or away from Earth, and can be measured with Doppler shifts
What is RADIAL MOTION (or radial velocity)?
When a star is moving toward the Earth its spectrum is __________________.
What is BLUESHIFTED?
A star has a parallax angle of 0.25". This is its distance from the Earth in parsec.
What is 4 par sec?
Among the main-sequence star classes (OBAFGKM), this type of star is the least common
What is O?
The part of the Sun (or any active star) where nuclear fusion takes place, producing the light that we see.
What is the CORE?
This refers to the motion of a star across the sky (transverse)
What is PROPER MOTION?
If we look at a star and one side is redshifted while the other side is blueshifted, we know that the star is doing this
What is ROTATING?