Exam 9: The Formation and Structure of Stars

How does a gas cloud become hot

If the dust around a protostar radiates most strongly at 30 microns or 30,000 nm, what is the approximate temperature of that dust Hint: T in K = 3,000,000/wavelength in nm or use Wien's Law.

In the following visible + near infrared image, the white color is the ______, the red color is the __________, and the lack of white color (or black color) sandwiched between the upper white half-moon shape and the lower white half-moon shape is _________________.

Emission nebulae are also called ________ because they are composed of ionized hydrogen.

You would use the 21-cm radio emission line to map out ____________.

The image on the right indicates star formation that we cannot see in the wavelength band on the left. The image on the left is a/an __________ wavelength image of the ___________ wavelength image on the right.

The visual wavelength image shown above is an object that is found in and near star-forming regions.

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

T Tauri stars are believed to be young, high-mass main-sequence stars.

-The above reactions are of the ___________________.

How long can a four-solar-mass star live

________ are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin. Other minor fusion reactions do occur in these objects. They fall in a gap between the low-mass M dwarf stars and the massive planets in which nuclear fusion never occurs.

Some massive stars only live a few million years.

What force(s) are responsible for the collapse of an interstellar cloud

Hydrostatic equilibrium refers to the balance between weight and pressure.

in the following image, the forming star is clearly seen.

Why are interstellar absorption lines so narrow compared to the width of lines which originate in the photospheres of stars

Energy flows by radiation or convection inside stars but almost never by conduction.

A ZAMS star is located _______________________.

-The above image is an example of a ________.