Question

The characteristic absorption spectra of two stars are shown. Indicated in each is a set of absorption lines due to interstellar material between us and the stars. Using this information and the spectral drawings shown below complete parts a - e of this question.

Interstellar Absorption Lines Spectra of star A Spectra of star B

a. The interstellar absorption lines appear more intense in the spectrum of star A than star B. What does this mean in terms of the number of absorbing atoms between the earth observer's line of sight to star B compared to star A?

b. If we assume that the interstellar material is uniformly distributed along the direction to each of these stars, which star is probably farther away? Explain.

c. If these two stars are at the same distance, explain why the interstellar lines are more intense in spectra A compared to spectra B.

d. How can it proved that some absorption lines in the spectra of some stars are due to interstellar material?

e. Since scattering by dust leaves the colors of stars reddened, we can recognize the existence of interstellar material in the direction of any particular star by comparing its color to what we expect for its particular spectral class. Describe how the amount of "reddening" may depend on the distance to the star and/or the amount of material between us and the star.

Answer 1

A pressure system is a relative peak or lull in the sea level pressure distribution. The surface pressure at sea level varies minimally, with the lowest value measured 87 kilopascals (26 inHg) and the highest recorded 108.57 kilopascals (32.06 inHg). High- and low-pressure systems evolve due to interactions of temperature differentials in the atmosphere, temperature differences between the atmosphere and water within oceans and lakes, the influence of upper-level disturbances,^[jargon] as well as the amount of solar heating or radiationized cooling an area receives. Pressure systems cause weather to be experienced locally. Low-pressure systems are associated with clouds and precipitationthat minimize temperature changes throughout the day, whereas high-pressure systems normally associate with dry weather and mostly clear skies with larger diurnal temperature changes due to greater radiation at night and greater sunshine during the day. Pressure systems are analyzed by those in the field of meteorology within surface weather maps.