Question 18 (1 point)

spectral lines allow us to directly determine what property of a distant star?

question 18 options:

a)

surface temperature

b)

mass

c)

average density

d)

chemical composition of its outer regions

d) Chemical composition of its outer regions

Explanation:

Spectroscopy is the study of spectral lines, it's an important part of studying the chemistry that goes on in stars and interstellar clouds, spectral lines can give relevant information because every atom or molecule gives off light at a specific frequency, thus, astronomers can look for gas containing a particular atom or molecule by tuning the telescope to one of the gas's characteristic frequencies. Therefore, we can know the chemical composition or a star's outer regions analyzing the spectral lines.

Even though the spectral shape of a blackbody continuum depends on the temperature of the object an there's a relationship between an object’s temperature and the peak of its spectrum, we don't consider this answer as correct because we are not measuring spectral lines but the continuum.

I hope you find this information useful and interesting! Good luck!

b.

developed countries have tended to improve the environment, while developing countries have tended to damage it.

these include the fossil fuels, oil, natural gas, and coal and nuclear energy. hope this ! ^.^

-ella