Final answer:
Yes, we can learn a star's composition by analyzing its spectrum. Stars are mostly composed of hydrogen and helium. Characteristics such as a star's temperature, composition, and pressure can be determined by the spectrum, which has been immensely aided by contributions like those from Annie Cannon in classifying stellar spectra.
Step-by-step explanation:
1) The answer to the student's question is true. We can determine a star's composition by looking at its spectrum. When it comes to understanding if a star is actually red or if its light has been reddened by interstellar dust, we would need to analyze the starlight in more detail.
2) Color is a measure of a star's temperature because a star emits thermal radiation, and the peak wavelength at which a star emits light is determined by its surface temperature, following Wien's displacement law.
3) The main reason that the spectra of all stars are not identical is that each star has its own unique composition and conditions, such as temperature and pressure, which affect the absorption and emission lines in their spectra.
4) Stars are mostly made of hydrogen and helium, and this is known through the study of stellar spectra, where specific absorption and emission lines correlate to the presence of these elements.
5) Annie Cannon made significant contributions to the classification of stellar spectra, which is key to understanding the temperature, luminosity, and composition of stars.
6) Five characteristics of a star that can be determined by measuring its spectrum include temperature, composition, luminosity, size, and pressure differences within the star's atmosphere. The spectrum is used by matching observed lines with known spectral lines from various elements and by noting the width and intensity of these lines, which give clues about the star's physical properties.
7) Objects of spectral types L, T, and Y differ from those of the other spectral types mainly in their temperature ranges, where they are cooler and emit most of their radiation at infrared wavelengths.
8) Stars that look brighter in the sky have smaller magnitudes than fainter stars. The magnitude scale is inversely proportional to brightness.
9) Antares with an apparent magnitude of 1.0 is less bright than Procyon with an apparent magnitude of 0.4 as a smaller magnitude number indicates brighter appearance in the sky.