Astronomers believe that disks of material will form around protostars that are spinning. Which of the following observed phenomena is a good indication of the presence of a disk around a protostar?

Question

Quizplus · Accepted Answer

Jets and Herbig-Haro objects are often seen emanating from disks around protostars, indicating their presence. HII regions are ionized by hot, young stars but do not indicate the presence of a disk. Pillars of dust are a product of star formation but do not necessarily indicate the presence of a disk. The presence of molecules in giant clouds of gas and dust can indicate the potential for star formation, but it does not necessarily indicate the presence of a disk. Gamma rays detected from the direction of giant molecular clouds could be indicative of high-energy processes, but again, does not necessarily indicate the presence of a disk.

Answer: C
 The Hertzsprung-Russell diagram (H-R diagram) is a graph that plots stars based on their temperature and luminosity. By studying the H-R diagram, astronomers can learn about the internal structure and evolution of stars. The answer is not A, as HII regions are ionized by hot, young stars but do not relate to the H-R diagram. The answer is not B, as huge pillars of dust, like those seen by the Hubble in the Eagle Nebula, are a product of star formation but also do not relate directly to the H-R diagram. The answer is not D, as while the presence of molecules in giant clouds of gas and dust can indicate the potential for star formation, it does not relate directly to the H-R diagram. The answer is not E, as gamma rays detected from the direction of giant molecular clouds may be indicative of high-energy processes but are not directly relevant to the H-R diagram.

Astronomers Believe That Disks of Material Will Form Around Protostars