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Chapter 18: Problem 12

Compare and contrast Barnard objects and Bok globules. How many Sun-sized stars could you make out of a Barnard object? Out of a Bok globule?

Short Answer

Expert verified
Barnard objects and Bok globules are both interstellar clouds where star formation can occur, with the former having a much larger mass and size. With reference to the masses used in this solution, a typical Barnard object could create around 30,000 Sun-sized stars, whereas a typical Bok globule could create roughly 50 Sun-sized stars.

Step by step solution

01

Understanding Barnard Objects and Bok Globules

Barnard Objects are dark nebulae, dense regions of interstellar dust and gas where stars can form. They are named after American astronomer E. E. Barnard. They possess a lot of mass – for example, tens of thousands that of the Sun. On the other hand, Bok globules are smaller dark nebulae. They are dense dust and gas clouds found in H II regions, and are so dense that interior regions block light from background stars. They are named after astronomer Bart Bok, who proposed their existence. They possess a much smaller amount of mass – typically about 2 to 50 times that of the Sun.
02

Estimating the Number of Sun-sized Stars

In order to estimate the number of Sun-sized stars that can form from either a Barnard object or a Bok globule, we need to understand the mass of each object and the mass of the Sun. The mass of a Sun-sized star is, by definition, one solar mass. We know that the mass of a Barnard object is typically tens of thousands of solar masses and the mass of a Bok globule is typically 2 to 50 solar masses. Using this information, we can simply divide the mass of each by the mass of the Sun to get an estimate of the number of Sun-sized stars each could produce.
03

Mathematical Calculations

Let's assume a typical Barnard object has a mass 30,000 times greater than that of the Sun. Dividing 30,000 by 1 (the mass of a Sun-sized star), we get 30,000 Sun-sized stars. Similarly, let's take a Bok globule with a mass 50 times that of the Sun. Again, dividing 50 by 1 gives us 50 Sun sized stars.

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Most popular questions from this chapter

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