If the Milky Way Formed Stars at Approximately a Constant

question 83

Multiple Choice

If the Milky Way formed stars at approximately a constant rate over the last 14 billion years,what fraction of the M-type stars that ever formed in it can still be found as main-sequence stars today? Note that M-type stars have a mass of approximately 0.5 M_⨀.

• A)10 percent
• B)33 percent
• C)50 percent
• D)75 percent
• E)100 percent

---

Definitions:

Hydrogen Bonded

Describes a type of chemical bond that occurs when a hydrogen atom, which is covalently bonded to a highly electronegative atom, forms an electrostatic or partial covalent bond with another electronegative atom.

Tertiary Amides

Amides derived from carboxylic acids where the nitrogen atom is bonded to three other carbon atoms, not including the carbonyl carbon.

Secondary Amides

Organic compounds characterized by a carbonyl group (C=O) attached to a nitrogen atom, which in turn is bonded to two alkyl or aryl groups.

Acid Chlorides

Reactive derivatives of carboxylic acids where the hydroxyl group is replaced with a chlorine atom, used in organic synthesis.