The mass unit used for the invisible partner in the estimate is which?

The mass unit used for the invisible partner in the estimate is which?

• A. Solar masses
• B. Earth masses
• C. Jupiter masses
• D. Kilograms

Answer: (A)

Masses of stars and compact objects are usually expressed in solar masses because it directly compares to the Sun’s mass and keeps numbers meaningful for stellar-scale objects. When you estimate an invisible companion’s mass from orbital motions, using solar masses lets you immediately see whether it’s a normal star, a white dwarf, a neutron star, or a black hole. Earth or Jupiter masses are handy for planets or very small bodies, and kilograms would yield unwieldy, hard-to-interpret numbers for such massive objects. So the standard unit used for the invisible partner in this estimate is solar masses.

Masses of stars and compact objects are usually expressed in solar masses because it directly compares to the Sun’s mass and keeps numbers meaningful for stellar-scale objects. When you estimate an invisible companion’s mass from orbital motions, using solar masses lets you immediately see whether it’s a normal star, a white dwarf, a neutron star, or a black hole. Earth or Jupiter masses are handy for planets or very small bodies, and kilograms would yield unwieldy, hard-to-interpret numbers for such massive objects. So the standard unit used for the invisible partner in this estimate is solar masses.