Question

1. which of the following characteristics is not used to classify stars?

year of origin
size
brightness
temperature

Explanation:

Stars are classified based on characteristics like size (e.g., dwarf, giant), brightness (apparent and absolute magnitude), and temperature (related to spectral class). However, the year of origin is not a factor in star classification as stars form over vast cosmic timescales and their classification focuses on observable physical properties rather than a specific year of formation.

Answer:

year of origin