USAAAO 2026, I кръг — Задача 20

USAAAO 2026 - First Round · 9 февруари 2026 г.

Problem writers

Problem writers: Srihari (Hari) Balaji, Vincent Bian, Ferdinand, Hagan Hensley, Elizabeth Lee, Joe McCarty, Lucas Pinheiro, Feodor Yevtushenko

Условие

Some stars formed in the early universe are still observable today. If an observer observed one and it is still in the main sequence phase, what would most likely be its mass?

(a) <2 M⊙< 2\ \mathrm{M_{\odot}}

(b) 2−8 M⊙2 - 8\ \mathrm{M_{\odot}}

(c) 8−12 M⊙8 - 12\ \mathrm{M_{\odot}}

(d) 12−20 M⊙12 - 20\ \mathrm{M_{\odot}}

(e) >20 M⊙> 20\ \mathrm{M_{\odot}}

Отговори

Решение

Оригинал в Архива: usaaao_first_exam_2026.pdf · официални решения: usaaao_first_exam_solutions_2026.pdf