- A star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated 1022 to 1024 stars. Only about 4,000 of these stars are visible to the naked eye—all within the Milky Way galaxy.
- Gamma Trianguli Australis (stars.astro.illinois.edu)
GAMMA TRA (Gamma Trianguli Australis). If this star were not so bright – within the top 150 stars – it would probably be ignored. But at mid-third magnitude (2.89), it just barely makes the list at number 149, and thus earns some measure of respect, which it deserves if for no other reason than that it anchors the southwest apex of bright and obvious Triangulum Australe (the Southern Triangle), which is dominated by mid-second magnitude Atria.