b) When viewed from the earth, a red star and a blue star appear to be
qually bright what could you infer about these two stars?
Answers
Answer:
If you are viewing them with the naked eye you can assume that the red star is at a giant or supergiant stage because no red dwarf is bright enough to be seen with the naked eye, not even Proxima Centauri which is the nearest star to the sun yet discovered. You can also infer that the bluer star has a hotter surface temperature. You cannot infer distance because though a redder star will be cooler, it also has a much greater diameter so may be as luminous as a hotter bluer star. Nor can you infer its mass because a red giant or supergiant may be as massive as its bluer main sequence stage. You can tell if its a variable star because its brightness will change in relationship to the other star. A typical example is Betelgeuse which normally varies from a little brighter than its neighbour Rigel to a little dimmer, only at present it has dimmed so much that it is barely the second brightest star in Orion.
If you are viewing them with the naked eye you can assume that the red star is at a giant or supergiant stage because no red dwarf is bright enough to be seen with the naked eye, not even Proxima Centauri which is the nearest star to the sun yet discovered. You can also infer that the bluer star has a hotter surface temperature. You cannot infer distance because though a redder star will be cooler, it also has a much greater diameter so may be as luminous as a hotter bluer star. Nor can you infer its mass because a red giant or supergiant may be as massive as its bluer main sequence stage. You can tell if its a variable star because its brightness will change in relationship to the other star. A typical example is Betelgeuse which normally varies from a little brighter than its neighbour Rigel to a little dimmer, only at present it has dimmed so much that it is barely the second brightest star in Orion.Of course if you are an astronomer you can use many techniques to determine, distence, radius, mass, luminosity, spectral type, chemical composition, relative motion, whether its a single star, binary or mutiple star, what’s lifecycle stage it is etc
Explanation:
If you are viewing them with the naked eye you can assume that the red star is at a giant or supergiant stage because no red dwarf is bright enough to be seen with the naked eye, not even Proxima Centauri which is the nearest star to the sun yet discovered. You can also infer that the bluer star has a hotter surface temperature. You cannot infer distance because though a redder star will be cooler, it also has a much greater diameter so may be as luminous as a hotter bluer star. Nor can you infer its mass because a red giant or supergiant may be as massive as its bluer main sequence stage. You can tell if its a variable star because its brightness will change in relationship to the other star. A typical example is Betelgeuse which normally varies from a little brighter than its neighbour Rigel to a little dimmer, only at present it has dimmed so much that it is barely the second brightest star in Orion.
Of course if you are an astronomer you can use many techniques to determine, distence, radius, mass, luminosity, spectral type, chemical composition, relative motion, whether its a single star, binary or mutiple star, what’s lifecycle stage it is etc