If astronomers discovered a G2 star similer to the sun except it showed little rotation. how would it similar?

Answer 1

Well, the Sun itself is not a 'rapid rotator' (26-days or so).

What distinguishes a "Main Sequence" star from another is its mass.

Stars with the same mass will be of the same size (therrefore, same density) and, generally, have the same central temperature and pressure = same rate of energy production = same energy output = same flux (energy per square metre of surface area) = same distribution of energy along the spectrum (same number of Watts per slice of frequency) = same color = same spectrum = same classification (e.g., G2).

The only things that can cause differences are:

1) rapid rotation: it has to be fast enough so that the surface speed at the equator approaches the escape velocity. This reduces the pressure along the equatorial plane and makes that region appear cooler (as if the star was less massive than it really is).

You could have a star more massive than the Sun, but rotating very rapidly, appear as a G2 (instead of a hotter late F, for example); but we'd be able to tell the difference.

You could have a star less massive than the Sun (therefore should appear cooler) but with no rotation at all. In theory, its surface will not be as 'lifted' by rotation as the Sun's and it could appear as a G2 when it should be, let us say a G3. But the Sun's rotation is so slow that very likely the difference would not be that much.

2) the amount of "metal". In astronomy, anything other than hydrogen and helium is called metal. The original stars that were created early in the universe were only hydrogen and helium. As the bigger ones exploded, they gave their "ashes" (the metals created by fusion and by the explosion) back to the universe.

Stars that were created later (like our Sun) contain "metals". This affects the rate of nuclear fusion at the core (and, in a less important way, the way the heat is conducted to the surface).

So, it is possible that an earlier generation star (less "metals") appears as a G2 even though it has a slightly different mass than our sun. Same goes for stars that have more metal than our Sun.

3) Off the Main sequence. Once a star runs out of fuel, it runs off the main sequence. If it is massive enough, it blows up, leaving its core as a neutron star or a black hole.

Less massive stars (there are far more of them) simply become white dwarfs, shining by the heat accumulated in their now exposed cores.

For example, Sirius B (the small companion to Sirius) is over 25,000 K. As it cools over the next billions of years, it will reach a temperature of 6,000 K one day. It will then appear (at least in temperature-color) as a G2 star. But it is much smaller than our Sun, and its density is much much greater than that of our Sun.

There are plenty of white dwarfs out there...

Answer 2

it would be similar in temperature, color, and mass. hope this helps!!!!!