What is the coolest star stellar class?

The spectral sequence is also a colour sequence: the O- and B-type stars are intrinsically the bluest and hottest; the M-, R-, N-, and S-type stars are the reddest and coolest.

What type of star main sequence giant or is Betelgeuse?

Classified as a red supergiant of spectral type M1-2, Betelgeuse is one of the largest stars visible to the naked eye.

How is a Subgiant star formed?

Subgiant phase When a star exhausts the hydrogen in its core, it leaves the main sequence and begins to fuse hydrogen in a shell outside the core. The core increases in mass as the shell produces more helium.

What color are Subgiant stars?

redder
Subgiants are stars that are redder and larger than main-sequence stars of the same luminosity.

Is Betelgeuse hotter than Sun?

Betelgeuse is actually cooler than our sun. The sun’s surface temperature is about 5,800° Kelvin (about 10,000° Fahrenheit), and Betelgeuse is roughly half that, about 3,000° Kelvin (about 5,000° Fahrenheit). That is why it is red — red stars are cooler than the sun, blue-white stars are hotter.

What class are the hottest stars?

Spectral Classification of Stars

• O stars are the hottest, with temperatures from about 20,000K up to more than 100,000K.
• B stars have temperatures between about 10,000 and 20,000K.
• A stars have strong absorption lines of Hydrogen.
• F stars are slightly hotter than the Sun.

Is Betelgeuse a main sequence star?

Betelgeuse is a red supergiant star in the constellation Orion. It left the main sequence about one million years ago and has been a red supergiant for about 40,000 years. It’s known as a semi-regular variable star, which means its brightness is variable.

Is our Sun considered a Subgiant star?

A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars….Properties.

Which Roman numeral in the diagram refers to a Subgiant?

The spectral types are shown at the coolest temperature for each type. A Roman numeral V designates the main sequence stars, subgiants by IV, giants by III, bright giants by II and supergiants by Ia and Ib.

How large is a Subgiant star?

0.4 M ☉ to 0.9 M ☉

Which star is brighter Antares or Betelgeuse?

Both stars are typical massive M2 supergiant stars, 500-600 light years away. Betelgeuse is slightly brighter (V = 0.45), perhaps because it is slightly more luminous. This means that, if Antares was where the sun is, we would be well inside it! Red Antares A has a hot blue companion Antares B, a B2.

What kind of star is the Betelgeuse star?

Betelgeuse is a semiregular variable star, classified in the subgroup SRc, which also includes Mu Cephei (Herschel’s Garnet Star), RW Cygni, VX Sagittarii, and CE Tauri.

What kind of planets would Betelgeuse engulf?

Betelgeuse would engulf all four terrestrial planets — Mercury, Venus, Earth and Mars — and even the gas giant Jupiter. Only Saturn would be beyond its surface. Credit: The star’s precise diameter has been difficult to measure because Betelgeuse is a pulsating variable and its radius keeps changing.

Which is brighter a giant star or a subgiant star?

A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as true giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of a star.

Which is brighter Achernar or Betelgeuse in infrared?

Most of the time, it is only slightly fainter than Achernar (Alpha Eridani) in the constellation Eridanus and slightly brighter than the Southern Pointer Hadar (Beta Centauri) in Centaurus. In infrared wavelengths, Betelgeuse is brighter than any other star in the sky.