What is an appropriate surface temperature of a Class H star?
7,500-10,000K
A note on the spectral atlas and spectral classification
| Spectral Type | Surface Temperature | Distinguishing Features |
|---|---|---|
| A | 7,500-10,000K | H; CaII; HeI and HeII absent |
| F | 6,000-7,500K | H; metals (CaII, Fe, etc) |
| G | 5,000-6,000K | H; metals; some molecular species |
| K | 3,500-5,000K | metals; some molecular species |
What is the hottest star in Class A?
A0
The spectral classes O through M are subdivided by Arabic numerals (0–9). For example, A0 denotes the hottest stars in the A class and A9 denotes the coolest ones.
What happens when stars burn hydrogen?
The hydrogen burning in the shell heats the surrounding mass of the star and causes it to expand. The radius of the star increases and the surface temperature drops. The luminosity of the star increases dramatically, and it becomes a red giant.
Are class O stars the hottest?
The spectral sequence of stars runs OBAFGKM. O stars are the hottest, with temperatures from about 20,000K up to more than 100,000K. These stars have few absorption lines, generally due to helium. These stars burn out in a few million years.
Why do O class stars show weaker hydrogen lines than B class stars?
The spectra of O-Type stars shows the presence of hydrogen and helium. At these temperatures most of the hydrogen is ionized, so the hydrogen lines are weak.
What temperature does hydrogen burn at?
Flame Temperatures
| Fuel | Flame Temperature |
|---|---|
| cigarette | 400-700 °C (750-1,300 °F, air) |
| ethane | 1,960 °C (air) |
| hydrogen | 2,660 °C (oxygen), 2,045 °C (air) |
| MAPP | 2,980 °C (oxygen) |
Do all stars burn hydrogen?
All stars begin fusing hydrogen into helium, but what comes next is temperature-dependent. In particular: If your star is too low in mass, it will fuse hydrogen into helium only, and will never get hot enough to fuse helium into carbon.
Which is the rarest star?
An O-type star is a hot, blue-white star of spectral type O in the Yerkes classification system employed by astronomers. They have temperatures in excess of 30,000 kelvin (K).
What is the rarest star type?
O-type star
Each is classified as an O-type star — and O-type stars are the rarest main sequence stars in the universe, comprising just 0.00003% of known stars. They’re extremely prone to going supernova and collapsing into black holes or neutron stars.