Orange Star (K-Type Star)

Orange Stars are also known as K-Class type stars, which are slightly cooler than our star. Orange dwarf stars are also smaller than our Sun. These orange (dwarf) stars last longer than our Sun. Whilst our star will live for ten billion years, of which it is middle-aged, an Orange Star could live for between 15 and 45 billion years. N.A.S.A.

As orange stars are much cooler than yellow dwarves, any planets that could support life would be located nearer to the star than for larger stars. An Orange star would have a rough temperature of between 3,900 and 5,200. To put that in context, the Suns' surface temperature is about 5,778 K.

Orange Stars typically have between 50 - 80% of the mass of the Sun. They are calm stars compared to Red Dwarfs and are not prone to unleashing flares on planets that might be orbiting. New Scientist

Giant Orange Stars

The following two giant stars s are known to have planets in orbit around them. Both are the Alpha stars of their respective constellations, and both are Zodiac constellations. They double-figure times larger than our Sun.

An Orange Giant Star example is Hamal, which is the brightest star in the constellation of Aries. Hamal has the Bayer reference Alpha Arietis to signify this. The star is roughly 11 times the size of the Sun.

Another star that is an Orange Giant is Aldebaran which is the brightest star in the constellation of Taurus. Aldebaran is designated the brightest by being given the Bayer reference Alpha Tauri. It is estimated to be over 30 times the size of the Sun.

Exoplanets

Whilst orange Dwarf Stars are not as common as Red Dwarf Stars, they are more abundant than Yellow Dwarf Stars. There is a greater range of stars to be searched. Orange Dwarf Stars are less likely to flame, their planets being more stable, but they don't live as long. Any planet orbiting an Orange Dwarf would have had time to evolve; these are stars of interest for planet finders.

Orange Dwarf Stars are thought of as being the best place to look for alien life. The stars are believed to be stable, and therefore, life would be able to get a foothold on the planets. As orange stars are smaller and colder than yellow stars, the planets need to orbit closer to the star than a star orbiting a yellow star would need to be.

Stable, meaning that the planets would not be flamed by their stars. When Proxima Centauri, the nearest star to the Sun, had an exoplanet, hope for life turned to disappointment when it was revealed that Proxima flamed its planet, cleansing the planet of life.

Hamal (Alpha Arietis)

Hamal (Alpha Arietis) is a large K-class star, an orange star that has been identified as having a planet orbiting it. Hamal is a gas giant and, therefore, is not suitable for life like that on Earth. Hamal is more massive than Jupiter (1.8 x J Mass, 1.2 x J Radius). If the planet were rocky, it still wouldn't be able to support life as it is too hot.

There's a mistake on the page. It says Hamal can't be seen on Earth, but there's no contact information to challenge that. Hamal is a 2.01 magnitude star that can be seen from Earth. Anything below 6.5 Mag is visible to the naked eye. N.A.S.A. .

Ran (Sadira)

A notable orange dwarf is Sadira or Ran, as it is officially now known, in the constellation of Eridanus. At least two exoplanets have been detected orbiting around Ran as they are older and live longer than most other stars, such as our own. Intelligent alien life forms could have built up a complex civilisation. Therefore, these are of great interest to those searching for extra-terrestrial life forms. We have not yet received any signals from there. Ran is about ten light-years from us, a neighbour.

Example Orange Dwarf Stars

• Wasp-2 in the constellation of Delphinus
• Ran (Sadira) in the constellation of Eridanus
• AB Pictoris in the constellation of Pictor

Orange Star Fact Summary

• Regarding temperatures, Orange Stars are mid-way between Yellow and Red stars.
• They have been 50 - 80% the mass of the Sun but can still be bigger than the size of the Sun.
• Orange Stars are cooler than the Sun, and so the Goldilocks Zone, the area around a star whose planets can support life is closer to that what they would be for a star like the Sun.
• They are stable stars, less likely to flare their stars and sanitise the planets of life forms, so scientists study these types of stars.
• They are more fuel efficient than the Sun and will last longer.
• Notable Orange Star is Hamal in the constellation of Aries the Ram.

Last Modified : October 2024