Star with Unexpected Color Discovered / First Green Star Found

Astronomers have identified a type of white dwarf that, based on spectral calculations, could appear greenish-yellow when observed from a close distance. The celestial object is known as WD J1330+6435, and the new finding shows that the apparent color of white dwarfs is not always white or blue, contrary to common belief.

Astronomers have identified a type of white dwarf, which, based on calculations of its light spectrum, can be seen in a yellowish-green color when viewed from a close distance. This object is known as WD J1330+6435 and the new finding shows that the appearance color of white dwarfs is not always white or blue, contrary to popular belief.

According to Ambassador Arjan, researchers have examined the color of 151 white dwarfs at a maximum distance of 65 light years from Earth. The results showed that most of these objects have a color close to white, but a few of them show unusual colors.

Scientists have studied the light spectrum of a white dwarf and, using models related to human vision, predict that it will appear green at close range.

A white dwarf is the hot, compact core of a star that has completed its prime phase of life. Stars like the Sun, after using up their nuclear fuel, first become red giants and then lose their outer layers. The remaining core eventually becomes a white dwarf.

These objects contain a lot of mass in a very small volume. They no longer derive their energy from sustained nuclear fusion, but gradually lose residual heat from earlier stages of the star's life.

The color of many stars mainly depends on their surface temperature, but in white dwarfs, the chemical composition of the atmosphere can also play an important role in determining the color.

The white dwarf WD J1330+6435 has trace amounts of heavy elements in its atmosphere, including sodium, calcium and lithium. These materials may have entered the star's atmosphere as a result of the debris of planetary bodies falling to the surface of the star.

Atoms of these elements absorb specific wavelengths of light. In this celestial body, absorption of parts of yellow, orange and red light by sodium and absorption of part of violet and blue light by calcium changes the output light spectrum. As a result, the relative contribution of the remaining wavelengths increases, and calculations show that the apparent color of the star is close to yellow-green, known as "light olive".

This white dwarf is not the only interesting example of this research. Some white dwarfs may appear pink. A phenomenon that can be related to the presence of carbon molecules in their outer layers. Other examples are also seen in yellow, turquoise or blue. In these cases, the temperature and the chemical composition of the atmosphere both play a role in the formation of color.

These results have been published in the scientific journal RAS Techniques and Instruments. The importance of research is not only in finding an object with an unusual color; Rather, it shows that the chemical composition of the atmospheres of stars can change our visual experience of them in ways that cannot be predicted by surface temperature alone.