Color in Astronomy

Color is essential to telling planets’ and stars’ stories. By measuring the exact color of celestial bodies, scientists can learn about the age, chemical composition and temperature of these forms without traveling hundreds of thousands of miles. Spectrophotometers allow scientists to accurately and objectively measure the color of astronomical bodies no matter their distance, so we can learn more about the galaxy we inhabit. 

What Colors Are in Space? 

Space has a great spectrum of colors regarding celestial bodies, and celestial bodies are typically assorted into a spectral class according to their hue. Celestial bodies go through phases of spectral evolution where they behave similarly to iron heated in a fire. Throughout their evolutionary phases, they will shift from red to orange, yellow, white, or blue as they reach their hottest phases. Depending on trace amounts of elements — aside from hydrogen and helium — stars may appear in cooler secondary colors like purple and green. 

Stars can exhibit the following colors, in order from hottest to coldest: 

  • O: Blue
  • B: Blue/White
  • A: White
  • F: White/Yellow
  • G: Yellow
  • K: Orange
  • M: Orange/Red

Around 88% of all stars in our universe are of the K and M variety, while G stars like the sun make up only 8% of celestial bodies. But while most of the universe may be orange and red, it’s also home to impressive blues, greens, purples, reds and whites. 

What Is Astronomical Spectroscopy?

Astronomical spectroscopy refers to the practice of determining the properties of stars by measuring their electromagnetic wavelengths. By closely examining the electromagnetic wavelengths of celestial bodies, scientists can study the percentage of helium, hydrogen and trace elements in a star, plus its age and spectral evolution phase. Astronomical spectroscopy often uses Planck’s curve to determine a star’s peak wavelength from hundreds of thousands of miles away. 

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How Do Astronomers Use Spectroscopy?

Spectroscopy was first used for astronomical purposes by William Wollaston in 1802. Wollaston used spectroscopy to analyze the sun’s electromagnetic spectrum. Later scientists would discover that the dark lines in the sun’s readings could be produced in a spectrum by passing their light through transparent substances. 

Today, a similar method is used to examine three types of astronomical electromagnetic spectrums, including the continuous, absorption and emission spectrums. The continuous spectrum shows astronomers the presence of ROYGBIV colors, while the absorption and emission spectrums show patterns of dark and bright lines. Together, these three spectrums produce a continuous scope where all wavelengths are present.

Use HunterLab Spectrophotometers for Astronomical Spectroscopy

At HunterLab, we’ve been passionately seeking innovation and truth for the better half of a century. We’ve spent our history quantifying the previously thought unquantifiable and creating spectrophotometers that turned color from a subjective to an objective field of study. HunterLab instruments bring you closer to understanding the beautiful and complex truths of the stars. 

Contact us today to learn more about our astronomical spectrometers and how else we can assist you in finding the right products.