ViewSpace | Analyzing Light: Spectrum of the Star Altair

Introduction

• Altair is a prominent star found in the constellation Aquila.
• Located in the northern hemisphere, visible in the summer night sky.

Altair Characteristics

• Brightness: 10 times that of the Sun.
• Rotation: Completes an axis rotation every 9 hours.
• Surface Temperature: Approximately 8,000°C.
• Shape: Slightly flattened due to rapid rotation.

Analyzing Starlight

• Methods: Using images and spectra.
  • Images: Capture brightness, color, apparent size, and shape.
  • Spectra: Reveal individual colors and their brightness, providing details about the star's composition, temperature, and motion.

Interactive Overview

• Slider Stops: Six labeled stops showing different views.
  1. Naked-Eye View: Shows Altair in the night sky.
  2. Telescope View: Zoomed view showing Altair's blueish-white color.
  3. Spectrograph: Spreads Altair’s light into a spectrum.
  4. Spectrum: Details the rainbow of Altair’s light.
  5. Graph: Displays brightness of each color.
  6. Interpretation: Explains features on the graph.

Understanding the Spectrum

• Spectrograph: Spreads light into a spectrum.
• Spectrum Details: Shows blueish-white light as a mixture of colors.
• Graph Interpretation: Provides specific brightness of each color.
  • Peak Brightness: Indicates bright colors.
  • Valleys: Indicate dim colors, help deduce composition (e.g., hydrogen presence).
• Graph Labels:
  • Temperature Indicator: Blue peak labeled 8,000°C surface.
  • Rotation Indicator: Green area labeled rotating rapidly.
  • Composition Indicator: Orange valley labeled mostly hydrogen.

Additional Information

• Distance from Earth: 17 light-years.
• Size: 1.8 times the mass and 1.6 to 2 times the radius of the Sun.
• Location: Milky Way.
• Fun Fact: Altair rotates rapidly, causing it to bulge.

Additional Resources

• NASA’s Universe of Learning: Educates on how spectra reveal universe mysteries.
• AstroPix: Explains light analysis to uncover universe mysteries.

Credits

• Data from the UVES Paranal Observatory Project.
• Produced by the Space Telescope Science Institute’s Office of Public Outreach.

Disclaimer

• Content is based on NASA-supported work. Opinions expressed do not necessarily reflect NASA views.