Search
Menu
DataRay Inc. - ISO 11146-Compliant Laser Beam Profilers
Photonics Dictionary

luminosity

Luminosity refers to the total amount of energy emitted by an astronomical object, typically measured per unit time. It quantifies the intrinsic brightness of the object and is often expressed in terms of power (energy per unit time), such as watts or solar luminosities.

In astronomy, luminosity is a fundamental property used to characterize stars, galaxies, and other celestial objects. For stars, luminosity is a measure of the total amount of energy radiated by the star each second across all wavelengths. It is determined by factors such as the star's surface temperature, size (radius), and distance from Earth.

Luminosity is often compared to apparent brightness, which is how bright an object appears from a specific vantage point, such as Earth. Apparent brightness depends not only on the intrinsic luminosity of the object but also on its distance from the observer and any intervening material that might absorb or scatter light.

The concept of luminosity is crucial for understanding the properties and evolution of astronomical objects. For example, the Hertzsprung-Russell (H-R) diagram, a fundamental tool in stellar astrophysics, plots stars' luminosities against their surface temperatures (or spectral types), revealing patterns and relationships that provide insights into stellar evolution, classification, and behavior.

Luminosity is also used to classify galaxies based on their total output of energy and to study the evolution of the universe on cosmic scales. In cosmology, the luminosity of distant supernovae is used as a standard candle to measure cosmic distances and study the expansion rate of the universe.
 

Explore Our Content
News
Features
Latest Products
Webinars
White Papers
All Things Photonics Podcast
Photonics Spectra Now
Videos
Our Summits & Conferences
Industry Events
Bookstore
Join Our Community
Subscribe
Advertise
Become a member
Sign in
Contribute a Feature
Suggest a Webinar
Submit a Press Release
Mobile Apps

About Us
Our Company
Our Publications
Contact Us
Career Opportunities
Teddi C. Laurin Scholarship

Terms & Conditions
Privacy Policy
California Consumer Privacy Act (CCPA)



©2024 Photonics Media
100 West St.
Pittsfield, MA, 01201 USA
[email protected]
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.