Who they are
Meghnad Saha applied atomic ionisation theory to problems in the solar and stellar atmosphere. His 1920 paper considers how atoms and their ions contribute to observed spectral lines. That theoretical foundation is relevant to Cecilia Payne’s later analysis of stellar atmospheres and the relationship between spectra, physical conditions and inferred composition.
He is an acknowledged theoretical predecessor in the Payne milestone.
Selected contributions
- Authored a 1920 paper applying ionisation physics to the solar chromosphere.Source ↗
- Provided ionisation-theory foundations used in the stellar-atmosphere work discussed by the timeline.Source ↗Source 2 ↗
Selected works
Academic paper · 1920
Ionisation in the Solar Chromosphere
Applies atomic ionisation arguments to the solar atmosphere, beginning with the behavior of calcium and related spectral lines. This is a primary entry point to the ionisation physics later used in stellar-atmosphere analysis.
Linked scan comes from the 1969 Collected Scientific Papers; the original article is Philosophical Magazine, series VI, volume 40, starting p. 472.
Reading scope & citation
First scan page visually read; 1920 Philosophical Magazine metadata checked in the Saha Institute catalogue. Remaining derivation not audited.
In the timeline
Biography sources & portrait credit
- Stellar Atmospheres: A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars ↗Harvard Observatory; Project Gutenberg transcription of original book
- Education and Doctoral Thesis ↗Center for Astrophysics | Harvard & Smithsonian
- Ionisation in the Solar Chromosphere ↗Philosophical Magazine; scan in the Saha Institute collected papers
- Collected Scientific Papers of Meghnad Saha: Ionisation in the Solar Chromosphere ↗Saha Institute of Nuclear Physics
Portrait credit
Unknown photographer. Public domain (Commons file-specific copyright declaration). Via Wikimedia Commons.
Photograph. Cropped to 4:5, resized to 320 × 400 and converted to WebP.
Image source & identification ↗ · Public domain (Commons file-specific copyright declaration) ↗
