Commission 42
IAU Commission 42 · Close Binary Stars
International Astronomical Union Commission 42 Close Binary Stars (1948-2015), originally Photometric Double Stars; successor science in Commission G1.
The IAU Past Scientific Groups archive lists Commission 42 Close Binary Stars with mandate dates 1948-2015. Established as Photometric Double Stars; renamed Close Binary Stars in 1970. After 2015 restructuring, Commission G1 Binary and Multiple Star Systems extends the science previously covered by Commission 26 and Commission 42.
What it supports
Exact hard institutional 42 in astronomy with a durable named scientific office and published Transactions reports. Catalogue and observer adjacency via binary-star catalogues and the Bibliography of Close Binaries.
What it does not
Not a claim that the IAU chose 42 for Deep Thought. Not every historical IAU commission number as a separate Index object. Not Flamsteed 42 Dra, Kepler-42, or live binary-adjacent shelf objects collapsed into this plate. Not Adams.
ExactnessExact
Form42
UnitIAU commission
Strengthhard
When1948-2015
Hung4 October 2026
Source
IAU Past Scientific Groups- IAU Commission G1
- Cambridge Core Transactions Commission 42 reports