Caroline’s rose (open Star cluster) – NGC 7789

Caroline’s rose (open Star cluster) – NGC 7789

10/24/24, 10/14/25

NGC 7789, popularly known as Caroline’s Rose (or the White Rose Cluster), is a richly populated open star cluster in the constellation Cassiopeia, set in a dense Milky Way starfield. It was discovered in 1783 by Caroline Herschel, and its nickname comes from the way its looping star chains and dark lanes can resemble a rose in bloom when viewed through a telescope or in deep images.

The cluster lies about 7,600–8,000 light-years from Earth and is an intermediate-age to old open cluster at roughly ~1.6–1.7 billion years. That age is a big part of its charm: many of its original hot, massive blue stars have long since evolved away, leaving a prominent population of cooler yellow/orange giants mixed among a dense spray of fainter main-sequence stars.

Scientifically, NGC 7789 is a valuable “testbed” for stellar evolution and cluster dynamics because it has survived for well over a billion years while remaining a coherent group in the galactic disk. Detailed photometric and spectroscopic studies of its evolved stars help refine estimates of cluster age, distance, and chemical composition, and provide real-world checks on models of how stars change as they exhaust core hydrogen and move onto later evolutionary stages.

Sources & references

• Wikipedia — “NGC 7789” (distance, age, alternate names, discovery notes). Wikipedia
• SEDS (Students for the Exploration and Development of Space) — “NGC 7789” background and observing notes. messier.seds.org
• Astronomy Magazine — “Deep-Sky Dreams: NGC 7789” (distance and age; observing context). Astronomy
• Astropix — “NGC 7789” (summary stats like magnitude/size; age/distance overview). astropix.com
• Wu et al. (2007), The Astronomical Journal — BATC photometry results for NGC 7789 (age/distance modulus constraints). Astrophysics Data System
• Overbeek et al. (2015), The Astronomical Journal — high-resolution spectroscopy of giants in NGC 7789 (cluster chemical/stellar characterization). Astrophysics Data System

Astrophotography