UKRI-STFC funded · 2021–2028
The Red Giant Survey is a seven-year collaborative programme across nine UK universities, using ground-based spectroscopy and space-borne photometry to trace stellar evolution from the first ascent of the red-giant branch through to planetary nebula ejection.
When a Sun-like star exhausts the hydrogen in its core, it swells into a red giant — a transformation that will eventually consume its inner planets and eject its outer layers as a planetary nebula. The Red Giant Survey is built around a single question: how does that mass leave the star, and what does it carry with it?
Our programme combines high-resolution optical spectroscopy from the William Herschel Telescope, long-baseline radio interferometry from e-MERLIN, and photometric time-series from the TESS and Gaia satellites, applied to a volume-limited sample of 4 800 evolved giant stars within 1 kiloparsec of the Sun.
The results feed directly into models of chemical enrichment. Red giants are primary factories for carbon, nitrogen, and s-process elements in the Milky Way. Our distance-ladder calibrations will tighten constraints on H₀ across the Local Group and beyond.
Determining how stars shed their envelopes on the RGB and AGB, using spectroscopic wind signatures alongside mid-IR excess from circumstellar dust.
Long-baseline photometric monitoring of semi-regular and Mira variables to link pulsation period to mass-loss efficiency and surface chemical composition.
Tracing dredge-up of carbon, lithium, and s-process elements through precise abundance analyses from the RGB tip to the thermal-pulse AGB.
Using the RGB tip as a standard candle, cross-calibrating with Gaia parallaxes to tighten constraints on H₀ in the Local Volume.
Spectropolarimetric monitoring with NARVAL and HARPSpol to map large-scale field geometries and assess their role in driving chromospheric winds.
A parallel survey in the Magellanic Clouds and outer halo to understand how mass-loss rates and dust production scale with metallicity.
Line-strength indices for six survey targets observed this season with WHT/ISIS. Indices are normalised to μ Cep as the programme reference star.
Access full data archive →| Star | Type | Hα EW | TiO strength | Rel. |
|---|---|---|---|---|
| μ Cep | M2 Ia | −14.2 Å | 1.00 | |
| α Her | M5 Ib-II | −8.7 Å | 0.81 | |
| Betelgeuse | M2 Iab | −12.1 Å | 0.93 | |
| W Cyg | M4-7e | −22.4 Å | 0.64 | |
| RS Cnc | M6 III | −18.9 Å | 0.48 | |
| R Leo | M8 IIIe | −31.6 Å | 0.37 |
We welcome collaborations from UK and international institutions, proposals for complementary observing programmes, and applications from postdoctoral researchers and PhD students. All survey data is made publicly available through the ESO Phase 3 archive within 18 months of observation.