Foundation models are beginning to impact stellar spectroscopy, where spectra encode rich physical information in a structured, language-like form. A key challenge is adapting these models across heterogeneous surveys with differing resolution and coverage. We apply Low-Rank Adaptation (LoRA) to fine-tune SpecCLIP--a contrastively pre-trained model on LAMOST and Gaia XP spectra--for downstream tasks on DESI Early Data Release (EDR) spectra. We show that LoRA enables few-shot learning on DESI, with performance varying by fine-tuned module and benefiting from Gaia XP knowledge embedded in the pre-trained model. Our results demonstrate that LoRA provides a lightweight and effective strategy for extending spectral foundation models to new instruments and survey domains.
Cite
@article{arxiv.2507.20972,
title = {Finetuning Stellar Spectra Foundation Models with LoRA},
author = {Xiaosheng Zhao and Yuan-Sen Ting and Alexander S. Szalay and Yang Huang},
journal= {arXiv preprint arXiv:2507.20972},
year = {2025}
}
Comments
7 pages, 2 figures. Accepted to the Machine Learning for Astrophysics (ML4Astro) Colocated Workshop at ICML 2025. Presented as a spotlight talk