Hot-subdwarf atmospheric parameter prediction & spectrum fitting

The computing capability behind our survey spectral analysis, offered as an online service: forward prediction returns in milliseconds; inverse fitting gives parameter posteriors. Sign up to use it.

Two Capabilities

Parameters → Spectrum

Enter Teff, log g and helium abundance; get a theoretical spectrum in milliseconds.

Open the tool →

Spectrum → Parameter posteriors

Upload an observed spectrum; we sample posteriors against an NLTE synthetic-spectrum grid via χ² MCMC.

Open the tool →

Precision & Provenance

730 K Teff mean absolute error

0.09 dex log g mean absolute error

0.03 dex log(nHe/nH) mean absolute error

Note: The figures below are test-set results of the published paper (arXiv:2512.20185) and do not represent measured online precision of this service (online data distributions and SNRs differ). arXiv:2512.20185

Example Replay

Pre-computed example for understanding the output — not submittable.

Teff 36000 K · log g 5.30 · log(nHe/nH) −2.20 → Parameters → Spectrum

Observed + Best fit → Spectrum → Parameter posteriors

Quotas (daily, reset at 00:00 Beijing time)

Quotas (daily, reset at 00:00 Beijing time)
Role	Predictions / day	Fits / day	Extras
Guest	—	—	Overview, examples & docs
Registered user	20	3	Job history, CSV/JSON export
Group / authorized	200	20	Higher quotas, Token access, job records kept for 7 days
Admin	Unlimited	Unlimited	Queue monitoring, user management, model versions

Terms Summary

Non-commercial research use; cite as below when using results.
Uploaded spectra and job artifacts are automatically removed after 7 days.
Registration collects only email and an optional affiliation; spectra are used only for the requested computation.

How to Cite

Cite this service (default)

Lei Lab · Hot-subdwarf atmospheric parameter prediction & spectral fitting service, Model version v0.2.0-mock (2026-10-24), https://astro.xtu.edu.cn

Method paper: Lei et al. 2026, ApJS (arXiv:2512.20185)

The service paper is not yet published: the citation slot defaults to the tool version; the method is credited to the published paper. No previews of unpublished work.