star_activity_halpha¶

H-alpha chromospheric activity index of a reduced stellar spectrum, after Gomes da Silva et al. (2011): the mean flux in a 1.6 Angstrom core over the sum of two nearby continuum bands. The red-arm companion of the Ca II H and K S index, usable on any spectrograph that covers H-alpha.

Conventions¶

1.6 Angstrom core centred on 6562.808 Angstrom, reference bands 6550.87 +/- 5.375 and 6580.31 +/- 4.375 Angstrom, as published; no free parameter. The spectrum must be in the star's rest frame to better than ~0.3 Angstrom (a barycentric correction alone is not enough for a high radial-velocity star: shift it first with doppler_shift if needed).

References¶

• Gomes da Silva et al. 2011, A&A 534, A30 - the H-alpha index bandpasses
• Boisse et al. 2009, A&A 495, 959 - the original H-alpha index definition

Variables¶

This recipe declares no variables: it runs as is.

Steps¶

Run it¶

spectro pipeline star_activity_halpha --input spectrum.fits
spectro preset show star_activity_halpha      # variables and steps

from spectro_kernel import WorkContext
from spectro_kernel.pipeline import PipelineBuilder

pipeline = PipelineBuilder().from_preset("star_activity_halpha").build()
result = pipeline.execute(ctx)        # ctx holds the spectrum / frames
print(result.history[-1])             # pipeline:<name> vX.Y.Z + variables

{
  "tool": "run_preset",
  "arguments": {
    "session_id": "<session_id>",
    "preset_name": "star_activity_halpha"
  }
}