DTemp

The LBL team has published an update on the method presented in Artigau et al. 2022. In addition to projecting against velocity derivatives, we project against temperature derivatives. This additions allows one to measure very accurate changes in effective temperature of stars. The details are presented in Artigau et al. 2024.  One necessary element is what we call the temperature gradient vector. These have been computed with HARPS and SPIRou for their respective domains. We hope to have in the near-future a full coverage from ~360nm to 2.5µm. The gradient spectra derived from HARPS and SPIRou data are merged together into a single spectrum per temperature bin. 

By default we add the 3500K (no v sin i) gradient spectra to the wrap files (if run using lbl_setup) to enable Dtemp you just need to uncomment the following lines:

rparams['RESPROJ_TABLES'] = dict()

rparams['RESPROJ_TABLES']['DTEMP3000'] = 'temperature_gradient_3500.fits'

Once these lines are uncommented all "no v sin i gradient spectra" are downloaded into the {DATA_DIR}/models directory (when you next run the wrap script).

Note if you do not uncomment these lines you will see no models in the {DATA_DIR}/models directory.

For all other models please download manually using the links below.

Don't forget to extract these files (as they are compressed in a tar file)

Note DTEMP temperates are not the same as the OBJECT_TEFF parameter (see here for explanation)

The current models for the gradient spectra are available for download:

Per temperature bin with rotational broadening from 0 to 19 km/s and without broadening for the full temperature range:

• 3000 - 6000  K [no v sin i]

• 3000 K [v sini 0-19 km/s]

• 3500 K [v sini 0-19 km/s]

• 4000 K [v sini 0-19 km/s]

• 4500 K [v sini 0-19 km/s]

• 5000 K [v sini 0-19 km/s]

• 5500 K [v sini 0-19 km/s]

• 6000 K [v sini 0-19 km/s]

The LBL wrap file seamlessly runs the DTEMP analysis. The simplest way is to use the 'wrap' files provided with the GitHub installation. Assuming that your target has a temperature of 3900K and a measured vsini=3.9 km/s, you would use the T=4000K gradient with a 4 km/s vsini. The temperature and vsini do not have to be an exact match and an should simply take the closest match. In that case, you would use the file temperature_gradient_model_4000vsini4kms.fits. 

These files are hosted in the 'models' folder within the LBL folders and you specify the output name within the rparams dictionnary.:

rparams['RESPROJ_TABLES'] = {'DTEMP4000vsini4kms': 'temperature_gradient_5000vsini4kms.fits'}

Please note these files above are tar files and you must extract them if you download them manually.

i.e.:  tar -xvf http://www.astro.umontreal.ca/~artigau/lbl/temperature_gradient_model_3000.tar