IRAM Memo 2024-01 Planet brightness temperatures in ASTRO

# IRAM Memo 2024-01
Planet brightness temperatures in ASTRO

J. Boissier, J. Pety, S. Bardeau
1. IRAM (Grenoble);
2. Observatoire de Paris

Dec 06 , 2024
Version 1.0

### Abstract:

Planets are used as primary flux calibrator for both IRAM observatories. Planet brightness temperatures in ASTRO were not updated since their first implementation. The accuracy of the planet models have greatly improved over the past years to about 5% absolute accuracy, rendering it important to update ASTRO. We present in this report the comparison of the current implementation of planet brightness temperature in ASTRO to the results of more advanced models. We describe how we implement new models in ASTRO and what could be the impact on IRAM instrument calibration.

- Contents
- Introduction
- Definitions
  - Planet flux computation
  - Legacy implementation in ASTRO
  - 2024 implementation in ASTRO
    - Unchanged
    - Mars
    - Giant planets
  - Planet brightness temperatures in CASA
- Results
  - Telluric planets
    - Mars
    - Mercury
    - Venus
  - Giant Planets
    - Uranus
    - Neptune
    - Jupiter
    - Saturn
- Summary of the impact on instrument calibration
- Recommendation
- Acknowlegements
- About this document ...