Telluric absorption lines in the ALMA spectra of ? Car

The massive binary system formed by $\eta$ Car and an unknown companion is a strong source at millimetre submillimetre wavelengths. Close to the stars, continuum bremsstrahlung radio recombination lines originate in ionized wind of several compact sources high density plasma. Molecular are also detected these wavelengths, some them seen absorption towards emission region, many revealed ALMA observations. However, because atmospheric calibration performed low spectral resolution mode, telluric can still be present high-resolution spectra scientific products, which could lead false identification molecules. Since Carinae bright source, issue even more critical features highlighted. In this work, we explore three different sets archive data Car, including (0.065" x 0.043") observations recently published our group, verify real discuss their origin. We conclude that truly clouds close system, while others artifacts faulty elimination during procedure. found not phase calibrators they much weaker than where line appears intensity enhances small individual systematic errors.