Pure rotational spectra of TiO and TiO_2 in VY Canis Majoris

Abstract

We report the first detection of pure rotational transitions of TiO and TiO_2 at (sub-)millimeter wavelengths towards the red supergiant VY CMa. A rotational temperature, T_rot, of about 250 K was derived for TiO_2. Although T_rot was not well constrained for TiO, it is likely somewhat higher than that of TiO_2. The detection of the Ti oxides confirms that they are formed in the circumstellar envelopes of cool oxygen-rich stars and may be the "seeds" of inorganic-dust formation, but alternative explanations for our observation of TiO and TiO_2 in the cooler regions of the envelope cannot be ruled out at this time. The observations suggest that a significant fraction of the oxides is not converted to dust, but instead remains in the gas phase throughout the outflow.

to appear in Astronomy and Astrophysics

References in corpus (6)

• The 3D Morphology of VY Canis Majoris. I The Kinematics of the Ejecta
• Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry
• The molecular envelope around the red supergiant VY CMa
• Submillimeter vibrationally excited water emission from the peculiar red supergiant VY CMa
• Aluminium oxide in the optical spectrum of VY Canis Majoris
• Discovery of a TiO emission band in the infrared spectrum of the S star NP Aurigae

Cited by in corpus (29)

• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• 2021 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• Dust formation in the oxygen-rich AGB star IK Tau
• Chemical equilibrium in AGB atmospheres: Successes, failures, and prospects for small molecules, clusters, and condensates
• PO and PN in the wind of the oxygen-rich AGB star IK Tau
• Laboratory and Astronomical Discovery of HydroMagnesium Isocyanide
• An observational study of dust nucleation in Mira ($o$ Ceti): I. Variable features of AlO and other Al-bearing species
• An Interferometric Spectral-Line and Imaging Survey of VY Canis Majoris in the 345 GHz Band
• An observational study of dust nucleation in Mira ($o$ Ceti): II. Titanium oxides are negligible for nucleation at high temperatures
• ALMA observations of TiO${}_2$ around VY Canis Majoris
• Circumstellar environment of the M-type AGB star R Dor. APEX spectral scan at $159.0-368.5$ GHz
• ALMA-resolved salt emission traces the chemical footprint and inner wind morphology of VY CMa
• Herschel SPIRE and PACS observations of the red supergiant VY CMa: analysis of the molecular line spectra
• The abundance of S- and Si-bearing molecules in O-rich circumstellar envelopes of AGB stars
• Rotational spectra of vibrationally excited AlO and TiO in oxygen rich stars
• Mass-independent analysis of the stable isotopologues of gas-phase titanium monoxide -- TiO
• New Measurements of the Radio Photosphere of Mira based on Data from the JVLA and ALMA
• The chemistry of dust formation in red supergiants
• Observational predictions for Thorne-Żytkow objects
• The Rotationally Resolved Infrared Spectrum of TiO and Its Isotopologues
• Non-Local thermal equilibrium spectra of atmospheric molecules for exoplanets
• Dust-forming molecules in VY Canis Majoris (and Betelgeuse)
• Multiple components in the molecular outflow of the red supergiant NML Cyg
• Betelgeuse and the red supergiants
• Protonated hydrogen cyanide as a tracer of pristine molecular gas
• Influence of the C/O ratio on titanium and vanadium oxides in protoplanetary disks
• High Resolution Laboratory Spectroscopy
• Molecules and Chemistry in Red Supergiants