Hifistars herschel/hifi observations of vy canis majoris : Molecular-line inventory of the envelope around the largest known star

  title={Hifistars herschel/hifi observations of vy canis majoris : Molecular-line inventory of the envelope around the largest known star},
  author={Javier Alcolea and Valent{\'i}n Bujarrabal and Pere Planesas and David Teyssier and Jos{\'e} Cernicharo and Elvire De Beck and Leen Decin and Carsten Dominik and K. Justtanont and A. de Koter and A. P. Marston and Gary J. Melnick and Karl M. Menten and David A. Neufeld and H. Olofsson and M. R. Schmidt and Fredrik Schoier and Ryszard Szczerba and L. B. F. M. Waters},
  journal={Astronomy and Astrophysics},
Aims. The study of the molecular gas in the circumstellar envelopes of evolved stars is normally undertaken by observing lines of CO (and other species) in the millimetre-wave domain. In general, the excitation requirements of the observed lines are low at these wavelengths, and therefore these observations predominantly probe the cold outer envelope while studying the warm inner regions of the envelopes normally requires sub-millimetre (sub-mm) and far-infrared (FIR) observational data… 

ALMA sub-mm maser and dust distribution of VY Canis Majoris

Aims. Cool, evolved stars have copious, enriched winds. Observations have so far not fully constrained models for the shaping and acceleration of these winds. We need to understand the dynamics

A λ 3 mm and 1 mm line survey toward the yellow hypergiant IRC +10420: N-rich chemistry and IR flux variations.

It is found that IRC +10420 presents high abundances of the N-bearing molecules compared with O-rich evolved stars, which supports the presence of a N-rich chemistry, expected for massive stars.

The Physics of Water Masers observable with ALMA and SOFIA: Model Predictions for Evolved Stars

We present the results of models that were designed to study all possible water maser transitions in the frequency range 0-1.91 THz, with particular emphasis on maser transitions that may be

A Search for Light Hydrides in the Envelopes of Evolved Stars

We report a search for the diatomic hydrides SiH, PH, and FeH along the line of sight toward the chemically rich circumstellar envelopes of IRC+10216 and VY Canis Majoris. These molecules are thought

Strong magnetic field generated by the extreme oxygen-rich red supergiant VY Canis Majoris

Evolved stars experience high mass-loss rates forming thick circumstellar envelopes (CSEs). The circumstellar material is made of the result of stellar nucleosynthesis and, as such, plays a crucial

Circumstellar ammonia in oxygen-rich evolved stars

The circumstellar ammonia (NH$_3$) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH$_3$ abundance in oxygen-rich stars is several orders of

The millimeter IRAM-30 m line survey toward IK Tau.

The detection of carbon bearing molecules like H2CO, as well as the discrepancies found between the derived abundances and the predictions from chemical models for some molecules, highlight the need for a revision of standard chemical models.

Further ALMA observations and detailed modeling of the Red Rectangle.

It is suggested that HCN is formed in a dense photodissociation region (PDR) due to the UV excess known to be produced by the stellar system, following chemical mechanisms that are well established for interstellar medium PDRs and disks orbiting young stars.

Investigation of recurrent EUV jets from highly dynamic magnetic field region

In this work, we present observations and interpretations of recurrent extreme ultraviolet (EUV) jets that occurred between 2012 July 1 21:00 UT and 2012 July 2 10:00 UT from the western edge of the



Herschel/HIFI observations of O-rich AGB stars : molecular inventory ⋆

Aims. Spectra, taken with the heterodyne instrument, HIFI, aboard the Herschel Space Observatory, of O-rich asymptotic giant branch (AGB) stars which form part of the guaranteed time key program

Herschel/HIFI observations of molecular emission in protoplanetary nebulae and young planetary nebulae

Aims. We aim to study the physical conditions, particularly the excitation state, of the intermediate-temperature gas in pro toplanetary nebulae and young planetary nebulae (PPNe, PNe). The

Herschel/HIFI observations of red supergiants and yellow hypergiants ⋆ , ⋆⋆ , ⋆⋆⋆ I. Molecular inventory

Context. Red supergiant stars (RSGs) and yellow hypergiant stars (YHGs) are believed to be the high-mass counterparts of stars in the asymptotic giant branch (AGB) and early post-AGB phases. As such,

Herschel/HIFI deepens the circumstellar NH3 enigma

Context. Circumstellar envelopes (CSEs) of a variety of evolved stars have been found to contain ammonia (NH3) in amounts that exceed predictions from conventional chemical models by many orders of

Polarisation observations of VY Canis Majoris H2O 532–441 620.701 GHz maser emission with HIFI

Context. Water vapour maser emission from evolved oxygen-rich stars remains poorly understood. Additional observations, including polarisation studies and simultaneous observation of different maser

The Molecular Envelope around the Red Supergiant VY CMa

We present millimeter interferometric observations of the molecular envelope around the red supergiant VY CMa with the Submillimeter Array (SMA). The high angular resolution (<2'') allows us to

Fundamental properties and atmospheric structure of the red supergiant VY Canis Majoris based on VLTI/AMBER spectro-interferometry

Aims. We investigate the atmospheric structure and fundamental properties of the red supergiant VY CMa. Methods. We obtained near-infrared spectro-interferometric observations of VY CMa with spectral

Submillimeter vibrationally excited water emission from the peculiar red supergiant VY Canis Majoris

Context. Vibrationally excited emission from the SiO and H2O molecules probes the innermost circumstellar envelopes of oxygenrich red giant and supergiant stars. VY CMa is the most prolific known

Chemical complexity in the winds of the oxygen-rich supergiant star VY Canis Majoris

Observations of molecules in the oxygen-rich shell of the red supergiant star VY Canis Majoris suggest that oxygen- rich shells may be as chemically diverse as their carbon counterparts.


Observations of the carbon-bearing molecules CO, HCN, CS, HNC, CN, and HCO+ have been conducted toward the circumstellar envelope of the oxygen-rich red supergiant star, VY Canis Majoris (VY CMa),