Molecules in the peculiar age-defying source IRAS 19312+1950
arXiv:2211.13640 · doi:10.1051/0004-6361/202244559
Abstract
Context. IRAS 19312+1950 is an isolated infrared source that exhibits a characteristic quasi-point-symmetric morphology in the near- and mid-infrared images and is also very bright in molecular radio lines. Because of its unique observational characteristics, various observational studies have been conducted and several hypotheses have been proposed regarding its origin, which is still unclear. So far, it has been suggested that it could be a peculiar evolved star, a young stellar object, or even a red nova remnant. Regardless of which type of object it is ultimately classified as, IRAS 19312+1950 is exceptionally bright in the infrared and molecular radio lines and therefore will undoubtedly be crucial as a prototype of this kind of object having a peculiar nature or unusual evolutionary phase. Aims. This study aims to reveal the molecular composition of the central part of IRAS 19312+1950 by performing an unbiased molecular radio line survey and discussing the origin of the object from a molecular chemical point of view. Methods. We carried out a spectral line survey with the IRAM 30 m telescope towards the center of IRAS 19312+1950 in the 3 and 1.3 mm windows. Results. In total, 28 transition lines of 22 molecular species and those isotopologues are detected towards IRAS 19312+1950, some of which exhibit a broad and a narrow components. Seventeen thermal lines and 1 maser line are newly detected. The molecular species of CO, SiO, HNC, HCO, HCO, and -CH are detected for the first time in this object. Conclusions. Our results, in combination with previous studies, favor the hypothesis that IRAS 19312+1950 might be a red nova remnant, in which the progenitors that merged to become a red nova may have contained at least two evolved stars with oxygen-rich and carbon-rich chemistry, respectively.
30 pages, 24 figures, accepted for publication in A&A
References in corpus (22)
- 2021 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
- ATLASGAL --- properties of a complete sample of Galactic clumps
- The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
- Revealing the physical properties of molecular gas in Orion with a large scale survey in J=2-1 lines of 12CO, 13CO and C18O
- ALMA Observations of Infalling Flows toward the Keplerian Disk around the Class I Protostar L1489 IRS
- The HNC/HCN Ratio in Star-Forming Regions
- HCN/HNC intensity ratio: a new chemical thermometer for the molecular ISM
- Lambda = 3 mm line survey of nearby active galaxies
- The millimeter IRAM-30m line survey toward IK Tau
- SiO in C-rich circumstellar envelopes of AGB stars: effects of non-LTE chemistry and grain adsorption
- Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud
- Nuclear ashes and outflow in the eruptive star Nova Vul 1670
- Structure and dynamics of the class I young stellar object L1489 IRS
- Organic molecules, ions, and rare isotopologues in the remnant of the stellar-merger candidate, CK Vulpeculae (Nova 1670)
- Correlation between Infrared Colors and Intensity Ratios of SiO Maser Lines
- Shaping the envelope of the asymptotic giant branch star W43A with a collimated fast jet
- Exploring HNC and HCN line emission as probes of the protoplanetary disk temperature
- A 3mm chemical exploration of small organics in Class I YSOs
- SiO maser astrometry of the red transient V838 Monocerotis
- In search of infall motion in molecular clumps III: HCO+ (1-0) and H13CO+ (1-0) mapping observations toward the confirmed infall sources
- On the nature of the enigmatic object IRAS 19312+1950: A rare phase of massive star formation?
- The GBT 67 -- 93.6 GHz Spectral Line Survey of Orion-KL