Hot Corinos Chemical Diversity: Myth or Reality?

Abstract

After almost 20 years of hunting, only about a dozen hot corinos, hot regions enriched in interstellar complex organic molecules (iCOMs), are known. Of them, many are binary systems with the two components showing drastically different molecular spectra. Two obvious questions arise. Why are hot corinos so difficult to find and why do their binary components seem chemically different? The answer to both questions could be a high dust opacity that would hide the molecular lines. To test this hypothesis, we observed methanol lines at centimeter wavelengths, where dust opacity is negligible, using the Very Large Array interferometer. We targeted the NGC 1333 IRAS 4A binary system, for which one of the two components, 4A1, has a spectrum deprived of iCOMs lines when observed at millimeter wavelengths, while the other component, 4A2, is very rich in iCOMs. We found that centimeter methanol lines are similarly bright toward 4A1 and 4A2. Their non-LTE analysis indicates gas density and temperature ($\ge 2\times 10^6$ cm${}^{-3}$ and 100--190 K), methanol column density ($\sim 10^{19}$ cm${}^{-2}$) and extent ($\sim$35 au in radius) similar in 4A1 and 4A2, proving that both are hot corinos. Furthermore, the comparison with previous methanol line millimeter observations allows us to estimate the optical depth of the dust in front of 4A1 and 4A2, respectively. The obtained values explain the absence of iCOMs line emission toward 4A1 at millimeter wavelengths and indicate that the abundances toward 4A2 are underestimated by $\sim$30\%. Therefore, centimeter observations are crucial for the correct study of hot corinos, their census, and their molecular abundances.

9 pages, 3 figures, 2 Tables - Published in ApJ Letters

References in corpus (17)

• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• Constraining the abundances of complex organics in the inner regions of solar-type protostars
• Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions
• Grain growth in the envelopes and disks of Class I protostars
• The formation of ethylene glycol and other complex organic molecules in star-forming regions
• Formation and Atmosphere of Complex Organic Molecules of the HH 212 Protostellar Disk
• Complex organics in IRAS 4A revisited with ALMA and PdBI: Striking contrast between two neighbouring protostellar cores
• L483: Warm Carbon-Chain Chemistry Source Harboring Hot Corino Activity
• Discovery of a Hot Corino in the Bok Globule B335
• Low dust emissivities and radial variations in the envelopes of Class 0 protostars: a signature of early grain growth?
• First Abundance Measurement of Organic Molecules in the Atmosphere of HH 212 Protostellar Disk
• Glycolaldehyde in Perseus young solar analogs
• Implications of a hot atmosphere/corino from ALMA observations towards NGC1333 IRAS 4A1
• Deuterated methanol on Solar System scale around the HH212 protostar
• Complex organic molecules during low-mass star formation: Pilot survey results
• Organic complexity in protostellar disk candidates
• The Infall Motion in the Low-Mass Protostellar Binary NGC 1333 IRAS 4A1/4A2

Cited by in corpus (43)

• The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars
• CORINOS I: JWST/MIRI Spectroscopy and Imaging of a Class 0 protostar IRAS 15398-3359
• Complex organic molecules in low-mass protostars on solar system scales -- I. Oxygen-bearing species
• Evolutionary study of complex organic molecules in high-mass star-forming regions
• FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5
• Seeds of Life in Space (SOLIS). X. Interstellar Complex Organic Molecules in the NGC 1333 IRAS 4A outflows
• CoCCoA: Complex Chemistry in hot Cores with ALMA. Selected oxygen-bearing species
• JOYS+: link between ice and gas of complex organic molecules. Comparing JWST and ALMA data of two low-mass protostars
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A Hot Corino Survey toward Protostellar Cores in the Orion Cloud
• The two hot corinos of the SVS13-A protostellar binary system: counterposed siblings
• The Physical Properties of the SVS 13 Protobinary System: Two Circumstellar Disks and a Spiraling Circumbinary Disk in the Making
• The young protostellar disk in IRAS16293-2422 B is hot and shows signatures of gravitational instability
• The Perseus ALMA Chemical Survey (PEACHES). III. Sulfur-bearing species tracing accretion and ejection processes in young protostars
• Successive deuteration in low-mass star-forming regions: the case of D${}_2$-methanol (CHD${}_2$OH) in IRAS 16293-2422
• Importance of source structure on complex organics emission. I. Observations of CH${}_3$OH from low-mass to high-mass protostars
• Importance of source structure on complex organics emission II. Can disks explain lack of methanol emission from some low-mass protostars?
• Dust hot spots at 10 au scales around the Class 0 binary IRAS 16293-2422 A: a departure from the passive irradiation model
• Complex organic molecules detected in twelve high-mass star-forming regions with Atacama Large Millimeter/submillimeter Array (ALMA)
• Hot methanol in the [BHB2007] 11 protobinary system: hot corino versus shock origin? : FAUST V
• ALMA view of the L1448-mm protostellar system on disk scales: CH${}_3$OH and H${}^{13}$CN as new disk wind tracers
• Importance of source structure on complex organics emission III. Effect of disks around massive protostars
• A deep search for large complex organic species toward IRAS16293-2422 B at 3 mm with ALMA
• FAUST VI. VLA 1623--2417 B: a new laboratory for astrochemistry around protostars on 50 au scale
• FAUST VII. Detection of A Hot Corino in the Prototypical Warm Carbon-Chain Chemistry Source IRAS 15398-3359
• FAUST XX. The chemical structure and temperature profile of the IRAS 4A2 hot corino at 20-50 au
• PRODIGE -- envelope to disk with NOEMA. IV. An infalling gas bridge surrounding two Class 0/I systems in L1448N
• SO2 and OCS toward high-mass protostars: A comparative study between ice and gas
• ALMA ACA study of the H${}_2$S/OCS ratio in low-mass protostars
• Tracking the ice mantle history in the Solar-type Protostars of NGC 1333 IRAS 4
• Core to ultracompact HII region evolution in the W49A massive protocluster
• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• FAUST XV. A disk wind mapped by CH${}_3$OH and SiO in the inner 300 au of the NGC 1333 IRAS 4A2 protostar
• Identification of hot gas around low-mass protostars
• PRODIGE - envelope to disk with NOEMA: V. Low 12C/13C ratios for CH3OH and CH3CN in hot corinos
• The first interferometric measurements of NH${}_2$D/NH${}_3$ ratio in hot corinos
• A deep search for Complex Organic Molecules toward the protoplanetary disk of V883 Ori
• FAUST. XXVIII. High-Resolution ALMA Observations of Class 0/I Disks: Structure, Optical Depths, and Temperatures
• MAGellanic Outflow and chemistry Survey (MAGOS): Hot cores in the LMC
• HOPS-288: A Laboratory for Complex Organics in Proto-multiple Systems
• FAUST XXV. A potential new molecular outflow in [BHB2007] 11
• Hunting for methanol in the water rich, planet forming disk around HL Tau
• The chemical nature of Orion protostars: Are ORANGES different from PEACHES? ORANGES II
• Exploring the 100 au Scale Structure of the Protobinary System NGC 2264 CMM3 with ALMA