Detection of interstellar 1-cyanopyrene: A four-ring polycyclic aromatic hydrocarbon

Area of Science:

• Astrochemistry
• Interstellar Medium Studies
• Organic Molecule Detection

Background:

• Polycyclic Aromatic Hydrocarbons (PAHs) are abundant in space, evidenced by infrared emissions.
• Despite abundance, only a few specific PAHs have been identified in the interstellar medium.
• Detecting specific PAHs is crucial for understanding interstellar organic chemistry.

Purpose of the Study:

• To detect specific polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium.
• To investigate the abundance and formation pathways of pyrene derivatives.
• To understand the role of PAHs in the chemical evolution of the interstellar medium and carbon delivery.

Main Methods:

• Radio observations using the Green Bank Telescope.
• Targeted detection of 1-cyanopyrene, a derivative of pyrene.
• Analysis of spectral data to determine molecular column density.

Main Results:

• Successful detection of 1-cyanopyrene in the dense interstellar cloud TMC-1.
• Measured column density of 1-cyanopyrene: [Formula: see text] cm^-2.
• Estimated that pyrene constitutes up to 0.1% of the carbon in TMC-1.

Conclusions:

• The abundance of 1-cyanopyrene suggests that interstellar PAH chemistry favors pyrene formation.
• PAHs originating in cold molecular clouds may be a significant source of carbon for young planetary systems.
• This discovery provides insights into the chemical processes governing the composition of the interstellar medium.