SIMBAD references

An ideal molecular probe for tracing the kinetic temperature in dense molecular cloud cores should allow the temperature determination to be independent of gas density effects. The formaldehyde (H₂CO) molecule, a slightly asymmetrical rotor, is just such a molecule. By using several sets of judiciously chosen H₂CO line ratios, we have reliably determined the gas kinetic temperatures of the dense gas condensations within the NGC 2024 star formation region. Our measurements indicate T_K>40 K toward the embedded sources FIR3-FIR7. These sources, which had previously been identified as isothermal protostars, are likely in a more evolved state.