Which molecule radiates strongly in the millimeter wave regime, serving as a proxy for $ ext{H}_2$?
Answer
Carbon Monoxide ($ ext{CO}$)
Molecular hydrogen ($ ext{H}_2$) is the main reservoir for star formation, but it is challenging to observe directly due to the extremely cold temperatures prevalent in Giant Molecular Clouds (GMCs). To circumvent this observational difficulty, astronomers utilize trace amounts of other molecules that are readily detectable under these conditions. Carbon Monoxide ($ ext{CO}$) is the most notable proxy because it radiates efficiently in the millimeter wave spectrum. This strong emission allows researchers to accurately map the location and estimate the mass of the bulk cold gas supply ($ ext{H}_2$) available for future stellar births, although the conversion factor used introduces inherent uncertainties.
Related Questions
What is the primary component of Giant Molecular Clouds (GMCs)?What timescale does $ ext{UV}$ Luminosity ($L_{ ext{UV}}$) typically probe for star formation?Which molecule radiates strongly in the millimeter wave regime, serving as a proxy for $ ext{H}_2$?What process creates the characteristic red light of the $ ext{H} ext{alpha}$ line at $656.3 ext{ nm}$?In a galaxy undergoing steady-state star formation, what relationship should ideally exist between $L_{ ext{UV}}$ and total $L_{ ext{IR}}$?Which indicator traces star formation timescales significantly longer than $10^8$ years, representing the fuel supply?Which gas reservoir traces the *potential* for future star formation, observed via $21 ext{ cm}$ emission?What wavelength range specifically characterizes the Far-Infrared (FIR) useful for tracing dust re-radiation?What does a condition where $L_{ ext{UV}} ext{ extless extless} L_{ ext{IR}}$ strongly imply about current star formation?How does the energy absorbed by dust when blocking UV light manifest as a measurable output?