Small comets: Implications for interplanetary Lyman α

If small comets are as numerous in the inner solar system as Frank et al. [1986a] have recently proposed, large and easily detectable amounts of hydrogen would be generated in interplanetary space. Inhibition of water vapor production by a factor of 3 × 10−9 by very thick dust mantles would be necessary to prevent excitation of a detectable interplanetary Lyman α glow. Other optical problems associated with the cometesimals are also discussed.