M78: an active region of star formation in the dark cloud Lynds 1630.

Several luminous stars in the dark cloud (Li 630) containing M78 (NOC 2068) are found to have ages as young as a few times i0 years. The properties of the stellar population apparently associated with this dark cloud are investigated; it appears that star formation has taken place over a period of several million years. A significant number of heavily obscured (A > 10 mag) stars has been found in the course of a 2- survey of selected regions in the Li 630 cloud complex. These objects appear best interpreted as stars of late B and early A spectral type embedded within the dense cloud material. The ratio of total to selective extinction achieves values as high as 5.8 in Li 630; furthermore, the ratio of A4430 band strength to visible extinction is anomalously low in this dense cloud complex. Sabject headings: infrared sources interstellar extinction - nebulae, individual - pre-main-sequence stars - star formation