  We investigate the young stellar objects (YSOs) in the Lynds~1641 (L1641)
cloud using multi-wavelength data including Spitzer, WISE, 2MASS, and XMM
covering ~1390 YSOs across a range of evolutionary stages. In addition, we
targeted a sub-sample of YSOs for optical spectroscopy. We use this data, along
with archival photometric data, to derive spectral types, extinction values,
masses, ages, as well as accretion rates. We obtain a disk fraction of ~50% in
L1641. The disk frequency is almost constant as a function of stellar mass with
a slight peak at log(M_*/M_sun)\approx-0.25. The analysis of multi-epoch
spectroscopic data indicates that the accretion variability of YSOs cannot
explain the two orders of magnitude of scatter for YSOs with similar masses.
Forty-six new transition disk (TD) objects are confirmed in this work, and we
find that the fraction of accreting TDs is lower than for optically thick disks
(40--45% vs. 77--79% respectively). We confirm our previous result that the
accreting TDs have a similar median accretion rate to normal optically thick
disks. We confirm that two star formation modes (isolated vs. clustered) exist
in L1641. We find that the diskless YSOs are statistically older than the YSOs
with optically-thick disks and the transition disk objects have a median age
which is intermediate between the two populations. We tentatively study the
star formation history in L1641 based on the age distribution and find that
star formation started to be active 2--3 Myr ago.
