ARCSAT ID NUMBER: AS06

DESCRIPTIVE TITLE: Monitoring H-alpha Variability in Be Stars in Young
Clusters

PI: Steven Souza (Williams College)

OBSERVER(S): Steven Souza

UNCERTIFIED/UNTRAINED OBSERVERS: possibly, students in our course
ASTR211: Astronomical 
Data Acquisition

COLLABORATORS: none
 
CONTACT INFORMATION: Steven Souza; ssouza@williams.edu; 413-441-9892

TIME REQUESTED: My request is for one week total during Q4. My
preference is to have
this in the form of one block of 3 nights and one of 4 nights, from
the following in
order of preference:
week of 12/7either half
week of 11/30second half only
week of 11/16second half only
week of 11/9either half
week of 11/2second half only
week of 10/26second half only

If scheduling split weeks proves too difficult, I can use any one full
week from the 
following in order of preference:
week of 12/7
week of 11/9

INSTRUMENT: SurveyCam

FILTERS: halpha_6563_50, rc_6450_50

COMMENTS: Some of this time may be used for our course ASTR211:
Astronomical Data Acquisition. In that case, I would like permission
to allow the students to operate the system, although I would be
present and supervise them at all times.

BRIEF SCIENCE JUSTIFICATION:

In Be stars both continuum and emission lines vary irregularly, but
spectroscopic monitoring has been undertaken for only a few individual
bright stars. A larger sample can be reached via narrowband imaging
using matched on-band (656nm) and off-band (645nm) filters, as we have
been doing on the Williams College 0.6-m DFM telescope since 2010.
Our program to monitor early-type emission-line stars is focused on
young open clusters and associations. To date we have characterized
H-alpha and continuum variations in 10 Be stars in NGC659 and NGC663,
found 4+ new Be stars and ~25 new candidate variables, found 2 new
candidate eclipsing binaries, and incidentally refined the orbital
period of an eclipsing binary in the Cygnus OB2 association.

Observations at ARCSAT, using a camera and filters similar to those we
use at Williams, are intended to add short periods of good temporal
coverage to complement the longer- term, but sparser, observations at
Williams. Many of the ~20 clusters in our target list can be observed
during any of the periods requested.