Transcript BRITE-Constellation

BRITE: BRight Target Explorer, 3 Countries: AUSTRIA – CANADA – POLAND, 6 Satellites
BRITE-Constellation
consists of six nano-satellites: UniBRITE and
BRITE-AUSTRIA (TUGSAT-1) are funded by
Austria, two more by Poland and the remaining
two satellites by the Canadian Space Agency.
Each will fly a CCD camera to perform highprecision, two-color photometry primarily of bright
stars, and continuously for two years or more.
BRITE-Constellation expects to observe on
average 20 stars simultaneously.
The primary science goals are studies of
massive stars in our Galactic neighborhood,
representing objects which dominate the ecology
of our Universe, and also highly evolved giant
stars of lower mass to probe the future development of our Sun. The operation policy will be to
observe a few fields over a long time span and
possibly some short runs in between, which will
assure optimum use of near polar low-earth orbits.
www.brite-constellation.at
LOGOS
BRITE-AUSTRIA
BRITE-POLAND
UniBRITE
Targets
are the 534 stars brighter than V = 4.0 mag and
with reduced accuracy also fainter stars. Typical
time scales for their variability range from an hour
to several weeks which calls for long and
uninterrupted data sets providing a frequency
resolution sufficient for astero-seismology.
AUSTRIA
POLAND
Figure: position of brightest stars (<= 4mag)
CANADA
The figure below shows the location of the bright
targets in the Hertzsprung-Russell Diagram
color-coded with the object types taken from the
VISAT database.
BRITE-Constellation reflects technology currently
developed in collaboration between Canada and
Austria. A launch of the first pair, UniBRITE and
BRITE-AUSTRIA, is planned in mid 2011 by a
PSLV from India.
The first Announcement of Opportunity for
submission of observing proposals has been
released in 2008 to the community and more than
40 proposals were submitted to the BRITE
Executive Science Team (BEST).
Satellites
Each of the 7kg BRITE nano-satellites is equipped
with a small dioptric telescope. A “constellation” of
satellites provides improved time coverage and
two-color information: one satellite carries a blue
and the other a red filter.
The 20cm cube structure houses three orthogonal
reaction wheels and three magnetorquer coils for
three-axis attitude control. Attitude determination is
provided by a magnetometer, six sun sensors and
a star tracker. This equipment will enable pointing
accuracy to better than one degree, attitude determination to one arcminute or better, and attitude
stability down to one arcminute rms.
Figure: HRD of the brightest stars (<= 4mag)
Instrument
The science payload of the satellite consists of a
five-lens telescope with an aperture of 30mm
and an interline CCD detector (KAI 11002-M)
from Kodak with 11M (4008x2672) pixels, along
with a baffle to reduce stray light. The instrument
has a resolution of 26.5 arcseconds per pixel and a
field-of-view of 24 degrees.
BRITE Filters
The effective wavelength range of the UniBRITE
instrument will be defined by a red filter covering
550-700nm, and the BRITE-AUSTRIA instrument
by a blue filter covering 390-460nm.
Ground stations
Up to 400 data sets will be obtained from a target
field per day and transmitted via ground stations
located in Graz, Vienna, Toronto and Warsaw.
Figure: BRITE telescope and CCD
Figure: BRITE BLUE and RED Filter transmission
Figure: BRITE ground station at the TUG Graz
Poster Design: Rainer Kuschnig, Alex Kaiser, Werner W. Weiss, Institute for Astronomy University Vienna, Austria
Contact: [email protected]