BRITE-Constellation: Nanosatellites for precision photometry of bright stars
- Author(s)
- W. W. Weiss, A. F. J. Moffat, A. Schwarzenberg-Czerny, O. F. Koudelka, C. C. Grant, R. E. Zee, R. Kuschnig, St. Mochnacki, S. M. Rucinski, J. M. Matthews, P. Orleański, A. A. Pamyatnykh, A. Pigulski, J. Alves, M. Guedel, G. Handler, G. A. Wade, A. L. Scholtz
- Abstract
BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is
an international nanosatellite mission to monitor photometrically, in
two colours, brightness and temperature variations of stars brighter
than V ~ 4, with precision and time coverage not possible from the
ground. The current mission design consists of three pairs of 7 kg
nanosats (hence ``Constellation'') from Austria, Canada and Poland
carrying optical telescopes (3 cm aperture) and CCDs. One instrument in
each pair is equipped with a blue filter; the other, a red filter. The
first two nanosats (funded by Austria) are UniBRITE, designed and built
by UTIAS-SFL (University of Toronto Institute for Aerospace
Studies-Space Flight Laboratory) and its twin, BRITE-Austria, built by
the Technical University Graz (TUG) with support of UTIAS-SFL. They were
launched on 25 February 2013 by the Indian Space Agency, under contract
to the Canadian Space Agency.
Each BRITE instrument has a wide field of view (~ 24 degrees), so up to
15 bright stars can be observed simultaneously in 32 × 32
sub-rasters. Photometry (with reduced precision but thorough time
sampling) of additional fainter targets will be possible through
on-board data processing. A critical technical element of the BRITE
mission is the three-axis attitude control system to stabilize a nanosat
with very low inertia. The pointing stability is better than 1.5
arcminutes rms, a significant advance by UTIAS-SFL over any previous
nanosatellite.
BRITE-Constellation will primarily measure p- and g-mode pulsations to
probe the interiors and ages of stars through asteroseismology. The
BRITE sample of many of the brightest stars in the night sky is
dominated by the most intrinsically luminous stars: massive stars seen
at all evolutionary stages, and evolved medium-mass stars at the very
end of their nuclear burning phases (cool giants and AGB stars). The
Hertzsprung-Russell diagram for stars brighter than mag V=4 from which
the BRITE-Constellation sample will be selected is shown in Fig. 1. This
sample falls into two principal classes of stars:
(1) Hot luminous H-burning stars (O to F stars). Analyses of OB star
variability have the potential to help solve two outstanding problems:
the sizes of convective (mixed) cores in massive stars and the influence
of rapid rotation on their structure and evolution.
(2) Cool luminous stars (AGB stars, cool giants and cool supergiants).
Measurements of the time scales involved in surface granulation and
differential rotation will constrain turbulent convection models.
Mass loss from these stars (especially the massive supernova
progenitors) is a major contributor to the evolution of the interstellar
medium, so in a sense, this sample dominates cosmic ``ecology'' in terms
of future generations of star formation. The massive stars are believed
to share many characteristics of the lower mass range of the first
generation of stars ever formed (although the original examples are of
course long gone).
BRITE observations will also be used to detect some Jupiter- and even
Neptune-sized planets around bright host stars via transits, as expected
on the basis of statistics from the Kepler exoplanet mission. Detecting
planets around such very bright stars will greatly facilitate their
subsequent characterization. BRITE will also use surface spots to
investigate stellar rotation.
The following Table summarizes launch and orbit parameters of
BRITE-Constellation components.
The full version of this paper describing in more detail
BRITE-Constellation will be published separately in a journal. The
symposium presentation is available at
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- University of Montreal, Polish Academy of Sciences (PAS), Technische Universität Graz, University of Toronto, Royal Military College of Canada, Technische Universität Wien
- Volume
- 301
- Pages
- 67-68
- DOI
- https://doi.org/10.1017/S1743921313014105
- Publication date
- 02-2014
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/b6a6e2d5-90f1-41b1-b66c-ac682c47e319