Download E 3.1 Notes addition The James Webb and MOST Telescope

The James Webb Space Telescope
The successor to the Hubble Space Telescope
The James Webb Space Telescope will be launched into space at
the beginning of the next decade. It will be placed into an orbit
1.5 million kilometres above Earth in such a way that it will be in
constant alignment over the dark (nighttime) side of the planet.
This distance is far enough that the satellite will not be affected
by space debris and its orbiting position will protect it from light
reflected by the Earth. However, it is too far to be repaired and
maintained by astronauts, so its life span will only be 5 to 10
years.
The observatory bears the name of James Edwin Webb, director of NASA from 1961 to 1968. It
is the product of a collaborative effort between the United States, Canada and Europe. John
Hutchings, an astronomer with the Herzberg Institute of Astrophysics, is Canada’s Project
Scientist.
At 6.5 metres in diameter, the mirror of the telescope will have a surface seven times greater than
that of its predecessor, the Hubble Space Telescope (2.4-metre mirror). The mirror will consist of
18 small hexagonal mirrors that will deploy and fit together once the telescope is in orbit. The
entire observatory will weigh 6,600 kilograms.
The telescope will operate at wavelengths between 28 thousandths to 6 millionths of a
centimetre: that is, from the mid-range of the infrared to almost the beginning of visible red light
(Hubble, in contrast, observes at ultraviolet, visible and near-infrared wavelengths). This range
of wavelengths will make it possible to detect extrasolar planets, to conduct detailed studies into
the formation of planets and stars, and to study the oldest galaxies lying at the edges of the
Universe.
Canada is committed to providing a fine guidance sensor and a near-infrared camera. The fine
guidance sensor will allow the space observatory to be aimed at its targets with a high degree of
precision. Canadian researchers are also part of the American and European teams in charge of
designing other instruments for the space telescope.
The MOST Space Telescope
The first space telescope entirely of Canadian designed and
construction
The MOST Space Telescope (which stands for Microvariability and
Oscillation of Stars) was launched into space in 2003. It is the first
Canadian scientific satellite in orbit in 33 years, and it is the first space
telescope to be entirely designed and built in Canada.
MOST is a small telescope dedicated entirely to asteroseismology, which
is the study of star vibrations (pulsations). There is a great interest for
studying stellar vibrations because they allow scientists to obtain
information about the internal structure of a star, and thus about its size,
mass and composition.
The projected was initiated in 1996 by a group of researchers: Slavek Rucinski of Ontario’s
Centre for Research in Earth and Space Technology, Jaymie Matthews of the University of
British Colombia, Tony Moffat of the University of Montreal, and Kieran Carroll of Dynacon
Enterprises. In 1997, the Canadian Space Agency agreed to finance the project and Jaymie
Matthews was named Principal Investigator and Mission Scientist.
About the size and shape of a large suitcase, the satellite weighs only 54 kilograms and is
equipped with an ultra high precision telescope that measures only 15
centimetres in diameter. Despite its diminutive size, it is ten times more
sensitive than the Hubble Space Telescope in detecting the minuscule
variations in a star’s luminosity caused by vibrations that shake its
surface.
The telescope will complete one orbit around the Earth every 101
minutes by passing over each of Earth’s poles. It will spend 60 days on
each star studied. Its predicted life expectancy is 5 to 10 years.
The first major discovery made by the telescope occurred as soon as it
became operational. The discovery was that Procyon, one of the most
studied stars, shows no pulsations at all, which contradicts 20 years of ideas and observations,
and forced astronomers to rethink their models for stars.
In 2005, MOST was responsible for another surprising discovery: it observed a giant planet that
orbits so close to its host star that the star was forced to synchronize its rotation with that of the
planet. Normally, it is the other way around: a planet synchronizes its orbit with that of its host
star.