Vulcan Camera Project Description

Introduction

The Vulcan Camera Project is sponsored by NASA Ames Research Center designed to detect large planets around other stars. Vulcan uses a technique called differential photometry to measure the amount of light coming from target stars in the Vulcan camera's wide field of view. The team employs a method called photometry which images light coming from target stars within a star field. If a large planet transits (passes across) the disk of a target star, the intensity of the star's light is reduced by a measurable amount. Periodic fluctuations in received light indicate a repeatable event associated with a target star. A periodic event with the characteristic "footprint" of a planetary transit indicates the presence of a large planet in orbit about the target star.

The Vulcan photometer employs a four-inch aperture telescope and CCD imager for demonstrating the scientific feasibility of the differential photometric technique in the search for extra-solar planets. Should transits be detected, it will provide impetus to the Kepler Project, a proposed space mission to orbit a one-meter aperture photometer to search for habitable planets around other stars.

Background

A knowledge of other planetary systems that includes information on the number, size, mass, and spacing of the planets around a variety of star types is needed to deepen our understanding of planetary system formation and processes that give rise to their final configurations. Recent discoveries show that many planetary systems are quite different from the solar system in that they possess giant planets in short-period orbits and that they often have highly eccentric orbits. Current theories predict that the size of the atmospheres of the short-period planets will vary with the mass of the planet and the size of the orbital semi-major axis because of the intense stellar insolation. To obtain information on the size, mass, density, and orbital parameters of the giant-inner planets and to develop the statistical dependencies of these, it is necessary to observe many of these objects for a variety of stellar spectral types and stellar compositions. Similarly the discoveries that binary stars also have low mass companions (Cochran et al.1997, Butler et al.1997), demand that many more objects must be discovered and studied so that the differences between planetary systems in single stars versus multiple star systems can be understood.

Objectives

The Vulcan Camera Project objectives are to:

determine the frequency of Saturn- and Jupiter-sized planets in inner orbits around a variety of stellar types,
determine the planet sizes and orbital semi-major axes,
determine the densities of those planets that can be observed with Doppler velocity techniques, and
correlate the characteristics of the discovered planets with stellar spectral type.

Why "Vulcan"

Vulcan

Vulcan was the Roman god of fire and the mythical inventor of smithing and metalworking. His legendary craftsmanship produced fine chariots, and was said to have created the weapons of Hercules and armor of Achilles. The word "volcano" derived from Vulcan, summons forth images of flames, extremely hot surfaces and fiery eruptions.

So it isn't surprising that conjecture in the mid 1800's of an unseen planet interior to the orbit of Mercury was given tne name "Vulcan". The planet Vulcan was the hypothetical construct of a 19th century French mathematician, Urbain Le Verrier, who attempted to explain the unpredictability of Mercury's orbit. Alleged sightings of this planet in 1859 inspired Le Verrier to mobilize all French and some other astronomers in 1860 to find Vulcan during a total solar eclipse. None did.

The popularity of Vulcan which originated in the late 19th century was quelled in 1916 when Albert Einstein published the General Theory of Relativity. Eistein's Theory explained the unpredictability of Mercury's orbit without invoking an additional planet.

Last Modified: 30October 2001