Artist's conception of the newly discovered planet orbiting a brown dwarf "star"
Click on image for full size
NASA's Exoplanet Exploration Program
Small Planet, Small Star
News story originally written on June 2, 2008
If there are other planets in the Universe that are like Earth, then they might be places where life could survive. However, the search for planets like Earth is not easy. Most of the planets found outside of our solar system are not like Earth because they are huge - much more massive than Earth.
But now astronomers searching the Universe through telescopes have discovered a small planet about 3000 light years away. Itís the smallest planet ever found that is orbiting a normal star - only three times more massive than Earth.
The star that it orbits is not large. It is perhaps one-twentieth the mass of our Sun. Finding a small planet orbiting a small star suggests that small stars may be good places to look for other small planets.
The small star might, like our Sun, be massive enough to have nuclear reactions in its core. Or it may not have enough mass for the nuclear reactions and instead be an object called a brown dwarf.
The first measurements of the new planet and its star were made by astronomers in New Zealand and then researchers in Chile made more observations. Scientists around the world examined the data.
To find a small planet, the astronomers needed a special way of searching the skies. They used a method called gravitational microlensing, which can find planets as small as one-tenth the mass of Earth. The technique, relies on Einsteinís idea from his General Theory of Relativity that the gravity of a star acts like a giant magnifying glass making a little planet orbiting the star appear larger through the astronomerís telescopes.
Michael Briley, astronomer with the National Science Foundation, says that the discovery of this small planet "is another important step in the search for terrestrial planets in the habitable zones of other stars."
Last modified June 6, 2008 by Lisa Gardiner.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, as well as books
on science education!
You might also be interested in:
Do you know what a planet is? If so, you are doing better than professional astronomers! Right now astronomers aren't quite sure how to define a planet. Maybe you've heard that some astronomers think Pluto...more
Would it be more difficult to pull an elephant or a mouse? If you pulled each animal with the same amount of force, the elephant would respond less to pulling, even if he didnít pull back at all. Thatís...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. "The data will help give us a better road map to what a future...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core, and makes up about 84 percent of the Earth's volume. The mantle is made up of many distinct portions or...more
Some geologic faults that appear strong and stable, slip and slide like weak faults, causing earthquakes. Scientists have been looking at one of these faults in a new way to figure out why. In theory,...more
The sun goes through cycles that last approximately 11 years. These solar cycle include phases with more magnetic activity, sunspots, and solar flares. They also include phases with less activity. The...more
Studying tree rings doesn't only tell us the age of that tree. Tree rings also show what climate was like for each year of a tree's life, which means they can tell us about climates of the past and about...more