Astrophysicists Ring In the New Year With Discovery of an Exo-Saturn
Fill in the blank. The discovery of a ringed planet orbiting 1SWASP J140747.93-394542.6 is ______.
So far, 2012 has been a great year for extrasolar planets, also known as exoplanets. In just the past two weeks, astrophysicists from NASA's Kepler mission have announced the discovery of the smallest exoplanet system to date and the discovery of two more dual-sun planet systems. Additionally, an international team of astronomers searching for planets using a microlensing technique has concluded that planets may outnumber stars in our galaxy.
However, a recent discovery by an international team of astronomers led by Eric E. Mamajek, Assistant Professor of Physics and Astronomy at the University of Rochester, is trumping all of these prior discoveries in sheer, unadulterated awesome.
This team has discovered what may be the first ringed planet orbiting another star.
One Ringed Exoplanet To Rule Them All
Located 420 light years away in the constellation Centaurus, 1SWASP J140747.93-394542.6 (J1407, for short) is a K5-type star sightly cooler and smaller than our Sun. It is also a very young star, estimated to be around 16 million years old.
The scientists were studying the light curves of young stars in a nearby star-forming region known as the Scorpius-Centaurus association, looking for dips in the light that would indicate an object passing in front of the star from our perspective. This is the same technique used by the NASA Kepler mission to observe transiting exoplanets.
The light curve the Rochester team found when analyzing the data from J1407 was highly unusual. Unlike the symmetrical U-shaped curves usually found when a planet candidate eclipses a star, this was an asymmetrical curve bracketed at the beginning and end with intermittent dimming periods. At the deepest point in the curve, some 95% of J1407's light was being obscured by the transiting object.
If You Accreted It, Then You Should Have Put a Ring On It
After ruling out the possibility that this unusual curve was caused by protoplanetary disk or other objects, the researchers concluded that this was most likely a young, low-mass planet with a giant ring system. Described by lead author Mamajek as "Saturn on steroids," J1407's ringed companion is estimated to have an orbital period of at least 850 days and is located more than 1.7 Astronomical Units from the star, 1 AU being the average distance from the Earth to the Sun.
Follow-up observations using the radial velocity, or wobble, method will be able to better determine the planet's mass and orbital period. Further study of this object may also provide some more general answers about the formation of planet and moon systems around infant stars.
If the first two weeks of 2012 are any indication, we're in for an amazing year of extrasolar finds.
- Kepler 22b-Our New Home Away From Home?
An article about the newly discovered star system, some 600 light years from earth, Kepler 22b. Background information about this planet is highlighted in the article as well.
- The Extrasolar Planets Encyclopaedia
- Saturn-like ring system eclipses Sun-like star
A team of astrophysicists has discovered a ring system in the constellation Centaurus that invites comparisons to Saturn. This is the first system of discrete, thin, dust rings detected around a very low-mass object outside of our solar system.
- Full text of the study at Arxiv.org
Eric E. Mamajek, Alice C. Quillen, Mark J. Pecaut, Fred Moolekamp, Erin L. Scott, Matthew A. Kenworthy, Andrew Collier Cameron & Neil R. Parley. Planetary Construction Zones in Occultation: Discovery of an Extrasolar Ring System Transiting a Youn