Astronomers have been puzzling over how to classify brown dwarfs since they were first discovered in 1995. So far, observations have shown that they fall somewhere between stars and planets in terms of mass, temperature, luminosity, and other properties. Two new studies lend insight into the formation of brown dwarfs and indicate that these mysterious objects are more like failed stars than planets.

To learn about other recent astronomical discoveries, visit the Science Bulletins website.

Like Earth, Jupiter has auroras that gleam at its poles—a result of the planet’s magnetic field interacting with energetic particles streaming from the Sun. In recent years astronomers have noticed that Ganymede and Io, two of Jupiter’s moons, each add their own personal stamp to the planet’s auroras. Pick out these planetary footprints in Jupiter’s swirling aurora on an image series from the Hubble Space Telescope in the newest Astro Bulletin, below.

Check out some of the archaeological traces in Andromeda Galaxy in the recent Astro Bulletin below.

To learn about other recent astronomical discoveries, visit the Science Bulletins website.

At long last, two teams of scientists have directly glimpsed the feeble light of planets orbiting distant stars through the lenses of telescopes. Before now, all of the 325 planets discovered outside our solar system had been located by indirect means, such as measuring their gravitational effects on their host star. The two teams used enhanced optical techniques to bring the planets into view. One group, led by Paul Kalas of the University of California-Berkeley, used the Hubble Space Telescope to block the blinding light of the star Fomalhaut to resolve a planet orbiting in the star's surrounding disk of dust. The other group, a Canadian team led by Christian Marois of the Herzberg Institute of Astrophysics in British Columbia, saw not one but three planets around the star HR 8799. They used a method called adaptive optics to sharpen an Earth-based telescope image enough to spot the planetary system. Now, scientists can scan the light from these planets to learn what they are made of, their temperatures, and other intriguing details.

See more images behind the new discoveries in the latest AMNH Astro Bulletin.