Calculations indicated that a body warm enough to hold liquid water would have to lie so close to a red dwarf that the planet would be forced to rotate in sync with the star. One side would always face the star, and the other would face away, creating climates that would be either boiling hot or freezing cold.

Last September the Hubble Space Telescope transmitted vivid photos from space of what could be the Milky Way's most luminous star. Astronomers have dubbed it "Pistol Star," for the gun shape of its nebula, or surrounding gaseous cloud.

1 Astrophysical Journal, Luhman and his colleagues used the Hubble Space Telescope to photograph an object, about 10 Jupiter masses, orbiting the star CHXR 73.

They detected increases in the brightness of stars in a nearby galaxy.

Theorists have come up with several explanations for the star's extraordinary behavior: a thermonuclear explosion on the star's surface, a collision with an unseen companion, the swallowing of one or more closely orbiting planets.

(That's young for a star, which can "live" for billions of years.)

Although the outbursts have made Eta Carinae a striking spectacle, astronomers have long regarded the star as a freak of nature.

That's a puzzle, says De Luca, because a 2,000-year-old neutron star born in isolation ought to be spinning thousands of times faster.

DARK TRACERS Streams arise when the Milky Way tugs on a nearby galaxy or star cluster.

Determining a star's mass and age requires an accurate measurement of its brightness, and in that endeavor the sharpness of the Hubble images is invaluable, notes Robberto.

Although the team may have uncovered a new kind of neutron star, theorist Robert Duncan of the University of Texas at Austin says that "a more reliable and conservative interpretation" is that the researchers have detected elderly rotating neutron stars--either radio pulsars or magnetars, which have the strongest known magnetic fields of any star.

But in those older maps, researchers were concerned that a significant amount of the gamma-ray emission might be coming from the sun's neighborhood or star formation at a few localized sources rather than from throughout the galaxy.