The Vela planet was part of a haul of more than 50 new exoplanets — as planets around other stars are called — discussed in a news conference on Monday hosted by the European Southern Observatory. They are the newest fruits of an eight-year observing program by astronomers based at the University of Geneva and led by Stephane Udry and Michel Mayor, working from a telescope at the European Southern Observatory in Chile. About 16 of them are so-called super-Earths, with masses less than 10 times the Earth, further encouraging astronomers that they are on the verge of finding planets like ours. A pair of papers — one with Dr. Mayor as lead author and the other with Francesco Pepe, also of Geneva, as lead author — have been submitted to Astronomy and Astrophysics, describing the planets.

The Geneva astronomers used a sensitive spectrograph known as Harps (an acronym for High Accuracy Radial velocity Planet Searcher) to detect wobble in the stars’ motions as planets swung around them. The wobble technique, however, only reveals the masses of exoplanets. Without further information like the size — which NASA’s Kepler satellite, also in the exoplanet business, measures by seeing the shadows of planets as they cross in front of their stars — or the composition, the astronomers cannot say for sure whether the Vela planet is made of rock, steam, iron, diamonds or something else. Nor can they tell what, if any, atmosphere it has. Kepler will be of no help because its gaze is fixed on a different swath of sky.

The star that the Vela planet circles is known as HD 85512, or Gliese 370, after Wilhelm Gliese, a German astronomer. The star is orange, about two-thirds as massive and about an eighth as luminous as our Sun.

A study led by Dr. Kaltenegger, Dr. Pepe and Dr. Udry concluded that HD 85512b was potentially habitable if it had more than a 50 percent cloud cover.

Dimitar Sasselov of the Center for Astrophysics, who has followed this work but is not part of the team, said that Dr. Kaltenegger and her colleagues made reasonable assumptions. He called the result “very solid” and “a major step in the right direction.”