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Session 70 - Searching for Other Planetary Systems.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center

[70.22] Discovery of the 20th Nearest Star

T. J. Henry (STScI), J. D. Kirkpatrick (JPL/Caltech), P. A. Ianna (U. Virginia), H. Jahreiss (Astronomisches Rechen-Institut)

As part of our systematic campaign to discover and characterize stars within 10 pc, we have found a star that ranks 20th among the Sun's nearest neighbors. This star, known as GJ 1061, has V = 13.0, K = 6.6, and lies only 3.7 pc away. GJ 1061 is a shocking reminder of how little we know of the universe even close to home.

The nearby star sample yields important information about the stellar population and mass budget of the Galaxy, as well as much of our knowledge about stellar luminosities, colors and masses. However, the current sample --- defined here to be all stars within 10 pc, currently 314 stars in 226 systems --- is woefully incomplete. We estimate that 130 systems are currently ``missing'' from the census, and have begun observing programs in both hemispheres to recover these missing stars. In a single observing run at CTIO we have found 17 additional stars to be within 10 pc, while in the north we have 7 more targets from previous observations. These two dozen stars result in an increase in the population of the nearest stars by 8%, with only a modicum of effort.

``Potential'' nearby stars are selected using preliminary photometric distance estimates and/or high proper motion. VRIJHK photometry is used to derive photometric distances accurate to 15--20%, and spectroscopy in the spectral range 6150--9350 Åverifies that a target is a nearby dwarf rather than a subdwarf or reddened giant merely mimicking the colors of a nearby dwarf. If the target has a derived photometric distance within 10 pc and is not eliminated in spectroscopic follow-up, it is advanced to the ``probable'' nearby category, and placed on the trigonometric parallax programs of U. Virginia and USNO.

The nearest stars are included by many brown dwarf, planetary, and SETI search programs in their observing lists. As our reconnaissance of the nearest stars continues, we will be able to provide researchers in these fields with the most comprehensive nearby star sample available.

Program listing for Wednesday