This list is accurate as of 01 January 2012.
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To be a member of the RECONS 10 Parsec Sample, a star (and any
attending companions) must have a trigonometric parallax of 100
milliarcseconds or more, and an error in that parallax of less than 10
milliarcseconds. This parallax corresponds to a distance of 10
parsecs, or 32.6 light years. The error requirement means that the
distance to every member of this sample is known to 10% or better.
In the following counts, the Sun is included, and the eight planets in
our Solar System are noted as +8 in the planet counts. Brown dwarfs
as well as planets orbiting other stars are also included in the
counts. Additions to the census continue. Occasional deletions also
occur, when reported objects do not stand up to further scrutiny.
Only results published in refereed journals are included in the
counts.
As of January 1, 2000, the RECONS Census of objects known within 10
parsecs included 293 objects in 213 systems. (+8 planets in our Solar
System)
As of January 1, 2010, the RECONS Census of objects known within 10
parsecs included 366 objects in 256 systems. (+8 planets in our Solar
System)
As of January 1, 2012, the RECONS Census of objects known within 10
parsecs included 376 objects in 259 systems. (+8 planets in our Solar
System)
RECONS added 31 of the 46 new systems to the census between 2000 and
2010. An additional system --- GJ 1061 as the 20th nearest --- was
added in 1997, bringing the RECONS total to 32.
Note that the multiplicity rate, or the probability that a given
system has more than one component, is only 29%. The low rate is
because M-type dwarfs (also called red dwarfs) dominate the solar
neighborhood (a full 73% of the stellar sample, i.e. not L/T/P
objects, are M-type dwarfs), and do not have companions as often as
their more massive stellar cousins. In the table below, companions
include stars and brown dwarfs, whereas planets are listed separately.
Planets are not considered in the numbers of singles, doubles, etc.,
i.e. the Sun is counted as a single system.
The breakdown of objects can be summarized as:
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2000.0 2010.0 2012.0 notes
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total objects 293(+8) 366(+8) 376(+8) 28% increase since 2000
systems 213 256 259 22% increase since 2000
companions 78(+8) 97(+8) 98(+8) 26% increase since 2000 (stars+L+T)
planets 2(+8) 13(+8) 19(+8) exoplanets (+Solar System planets)
singles 153 183 185 planets not considered
doubles 46 54 55
triples 11 15 15
quadruples 2 3 3
quintuples 1 1 1
WDs 18 20 20 white dwarfs
Os 0 0 0
Bs 0 0 0
As 4 4 4
Fs 6 6 6
Gs 20 20 20
Ks 44 44 44
Ms 198 246 248 25% increase since 2000
Ls 0 4 5
Ts 1 9 10
Ps 2(+8) 13(+8) 19(+8) 1 planet around GJ 144 (epsilon Eri)
1 planet around GJ 176
1 planet around GJ 442A
3 planets around GJ 506 (61 Vir)
4 planets around GJ 581
1 planet around GJ 674
1 planet around GJ 785
1 planet around GJ 832
1 planet around GJ 849 (Wolf 1329)
4 planets around GJ 876 (Ross 780)
1 planet around GJ 881 (Fomalhaut)
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Note: Planet counts are as reported, although not all may be confirmed. At this
time, we do not include planets "f" and "g" in the GJ 581 system.
For questions or comments, please contact Dr. Todd J. Henry at thenry@chara.gsu.edu