NLTT 372          was originally part of the reference field of the system G 131-26AB. It is within the error circle of the ROSAT X-ray source we attribute to G 131-26AB, and may either contribute or be the source of those X-rays. It is more luminous than a single star of its photometric colors, and is likely to be a binary.
GJ 2006       AB  appear to be {beta} Pictoris members, based on kinematics, gravity, and their positions relative to the {beta} Pictoris isochrone. A spectrum of GJ 2006A was obtained with Very Large Telescope (VLT) instrumentation (L. Malo et al., in preparation) and the radial velocity was determined to be +8.90km/s with vsini of 6km/s, in excellent agreement with that of a predicted {beta} Pictoris member.
SCR 0103-5515 ABC was resolved as a close triple by Delorme et al. (2013A&A...553L...5D) composed of two M dwarfs, A and B, and a more spatially distant brown dwarf, C (see Table 10). Delorme et al. (2013A&A...553L...5D) and the results from Bayesian Analysis for Nearby Young AssociatioNs (BANYAN) find it to be a match to Tucana-Horologium, but we find that its kinematics better match the Carina association, and because both associations are supposed to be the same age, we cannot distinguish between them with the other methods. When their photometry is deblended, both components lie above the {beta} Pictoris isochrone, implying that they are younger than {beta} Pic, even though Tucana-Horologium and Carina are both supposed to be older than {beta} Pic. The system is undoubtedly young, but more observations are needed to determine if it is a higher-order multiple in Tuc-Hor, or something entirely different.
GJ 2022       ABC is a hierarchical triple (see Table 10) composed of a wide (37.8'') companion (B) to a close (1.8'') nearly equal-luminosity pair (AC) with a delta magnitude of roughly {Delta}V=0.08 (Jao et al., 2003AJ....125..332J; Daemgen et al., 2007ApJ...654..558D). The B component is actually the least luminous, though to preserve the historical order of discovery, we continue to refer to it as "B." The AC component is bright in ROSAT All-Sky Survey (RASS; Voges et al. 1999, cat. IX/10, 2000, cat. IX/29); there is no corresponding detection of the B component. The A and C components are separated by 1.8'' (Figure 9). They are separable and (as they are much brighter than the B component) unsaturated on only 31 of the 66 images taken. Those 31 images were taken on 14 nights spanning 11.89yr and positions were obtained using special extra-sensitive (but less precise) SExtractor settings. A reduction of all three components yields (1) GJ 2022A: {pi}=40.91+/-5.64mas, {mu}=210.5+/-1.3mas/yr @ 126.5{deg}+/-0.71{deg}, (2) GJ 2022B: {pi}=42.12+/-3.60mas, {mu}=206.2+/-0.8mas/yr @ 127.4{deg}+/-0.46{deg}, (3) GJ 2022C: {pi}=46.96+/-5.31mas, {mu}=200.6+/-1.2mas/yr @ 126.8{deg}+/-0.71{deg}. This implies a weighted mean parallax of 43.05+/-2.63mas (23.2+/-1.4pc), which is consistent with our main reduction of B in Table 3 using 66 frames (38.80+/-2.13mas, 25.8+/-1.4pc) and with membership in the AB Dor association. Formally, we are using the parallax of the B component alone as our system parallax in Table 4 due to the lower precision of the results for all three components.
LHS 1302          is potentially a kinematic match for the ~30Myr old Columba association, but its gravity (Figure 5) and isochrones (Figure 4) suggest it is a field object.
LP 993-115        LP 993-115 (A)/LP 993-116AB (BC). We detect the astrometric orbital motion of the BC pair (Figure 10). Our attempt to fit an orbit did not converge, and the astrometry in Table 3 was calculated without compensating for orbital motion. This triple system appears to be composed of field stars, and only the BC components have X-ray emission.
LP 993-116    AB  LP 993-115 (A)/LP 993-116AB (BC). We detect the astrometric orbital motion of the BC pair (Figure 10). Our attempt to fit an orbit did not converge, and the astrometry in Table 3 was calculated without compensating for orbital motion. This triple system appears to be composed of field stars, and only the BC components have X-ray emission.
LP 476-207    ABC was observed by Hipparcos as HIP 23418; the resulting parallax was of poor quality due to erroneous coordinates in the input catalog (cat. I/239) and the resulting poor available astrometry. Our new result (24.6+/-1.3pc) is significantly closer and higher precision than the old (cat. I/239; 32.1+/-8.8pc) and revised (van Leeuwen 2007, cat. I/311; 33.2+/-10.5pc) Hipparcos values, but the system is still in {beta} Pic.
BD-21 1074    ABC is a known member of the {beta} Pic association (Torres et al., 2008hsf2.book..757T; Malo et al. 2013, cat. J/ApJ/762/88). The A component was not originally targeted for parallax measurement and was saturated in many early images; the parallax result in Table 3 is of lower precision. The BC component was observed by the HST FGS Interferometer on 2008 December 18, and resolved (Figure 11) in both axes, with details in Table 10. The measured position angle is discrepant with the current Washington Double Star catalog value (0.8'' @ 321{deg}) but matches the angle of the visible elongation of the BC point spread function from Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI) data, as seen in Figure 12. We see an astrometric binary signal in our astrometry, as shown in Figure 13.
L 449-1       AB  was identified as an active star by Scholz et al. (2005A&A...439.1127S). This system was on the Hubble Space Telescope (HST) Cycle 16B Fine Guidance Sensor (FGS) proposal, and was resolved into two stars on 2008 December 3 (Figure 14) with {Delta}F583W=0.95mag (see Table 10). The astronomic data displays what may be a very weak perturbation (Figure 15) due to orbital motion, but it is not convincing. By H-R diagram isochrones and gravity indices, this system is indistinguishable from main-sequence stars. The system's kinematics are a potential match for the Ursa Major moving group, which given the probable age of 500Myr (King et al., 2003AJ....125.1980K) again suggests that the components may be nearly zero-age main sequence (ZAMS).
LHS 1358          has kinematics consistent with the Hyades stream. Various authorities (e.g., Famaey et al., 2008A&A...483..453F) dispute the existence of the stream as a real kinematic entity; at only 15.3+/-0.5pc from the Sun, LHS 1358 is a minimum of 30pc (3 tidal radii) from the Hyades cluster center, and therefore the identification is not physical.
SCR 0613-2742 AB  is the lowest proper motion system (11.2+/-1.0mas/yr) thus far observed on Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI), with a transverse velocity of 1.6km/s. The system is a binary, observed on 2008 December 4 and resolved into two stars (Figure 16, Table 10) by Fine Guidance Sensor (FGS), and is also detected as a binary by our FEROS spectroscopy. We see orbital motion in the CTIOPI astrometric residuals of this star (Figure 17) and have removed that orbital motion (the orbit that was fit assumes a 4.67yr orbit starting at T0 of 2010.803 Julian Years, with photometric semimajor axis 0.54arcsec, inclination 89.9{deg}, eccentricity of 0.9999, a longitude of the ascending node of 201.3{deg}, and longitude of periastron of 90.3{deg}. While it removes the orbital bias from our astrometric data, we do not consider the orbit correct) from our astrometric results (Riedel et al., 2010AJ....140..897R), but we do not have data on a full orbit. Based on the FEROS spectroscopy, we see no Li 6708{AA} doublet absorption. This is expected for {beta} Pictoris members near the lithium depletion boundary (Yee & Jensen, 2010ApJ...711..303Y). The position and proper motion of SCR 0613-2742AB, near the convergent point of the {beta} Pic association, are extremely similar to those of 2MASS J06085283-2753583 (Cruz et al. 2003, cat. J/AJ/126/2421; Rice et al., 2010ApJ...715L.165R), a brown dwarf {beta} Pic member. The parallax of 2M0608 (32.0+/-3.6mas, 31.3+/-3.5pc; Faherty et al. 2012, cat. J/ApJ/752/56) is also very similar to SCR0613 (34.0+/-1.0mas, 29+/-0.9pc). The two systems are separated by 3529'' @ 78.6{deg}, which yields a minimum projected separation of 100kAU (~0.5pc). It is difficult to compare their proper motions--(+8.9,+10.7)+/-(3.5)mas/yr relative (2M0608) and (-13.1,-0.3)+/-(11.6,15.5)mas/yr absolute (SCR0613)--given the large uncertainties involved, save that each are marginally consistent with both zero and each other. Meanwhile, the binding energy, U_g_=(-GM_1_M_2_/r)=-1.28*10^33^J using the conservative estimates that the two components of SCR0613 have a combined mass of 0.5M{sun}, and 2M0608 is 0.015M{sun}. This binding energy is lower than any of the extremely wide systems studied in Caballero (2009A&A...507..251C), and it is probable that these stars are not gravitationally bound. It is possible that this was a bound system at one point (like AU/AT Mic=GJ 803/799AB, below), but is not any longer.
SCR 0757-7114     is overluminous by 2mag, plotting near the {beta} Pic isochrone on the H-R diagram in Figure 4, and has low surface gravity based on its KI measurement, but not NaI. Surprisingly, it shows no other signs of youth or membership in any known association--in fact, it has no X-ray emission, and is the only star under consideration with H{alpha} in absorption. Thus, the star's elevation on the H-R diagram is most likely due to unresolved multiplicity.
L 34-26           is a potential kinematic match to the Ursa Major moving group, but its measured radial velocity (+0.9km/s, no error; Torres et al. 2006, cat. J/A+A/460/695) is most likely discrepant with the best-fit Ursa Major moving group radial velocity, +6.6km/s.
SCR 1012-3124 AB  is a close ~1'' binary (Figure 18 and Table 10). There are a few epochs where the B component (to the west of the A component) can be seen, but for the most part the two components are blended in our astrometric observations. Radial velocity measurements with the VLT-UT1 CRyogenic high-resolution infraRed Echelle Spectrograph (CRIRES) presented in L. Malo et al. (in preparation) confirm the star's multiplicity, and yield radial velocities of 14.69+/-0.53km/s and 14.43+/-0.75km/s, for A and B, respectively. The vsini measurements (A: 15.52+/-2.01km/s; B: 20.40+/-2.58km/s) are also indicative of youth, where Reiners et al. (2009ApJ...692..538R) considers vsini>20km/s the minimal condition for a "fast rotator." While it is outside the normal spatial bounds (Torres et al., 2008hsf2.book..757T) of the TW Hydra association (its R.A. is slightly lower than that of TWA 21, at 10^h^13^m^), its UVW kinematics are consistent with TW Hydra, as is its deblended isochrone position (Figure 4). Its gravity measurements (Figure 5) indicate it is extremely young.
TWA 8         AB  was listed by Jao et al. (2003AJ....125..332J) as RXJ1132-264AB and was not included in the TW Hydra analysis of Weinberger et al. (2013ApJ...762..118W); our information is consistent with their conclusions based on other members of TW Hydra in that analysis.
G 165-8       AB  appears to be between the ages of {beta} Pictoris and AB Doradus based on its gravity measurement and deblended H-R diagram positions. There are two highly discrepant radial velocities published for this system, +8+/-0.1km/s (Montes et al. 2001, cat. J/A+A/379/976) and -7.5+/-6.5km/s (Gizis et al. 2002, cat. J/AJ/123/3356). We would normally choose the former value due to its higher precision, but the kinematics derived using that value agree with no known association. Ignoring radial velocities altogether, we find best-fit matches to the Tucana-Horologium ({gamma}=0.58, best-fit radial velocity -6.2km/s), Carina ({gamma}=0.62, best-fit radial velocity -10.4km/s), and Columba ({gamma}=2.40, best-fit radial velocity -12.5km/s) associations, all with estimated ages of 30Myr. It seems likely that the Gizis et al. 2002 (cat. J/AJ/123/3356) radial velocity is accurate, and the uncertainty is accounting for orbital motion of the binary. Using the latter radial velocity, the best match is to Carina, though Bayesian Analysis for Nearby Young AssociatioNs (BANYAN) favors Columba. Unusually, this system is a northern hemisphere target well outside the published spatial boundaries of all three associations. This suggests that either there is a fourth 30Myr old association nearby, possibly containing two other northern hemisphere objects thought to be members of the 30Myr old Columba association: HR 8799 (Marois et al., 2008Sci...322.1348M; Baines et al. 2012, cat. J/ApJ/761/57) and {kappa} And (Carson et al., 2013ApJ...763L..32C), or that the existing assumptions about the boundaries of the known associations are incorrect.
SCR 1425-4113 AB  is a curious system. High-resolution ESPaDOnS spectra of this target show that it is a spectroscopic binary, and an extremely rapid rotator (vsini=95.0+/-8.1km/s), with a radial velocity of (-1.2+/-1.3km/s). Its lithium equivalent width was also measured at 595+/-20m{AA}, confirming its youth. The deblended magnitudes of both of its components place them above (though consistent with) the TW Hydra isochrone on an H-R diagram, and the gravity measurements (which should not be affected by multiplicity) place it at lower surface gravity than TWA 8AB and SCR 1012-3124AB (though still within the errors). Our kinematics find it to be a much better fit to {beta} Pictoris ({gamma}=0.59) than TW Hydra ({gamma}=6.46), but Bayesian Analysis for Nearby Young AssociatioNs (BANYAN) finds 75% probability of it being a TW Hydra member, compared with 24% probability that it is actually a {beta} Pictoris member. It is additionally outside the normal spatial boundaries of TW Hydra (being a full hour of R.A. "higher" than the highest current member, TWA 18, at 13^h^21^m^ R.A.). We nevertheless consider it as a potential TW Hydra member because with its extremely high luminosity, low surface gravity, and position relatively close to TW Hydra, it either must be an outlying member of TW Hydra or something equally young.
SCR 2010-2801 AB  was found to be a binary by Bergfors et al. (2010A&A...520A..54B). The system was observed with Hubble Space Telescope-Fine Guidance Sensor (HST-FGS) on 2009 April 26, as seen in Figure 19. The resulting separation agrees with the separation published in Bergfors et al. (2010A&A...520A..54B).
LEHPM2-0783       has X-ray emission and the strongest H{alpha} emission in the sample, despite its cool temperatures. It lies above the main sequence, though it is too red to be seen on Figure 4. It is, however, not a potential kinematic match to any known young association. It may be younger than a typical field star, but we have no reason to suspect it is anything more than an unresolved binary.
L 755-19          is kinematically consistent with both Castor and Argus. It lies within the upper main-sequence locus, above the AB Doradus isochrone, which would be more consistent with the Argus association (younger than AB Dor) or a main-sequence binary than the Castor moving group (older than AB Dor). L 755-19 is a hotter star than AP Col (Riedel et al., 2011AJ....142..104R), and its surface gravity is comparable with either field stars or Argus-age objects. A radial velocity would go a long way toward determining the status of this star, given that the best-fit Argus radial velocity is -25.4km/s, and the best-fit Castor radial velocity is -9.3km/s, and a Castor/main-sequence assignment would imply it is a binary.
SCR 2033-2556     is consistent with being a member of {beta} Pictoris, but its high luminosity suggests it is an unresolved binary. Observations with ESPaDOnS (L. Malo et al., in preparation) suggest a lithium equivalent width of 510m{AA}, confirming the star's youth.
GJ 799        AB  GJ 803 (A)/GJ 799AB (BC) is one of the nearest young systems (see Table 10) to the Sun, and a prototypical member of the {beta} Pic association (Barrado y Navascues et al., 1999ApJ...520L.123B). AU Mic (unobserved by CTIOPI) is known to have a dust disk, and several authors note that the AU-AT Mic separation is very large (at least 0.23pc) and "must be very fragile and will soon be torn apart by third bodies" (Caballero, 2009A&A...507..251C). This system is a well-established member of the 10pc sample with parallaxes from Hipparcos and the Yale Parallax Catalog (van Altena et al. 1995, cat. I/238); our results agree with the published values. In our first epoch (2003 July 9) GJ 799 A and B were separated by 2.8'' @ 171{deg}; in our final epoch (2012 July 31, Figure 20) they were separated by 2.3'' @ 153{deg}.
GJ 1284       AB  is identified as a potential member of Columba by kinematic analysis; however, Torres et al. 2006 (cat. J/A+A/460/695) identified it as a spectroscopic binary, which implies it is a system of main-sequence stars, and the kinematic match is spurious.