We present the design, construction, and performance of SpeX, a medium-resolution 0.8-5.5 mm cryogenic spectrograph and imager, now in operation at the 3.0 m NASA Infrared Telescope Facility (IRTF) on Mauna Kea. The design uses prism cross-dispersers and gratings to provide resolving powers up to R ∼ 2000 simultaneously across 0.8-2.4, 1.9-4.2, or 2.4-5.5 mm, with a 15Љ long slit. A high-throughput low-resolution prism mode is also provided for faint-object and occultation spectroscopy. Single-order 60Љ long-slit R ∼ 200 modes with resolving powers up to are available for extended objects. The spectrograph employs an R ∼ 2000 Aladdin 3 InSb array and uses narrow slits and a spatial scale of 0Љ .15 pixel for optimum sensitivity Ϫ1 1024 # 1024 on point sources. An autonomous infrared slit viewer is used for object acquisition, infrared guiding, and scientific imaging in the wavelength range 0.8-5.5 mm. The imager employs an Aladdin 2 InSb array that 512 # 512 covers a field of view at 0Љ .12 pixel . SpeX was successfully commissioned on IRTF during 2000 Ϫ1 60 # 60 May, June, and July. Astronomical observations are presented to illustrate performance.

We report results of a direct imaging survey for giant planets around 80 members of the β Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ∆H=13.9 mag at 1" in combined CH 4 narrowband ADI+SDI 0 mode and median contrasts of ∆H=15.1 mag at 2" in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with NICI all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI campaign followup. Four comoving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36±6 M Jup , 16.4±1.0 AU, Biller et al. 2010) , CD -35 2722B (31±8 M Jup , 67±4 AU, Wahhaj et al. 2011), HD 12894B (0.46±0.08 M ⊙ , 15.7±1.0 AU), and BD+07 1919C (0.20±0.03 M ⊙ , 12.5±1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the β Pic moving group observed with high contrast adaptive optics imaging as part of the Gemini NICI Planet-Finding Campaign. The companion Myr for the system, we estimate a mass of 36±6 M Jup based on the Lyon/DUSTY evolutionary models. PZ Tel B is one of few young substellar companions directly imaged at orbital separations similar to those of giant planets in our own solar system. Additionally, the primary star PZ Tel A shows a 70 µm emission excess, evidence for a significant quantity of circumstellar dust that has not been disrupted by the orbital motion of the companion.Subject headings: brown dwarfs -planetary systems -stars: pre-main sequence

We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.5 ′′ and 14.1 mag at 1" separation. Follow-up observations of the 66 candidates with projected separation < 500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known β Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a ≥5M Jup planet beyond 80 AU, and <21% of debris disk stars have a ≥3M Jup planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly-imaged planets as d 2 N/dMda ∝ m α a β , where m is planet mass and a is orbital semimajor axis (with a maximum value of a max ). We find that β < −0.8 and/or α > 1.7. Likewise, we find that β < −0.8 and/or a max < 200 AU. For the case where the planet frequency rises sharply with mass (α > 1.7), this occurs because all the planets detected to date have masses above 5M Jup , but planets of lower mass could easily have been detected by our search. If we ignore the β Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a ≥3M Jup planet beyond 10 AU, and β < −0.8 and/or α < −1.5. Likewise, β < −0.8 and/or a max < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet formation; our non-detections at large separations show that planets with orbital separation > 40 AU and planet masses > 3 M Jup do not carve the central holes in these disks.An interesting result of direct imaging searches so far is that many of the systems with exoplanet discoveries also have debris disks, i.e. β Pictoris, HR 8799 and Fomalhaut (Lagrange et al. 2009;Marois et al. 2008;Kalas et al. 2008). Even though the discovery rate for large-separation exoplanets in debris disk systems is low (<2%; this work), the discovery rate in non-debris disk systems is even lower. In addition, Wyatt et al. (2012) find that the RV-discovered systems with only Saturn-mass planets have a higher-than-expected debris disk fraction, 4 out of 6 (67% ) compared to 4 of 11 (36%) in the full sample of stars with RV planets (debris disk fraction in RV Jupiter-mass systems is constrained to <20%). The correlation between higher disk fraction and lower-mass planets suggests that the formation mechanism for Saturn-only systems results in large, stable debris disks which can produce dust for a l...

We present the discovery of a wide (67 AU) substellar companion to the nearby (21 pc) young solar-metallicity M1 dwarf CD−35 2722, a member of the ≈100 Myr AB Doradus association. Two epochs of astrometry from the NICI Planet-Finding Campaign confirm that CD−35 2722 B is physically associated with the primary star. Near-IR spectra indicate a spectral type of L4±1 with a moderately low surface gravity, making it one of the coolest young companions found to date. The absorption lines and near-IR continuum shape of CD−35 2722 B agree especially well the dusty field L4.5 dwarf 2MASS J22244381−0158521, while the near-IR colors and absolute magnitudes match those of the 5-Myr old L4 planetary-mass companion, 1RXS J160929.1−210524 b. Overall, CD−35 2722 B appears to be an intermediate-age benchmark for L-dwarfs, with a less peaked H-band continuum than the youngest objects and near-IR absorption lines comparable to field -3objects. We fit Ames-Dusty model atmospheres to the near-IR spectra and find T ef f =1700-1900 K and log(g) =4.5±0.5. The spectra also show that the radial velocities of components A and B agree to within ±10 km/s, further confirming their physical association. Using the age and bolometric luminosity of CD−35 2722 B, we derive a mass of 31±8 M Jup from the Lyon/Dusty evolutionary models. Altogether, young late-M to mid-L type companions appear to be overluminous for their near-IR spectral type compared to field objects, in contrast to the underluminosity of young late-L and early-T dwarfs. 15M J 25M J 39M J 63M J 7M J 11M J 15M J 22M J 31M J 44M J 6M J 10M J 16M J 26M J 41M J 66M J