IRCS: infrared camera and spectrograph for the Subaru Telescope

Kobayashi, Naoto; Tokunaga, A. T.; Terada, Hiroshi; Goto, Miwa; Weber, Mark; Potter, Robert D.; Onaka, Peter M.; Ching, Gregory K.; Young, Tony T.; Fletcher, Kent; Neil, Douglas M.; Robertson, Louis; Cook, Daniel; Imanishi, Masatoshi; Warren, David W.

doi:10.1117/12.395423

Cited by 229 publications

(49 citation statements)

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“…Cushing et al (2005) obtained high-resolution (λ/Δλ ≈ 1200 or 2000), 0.9-2.4 μm spectra of these dwarfs with the SpeX instrument (Rayner et al 2003) at NASA's Infrared Telescope Facility. Additional medium resolution 2.9-4.1 μm spectra with SpeX (λ/Δλ ≈ 940) and with the Infrared Camera and Spectrograph (IRCS) on the 8.2 m Subaru Telescope (λ/Δλ ≈ 425 or 210; Kobayashi et al 2000) were obtained as well. Cushing et al (2006) then obtained lowresolution (λ/Δλ ≈ 90), 5.5-38.0 μm spectra of the seven dwarfs using Spitzer's Infrared Spectrograph (IRS; Houck et al 2004) in the same configuration used for our observational sample (Section 3.1).…”

Section: Study Aims and Samplementioning

confidence: 99%

THE 0.8-14.5 μm SPECTRA OF MID-L TO MID-T DWARFS: DIAGNOSTICS OF EFFECTIVE TEMPERATURE, GRAIN SEDIMENTATION, GAS TRANSPORT, AND SURFACE GRAVITY

Stephens

Leggett

Cushing

et al. 2009

ApJ

356

387

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We present new 5.2-14.5 μm low-resolution spectra of 14 mid-L to mid-T dwarfs. We also present new 3.0-4.1 μm spectra for five of these dwarfs. These data are supplemented by existing red and near-infrared spectra (∼0.6-2.5 μm), as well as red through mid-infrared spectroscopy of seven other L and T dwarfs presented by Cushing et al. We compare these spectra to those generated from the model atmospheres of Saumon & Marley. The models reproduce the observed spectra well, except in the case of one very red L3.5 dwarf, 2MASS J22244381−0158521. The broad wavelength coverage allows us to constrain almost independently the four parameters used to describe these photospheres in our models: effective temperature (T eff ), surface gravity, grain sedimentation efficiency (f sed ), and vertical gas transport efficiency (K zz ). The CH 4 bands centered at 2.2, 3.3, and 7.65 μm and the CO band at 2.3 μm are sensitive to K zz , and indicates that chemical mixing is important in all L and T dwarf atmospheres. The sample of L3.5 to T5.5 dwarfs spans the range 1800 K T eff 1000 K, with an L-T transition (spectral types L7 to T4) that lies between 1400 and 1100 K for dwarfs with typical near-infrared colors; bluer and redder dwarfs can be 100 K warmer or cooler, respectively, when using infrared spectral types. When using optical spectral types, the bluer dwarfs have more typical T eff values as they tend to have earlier optical spectral types. In this model analysis, f sed increases rapidly between types T0 and T4, indicating that increased sedimentation can explain the rapid disappearance of clouds at this stage of brown dwarf evolution. There is a suggestion that the transition to dust-free atmospheres happens at lower temperatures for lower gravity dwarfs.

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Section: Study Aims and Samplementioning

confidence: 99%

THE 0.8-14.5 μm SPECTRA OF MID-L TO MID-T DWARFS: DIAGNOSTICS OF EFFECTIVE TEMPERATURE, GRAIN SEDIMENTATION, GAS TRANSPORT, AND SURFACE GRAVITY

Stephens

Leggett

Cushing

et al. 2009

ApJ

356

387

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“…We first imaged 2MASS 0122-2439 with the Infrared Camera and Spectrograph (IRCS; Kobayashi et al 2000;Tokunaga et al 1998) combined with the AO188 adaptive optics system (Hayano et al 2010) at the Subaru Telescope on UT 2012 October 12. Natural guide star (NGS) AO was used with 2MASS 0122-2439 A (R = 13.2 mag) acting as the wavefront reference.…”

Section: Subaru/ircs Adaptive Optics Imagingmentioning

confidence: 99%

Planets Around Low-Mass Stars. Iii. A Young Dusty L Dwarf Companion at the Deuterium-Burning Limit,

Bowler

Liu²,

Shkolnik

et al. 2013

ApJ

129

145

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We report the discovery of an L-type companion to the young M3.5V star 2MASS J01225093-2439505 at a projected separation of 1. 45 (≈52 AU) as part of our adaptive optics imaging search for extrasolar giant planets around young low-mass stars. 2MASS 0122-2439 B has very red near-infrared colors similar to the HR 8799 planets and the reddest known young/dusty L dwarfs in the field. Moderate-resolution (R ≈ 3800) 1.5-2.4 μm spectroscopy reveals a near-infrared spectral type of L4-L6 and an angular H-band shape, confirming its cool temperature and young age. The kinematics of 2MASS 0122-2439 AB are marginally consistent with members of the ∼120 Myr AB Dor young moving group based on the photometric distance to the primary (36 ± 4 pc) and our radial velocity measurement of 2MASS 0122-2439 A from Keck/HIRES. We adopt the AB Dor group age for the system, but the high energy emission, lack of Li i λ6707 absorption, and spectral shape of 2MASS 0122-2439 B suggest a range of ∼10-120 Myr is possible. The age and luminosity of 2MASS 0122-2439 B fall in a strip where "hot-start" evolutionary model mass tracks overlap as a result of deuterium burning. Several known substellar companions also fall in this region (2MASS J0103-5515 ABb, AB Pic b, κ And b, G196-3 B, SDSS 2249+0044 B, LP 261-75 B, HD 203030 B, and HN Peg B), but their dual-valued mass predictions have largely been unrecognized. The implied mass of 2MASS 0122-2439 B is ≈12-13 M Jup or ≈22-27 M Jup if it is an AB Dor member, or possibly as low as 11 M Jup if the wider age range is adopted. Evolutionary models predict an effective temperature for 2MASS 0122-2439 B that corresponds to spectral types near the L/T transition (≈1300-1500 K) for field objects. However, we find a mid-L near-infrared spectral type, indicating that 2MASS 0122-2439 B represents another case of photospheric dust being retained to cooler temperatures at low surface gravities, as seen in the spectra of young (8-30 Myr) planetary companions. Altogether, the low mass, low temperature, and red colors of 2MASS 0122-2439 B make it a bridge between warm planets like β Pic b and cool, very dusty ones like HR 8799 bcde.

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“…The Infrared Camera and Spectrograph (IRCS; Tokunaga et al 1998;Kobayashi et al 2000) was used in its lowresolution spectrograph mode. The IRCS was equipped with an Aladdin-III 1024 × 1024 InSb array at the Infrared Nasmyth focus (Terada et al 2004).…”

Section: Observationsmentioning

confidence: 99%

High-Albedo C-Complex Asteroids in the Outer Main Belt: The Near-Infrared Spectra

Kasuga

Usui

Ootsubo

et al. 2013

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Primitive, outer-belt asteroids are generally of low albedo, reflecting carbonaceous compositions like those of CI and CM meteorites. However, a few outer-belt asteroids having high albedos are known, suggesting the presence of unusually reflective surface minerals or, conceivably, even exposed water ice. Here, we present near-infrared (1.1-2.5 μm) spectra of four outer-belt C-complex asteroids with albedos 0.1. We find no absorption features characteristic of water ice (near 1.5 and 2.0 μm) in the objects. Intimate mixture models set limits to the water ice by weight 2%. Asteroids (723) Hammonia and (936) Kunigunde are featureless and have (60%-95%) amorphous Mg pyroxenes that might explain the high albedos. Asteroid (1276) Ucclia also shows a featureless reflection spectrum with (50%-60%) amorphous Mg pyroxenes. Asteroid (1576) Fabiola shows a possible weak, broad absorption band (1.5-2.1 μm). The feature can be reproduced by (80%) amorphous Mg pyroxenes or orthopyroxene (crystalline silicate), either of which is likely to cause its high albedo. We discuss the origin of high-albedo components in primitive asteroids.

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IRCS: infrared camera and spectrograph for the Subaru Telescope

Cited by 229 publications

References 0 publications

THE 0.8-14.5 μm SPECTRA OF MID-L TO MID-T DWARFS: DIAGNOSTICS OF EFFECTIVE TEMPERATURE, GRAIN SEDIMENTATION, GAS TRANSPORT, AND SURFACE GRAVITY

THE 0.8-14.5 μm SPECTRA OF MID-L TO MID-T DWARFS: DIAGNOSTICS OF EFFECTIVE TEMPERATURE, GRAIN SEDIMENTATION, GAS TRANSPORT, AND SURFACE GRAVITY

Planets Around Low-Mass Stars. Iii. A Young Dusty L Dwarf Companion at the Deuterium-Burning Limit,

High-Albedo C-Complex Asteroids in the Outer Main Belt: The Near-Infrared Spectra

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