THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION,

By T. Dupuy, Michael C. Liu. 2012

473 citations recorded by the source corpus.

We present the first results from our high-precision infrared (IR) astrometry program at the Canada–France–Hawaii Telescope. We measure parallaxes for 83 ultracool dwarfs (spectral types M6–T9) in 49 systems, with a median uncertainty of 1.1 mas (2.3%) and as good as 0.7 mas (0.8%). We provide the first parallaxes for 48 objects in 29 systems, and for another 27 objects in 17 systems, we significantly improve upon published results, with a median (best) improvement of 1.7 times (5 times). Three systems show astrometric perturbations indicative of orbital motion; two are known binaries (2MASS J0518−2828AB and 2MASS J1404−3159AB) and one is spectrally peculiar (SDSS J0805+4812). In addition, we present here a large set of Keck adaptive optics imaging that more than triples the number of binaries with L6–T5 components that have both multi-band photometry and distances. Our data enable an unprecedented look at the photometric properties of brown dwarfs as they cool through the L/T transition. Going from ≈L8 to ≈T4.5, flux in the Y and J bands increases by ≈0.7 mag and ≈0.5 mag, respectively (the Y- and J-band “bumps”), while flux in the H, K, and L′ bands declines monotonically. This wavelength dependence is consistent with cloud clearing over a narrow range of temperature, since condensate opacity is expected to dominate at 1.0–1.3 μm. Interestingly, despite more than doubling the near-IR census of L/T transition objects, we find a conspicuous paucity of objects on the color–magnitude diagram just blueward of the late-L/early-T sequence. This “L/T gap” occurs at (J − H)MKO = 0.1–0.3 mag, (J − K)MKO = 0.0–0.4 mag, and implies that the last phases of cloud evolution occur rapidly. Finally, we provide a comprehensive update to the absolute magnitudes of ultracool dwarfs as a function of spectral type using a combined sample of 314 objects.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/542c726243a022b9922491180095fdb2f7b3d842

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In Astronomy and Astrophysics

1. Michael C. Liu
2. T. Dupuy
3. M. Marley
4. A. Burgasser
5. B. Bowler
6. K. Allers
7. Kelle Cruz
8. Jon Fortney

In Instrumentation

1. Michael C. Liu
2. T. Dupuy
3. A. Burgasser
4. M. Marley
5. K. Allers
6. Kelle Cruz
7. B. Bowler
8. K. Luhman

Citations in the corpus

• NEGLECTED CLOUDS IN T AND Y DWARF ATMOSPHERES (2012, methodology): “Color-Magnitude Diagrams In Figure 9, we plot the photometric colors in the nearinfrared of all brown dwarfs with measured parallaxes and apparentJ andK magnitude errors smaller than 0.2 magnitudes (Dupuy & Liu 2012; Faherty et al. 2012).”
• The Field Substellar Mass Function Based on the Full-sky 20 pc Census of 525 L, T, and Y Dwarfs (2020, unknown): “…et al. 2006, (62) Burgasser et al. 2010, (63) Kasper et al. 2007., (64) Pinfield et al. 2008, (65) Luhman et al. 2011, (66) Faherty et al. 2012, (67) Dupuy & Liu 2012, (68) Vrba et al. 2004, (69) Subasavage et al. 2009, (70) Marocco et al. 2010, (71) Burgasser et al. 2008a, (72) Gaia Collaboration…”
• DISCOVERY OF A BINARY BROWN DWARF AT 2 pc FROM THE SUN (2013, background): “In an unresolved binary containing unequal components, the orbital motion is reflected in movement of the photocenter, which can introduce errors into derived parallax and proper motion (e.g., Dupuy & Liu 2012).”
• THE GEMINI/NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF PLANETS AROUND YOUNG MOVING GROUP STARS (2013, unknown): “5 (Allers & Liu 2013; Dupuy & Liu 2012).”
• Individual Dynamical Masses of Ultracool Dwarfs (2017, methodology): “In this work we have added new flux ratios in CH4S and K bands for 2MASS J1404−3159AB that allow us to refine our analysis, and we find the same spectral types as we did in Dupuy & Liu (2012), L9± 1 – 19 – and T5.”
• FUNDAMENTAL PARAMETERS AND SPECTRAL ENERGY DISTRIBUTIONS OF YOUNG AND FIELD AGE OBJECTS WITH MASSES SPANNING THE STELLAR TO PLANETARY REGIME (2015, methodology): “…parallaxes for a diverse sample of late-M, L and T dwarfs (e.g., Dahn et al. 2002; Tinney et al. 2003; Vrba et al. 2004; Faherty et al. 2009; Dupuy & Liu 2012; Marocco et al. 2013; Dieterich et al. 2014; Tinney et al. 2014) is crucial to providing precise Lbol measurements across the entire…”
• PLANETS AROUND LOW-MASS STARS (PALMS). IV. THE OUTER ARCHITECTURE OF M DWARF PLANETARY SYSTEMS (2014, methodology): “The H-band photometric distance to the companion is 27 ± 2 pc using the absolute magnitude-spectral type relation from Dupuy & Liu (2012).”
• THE HAWAII INFRARED PARALLAX PROGRAM. II. YOUNG ULTRACOOL FIELD DWARFS (2016, methodology): “As described in Dupuy & Liu (2012), our measurements are as good as have ever been achieved in the near-IR, producing parallaxes with typical uncertainties of 1.3 mas and as good as 0.7 mas, but for objects ≈2–3 mags fainter than have been measured by previous parallax programs.”
• HST SPECTRAL MAPPING OF L/T TRANSITION BROWN DWARFS REVEALS CLOUD THICKNESS VARIATIONS (2013, methodology): “Here we plotted a full sequence of L/T dwarfs using the parallax and near-infrared photometric database by Dupuy & Liu (2012).”
• THE EXTREMELY RED, YOUNG L DWARF PSO J318.5338−22.8603: A FREE-FLOATING PLANETARY-MASS ANALOG TO DIRECTLY IMAGED YOUNG GAS-GIANT PLANETS (2013, methodology): “Our methods are described in Dupuy & Liu (2012).”
• BANYAN. II. VERY LOW MASS AND SUBSTELLAR CANDIDATE MEMBERS TO NEARBY, YOUNG KINEMATIC GROUPS WITH PREVIOUSLY KNOWN SIGNS OF YOUTH (2013, methodology): “This object has an L6 co-moving companion displaying signs of youth for which Dupuy & Liu (2012) measured a distance of 62 ± 27 pc, which further weakens the hypothesis that this object is a candidate member to any NYA considered here.”