L′ and M′ Photometry of Ultracool Dwarfs

By D. Golimowski, S. Leggett, M. Marley, Xiaohui Fan, T. Geballe, G. Knapp, F. Vrba, A. Henden, C. Luginbuhl, H. Guetter and 9 more. 2004

409 citations recorded by the source corpus.

We have compiled L′ (3.4–4.1 μm) and M′ (4.6–4.8 μm) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory filter set. This compilation includes new L′ measurements of eight L dwarfs and 13 T dwarfs and new M′ measurements of seven L dwarfs, five T dwarfs, and the M1 dwarf Gl 229A. These new data increase by factors of 0.6 and 1.6, respectively, the numbers of ultracool dwarfs (Teff ≲ 2400 K) for which L′ and M′ measurements have been reported. We compute Lbol, BCK, and Teff for 42 dwarfs whose flux-calibrated JHK spectra, L′ photometry, and trigonometric parallaxes are available, and we estimate these quantities for nine other dwarfs whose parallaxes and flux-calibrated spectra have been obtained. BCK is a well-behaved function of near-infrared spectral type with a dispersion of ∼0.1 mag for types M6–T5; it is significantly more scattered for types T5–T9. Teff declines steeply and monotonically for types M6–L7 and T4–T9, but it is nearly constant at ∼1450 K for types L7–T4 with assumed ages of ∼3 Gyr. This constant Teff is evidenced by nearly unchanging values of L′–M′ between types L6 and T3. It also supports recent models that attribute the changing near-infrared luminosities and spectral features across the L-T transition to the rapid migration, disruption, and/or thinning of condensate clouds over a narrow range of Teff. The L′ and M′ luminosities of early-T dwarfs do not exhibit the pronounced humps or inflections previously noted in the I through K bands, but insufficient data exist for types L6–T5 to assert that ML′ and MM′ are strictly monotonic within this range of types. We compare the observed K, L′, and M′ luminosities of L and T dwarfs in our sample with those predicted by precipitating-cloud and cloud-free models for varying surface gravities and sedimentation efficiencies. The models indicate that the L3–T4.5 dwarfs generally have higher gravities (log g = 5.0–5.5) than the T6–T9 dwarfs (log g = 4.5–5.0). The predicted M′ luminosities of late-T dwarfs are 1.5–2.5 times larger than those derived empirically for the late-T dwarfs in our sample. This discrepancy is attributed to absorption at 4.5–4.9 μm by CO, which is not expected under the condition of thermochemical equilibrium assumed in the models. Our photometry and bolometric calculations indicate that the L3 dwarf Kelu-1 and the T0 dwarf SDSS J042348.57-041403.5 are probable binary systems. We compute log (Lbol/L⊙) = -5.73 ± 0.05 and Teff = 600–750 K for the T9 dwarf 2MASSI J0415195-093506, which supplants Gl 570D as the least luminous and coolest brown dwarf presently known.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/e88e77151d222523021653635b6baadde099357d

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In Astronomy and Astrophysics

1. Michael C. Liu
2. A. Burgasser
3. K. Luhman
4. M. Marley
5. T. Dupuy
6. J. D. Kirkpatrick
7. Kelle Cruz
8. Eric Mamajek

In Instrumentation

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

Citations in the corpus

• ON THE STELLAR POPULATIONS AND EVOLUTION OF STAR-FORMING GALAXIES AT 6.3 < z ⩽ 8.6 (2009, background): “Figure 3 shows the synthesized colors of brown–dwarf stars (us- ing spectra of brown dwarfs from S. Leggett6, with the data from Golimowski et al. (2004), Knapp et al. (2004) and Chiu et al. (2006)).”
• A VOLUME-LIMITED SAMPLE OF 63 M7–M9.5 DWARFS. II. ACTIVITY, MAGNETISM, AND THE FADE OF THE ROTATION-DOMINATED DYNAMO (2009, methodology): “To find the temperature of our targets, we used the spectral types and calculated Teff according to the conversion given in Golimowski et al. (2004).”
• Binaries and the L Dwarf/T Dwarf Transition (2006, methodology): “Nevertheless, Liu et al. (2006) hypothesized that a substantial fraction of L7–T5 dwarfs with parallax distance measurements—10 of 15 sources (0:66þ0:12 0:17)—are either resolved or unresolved binaries, due to their outlying position on the TeA/spectral type relation of Golimowski et al. (2004).”
• M dwarfs: effective temperatures, radii and metallicities (2008, methodology): “Our technique returns Teff = 2450 K, cooler then both Leggett et al. (2000) (2600 K) and Golimowski et al. (2004) (2725 K).”
• Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs (2008, methodology): “To find the temperature of our targets, we used the spectral types and calculated Teff according to the conversion given in Golimowski et al. (2004).”
• A Unified Near-Infrared Spectral Classification Scheme for T Dwarfs (2005, background): “The depletion of dust from cool brown dwarf photospheres is now believed to play a greater role in the spectral transition between L and T dwarfs than Teff (Ackerman & Marley 2001; Burgasser et al. 2002c; Tsuji & Nakajima 2003), although the mechanism for this depletion remains under considerable de”
• Imaging Extrasolar Giant Planets (2016, methodology): “Contrasts measured in CH4S filters are converted to H-band using an empir- ical color-spectral type relationship based on synthetic colors of ultracool dwarfs from the SpeX Prism Library (Burgasser 2014) as well as the spectral type-effective temperature sequence from Golimowski et al. (2004a)5.”
• A STELLAR CENSUS OF THE TUCANA–HOROLOGIUM MOVING GROUP (2014, methodology): “We converted the model Teff values to spectral types using the dwarf temperature sequence of Schmidt-Kaler (1982) for ≤M0 stars and the dwarf sequence of Golimowski et al. (2004) for ≥M1 stars.”
• THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE): MISSION DESCRIPTION AND INITIAL ON-ORBIT PERFORMANCE (2010, background): “A fraction S of the 4.6 µm flux is then suppressed, following Golimowski et al. (2004), who found a suppression factor 1/(1 − S) = 1.5 to 2.5, implying S = 0.5 ± 0.1.”
• RADIUS-DEPENDENT ANGULAR MOMENTUM EVOLUTION IN LOW-MASS STARS. I (2011, methodology): “The Teff corresponding to each sub-type is determined from the MS spectral type–Teff calibrations of Kenyon & Hartmann (1995) and Golimowski et al. (2004); corresponding masses are then derived from the BCAH98 MS mass–Teff relationship.”
• Evidence for a co-moving sub-stellar companion of GQ Lup (2005, methodology): “…gravity are well constrained, the temperature Teff is only weakly constrained to ∼1600 to 2500 K (or 2050±450 K) from Gorlova et al. (2003) and references therein as well as Reid et al. (1999), Stephens et al. (2001), Burgasser et al. (2002), Nakajima et al. (2004), and Golimowski et al. (2004).”
• A SURVEY OF z ∼ 6 QUASARS IN THE SLOAN DIGITAL SKY SURVEY DEEP STRIPE. I. A FLUX-LIMITED SAMPLE AT zAB < 21 (2007, background): “The open circles in Figure 2 represent known L/T dwarfs from Golimowski et al. (2004), Knapp et al. (2004), and Chiu et al. (2006).”
• THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION, (2012, background): “…(26) Gelino et al. (2006); (27) Gelino et al. (2011); (28) Gizis & Reid (2000); (29) Gizis et al. (2003); (30) Golimowski & Schroeder (1998); (31) Golimowski et al. (2004b); (32) Greissl et al. (2007); (33) Kasper et al. (2007); (34) King et al. (2010); (35) Koerner et al. (1999); (36)…”
• THE HAWAII INFRARED PARALLAX PROGRAM. II. YOUNG ULTRACOOL FIELD DWARFS (2016, background): “For objects of spectral type L (Teff ≈ 1300−2300 K; Golimowski et al. 2004; Stephens et al. 2009), a field object of typical age (≈1–5 Gyr) has a mass of ≈40–80 MJup according to evolutionary models (Chabrier et al. 2000; Saumon & Marley 2008).”
• PLANETS AROUND LOW-MASS STARS (PALMS). IV. THE OUTER ARCHITECTURE OF M DWARF PLANETARY SYSTEMS (2014, background): “L ′ color of 0.2 ± 0.1 mag for M2 dwarfs from Golimowski et al. (2004), we derive a KMKO–”
• A giant planet candidate near a young brown dwarf - Direct VLT/NACO observations using IR wavefront sensing (2004, methodology): “By comparison of the GPCC photometry with the infrared colors of field late-M, L and T dwarfs obtained by Leggett et al. (2001, 2002), Stephens et al. (2001), Golimowski et al. (2004) and Knapp et al. (2004), we obtain a spectral type L5−L9.”
• A PATCHY CLOUD MODEL FOR THE L TO T DWARF TRANSITION (2010, background): “However, 1200K is slightly cooler than the observed Teff temperature of the transition of ∼ 1300K (Golimowski et al. 2004; Stephens et al. 2009) and if Teff falls appreciably across the transition the J band bump would be weakened (Fig.”