J/AJ/170/43 301 L & T-type brown dwarfs archival spectra (Turner+, 2025) ================================================================================ A survey of model fits to brown dwarf spectra through the L-T sequence. Turner S.K., Stephens D.C., Scoresby C.B., Miller J.A. =2025AJ....170...43T ================================================================================ ADC_Keywords: Spectroscopy; Optical; Infrared; Stars, brown dwarf; Stars, L-type; Stars, T-type Keywords: Brown dwarfs ; L dwarfs ; T dwarfs ; Near IR astronomy ; IR spectroscopy Abstract: We fit archival near-IR spectra of ~300 brown dwarfs with atmosphere models from the Sonora and Phoenix groups. Using the parameters of the best- fit models as estimates for the physical properties of the brown dwarfs in our sample, we have performed a survey of how brown dwarf atmospheres evolve with spectral type and temperature. We present the fit results and observed trends. We find that clouds have a more significant impact on near-IR spectra than disequilibrium chemistry, and that silicate clouds influence the near-IR spectrum through the late T types. We note where current atmosphere models are able to replicate the data and where the models and data conflict. We also categorize objects with similar spectral morphologies into families and discuss possible causes for their unique spectral traits. We identify two spectral families with morphologies that are likely indicative of binarity. Description: The archival spectra were downloaded from the SpeX Prism Library (SPL; Burgasser, 2014ASInC..11....7B). Only the most recent spectrum with the highest resolution was used for each object. This left 301 spectra of unique sources with spectral types between L0 and T8. These archival spectra were obtained by multiple groups and published in various papers from 2004 to 2010. The SPL spectra were all taken with the SpeX spectrograph at the 3.0m NASA IR Telescope Facility. The spectra are low resolution ({lambda}/{Delta}{lambda}~75-200) and span the near-IR from about 0.8 to 2.5um. H and Ks magnitudes from the Two Micron All-Sky Survey (2MASS, II/246) were used to flux calibrate each spectrum. We found published parallaxes for ~170 of our 301 sample objects on the open-source SIMPLE Database. An additional ~70 objects had published parallaxes listed on SIMBAD. For objects with multiple published parallaxes, the one with the smallest uncertainty was used. The majority of these parallaxes came from Gaia EDR3(I/350) or Best+2020 (J/AJ/159/257). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table9.dat 129 301 List of all 301 archival spectra used in this project -------------------------------------------------------------------------------- See also: I/350 : Gaia EDR3 (Gaia Collaboration, 2020) I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/AJ/123/3409 : SDSS M, L, and T dwarfs (Hawley+, 2002) J/AJ/126/2487 : T dwarfs in the southern hemisphere (Burgasser+, 2003) J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003) J/AJ/127/2856 : Brown dwarfs in the 2MASS Survey (Burgasser+, 2004) J/AJ/127/3553 : JHK phot. and spectroscopy for L and T dwarfs (Knapp+, 2004) J/ApJ/637/1067 : Near-IR spectral class. of T dwarfs (Burgasser+, 2006) J/AJ/131/2722 : New L and T dwarfs from the SDSS (Chiu+, 2006) J/PASP/118/659 : RI photometry of 2MASS late M and L dwarfs (Liebert+, 2006) J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007) J/AJ/134/1162 : 11 new T dwarfs in 2MASS (Looper+, 2007) J/ApJ/689/1295 : Li test implications for brown dwarfs (Kirkpatrick+, 2008) J/ApJ/676/1281 : L and T dwarfs in 2MASS/SDSS (Metchev+, 2008) J/MNRAS/383/831 : New DENIS nearby L and late-M dwarfs (Phan-Bao+, 2008) J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008) J/A+A/497/619 : New ultra-cool dwarfs from SDSS and 2MASS (Zhang+, 2009) J/ApJ/710/1142 : SpeX spectro. of low mass binaries. I. (Burgasser+, 2010) J/ApJS/190/100 : NIR proper motion survey using 2MASS (Kirkpatrick+, 2010) J/AJ/139/1808 : Colors and kinematics of SDSS L dwarfs (Schmidt+, 2010) J/ApJS/201/19 : Hawaii Infrared Parallax Program. I. (Dupuy+, 2012) J/ApJ/752/56 : BDKP. III. Parallaxes for 70 ultracool dwarfs (Faherty+, 2012) J/ApJ/746/23 : Radio observations of ultracool dwarf stars (McLean+, 2012) J/MNRAS/428/2824 : Rapid optical variability in ultracool dwarfs (Koen, 2013) J/ApJ/794/143 : New SpeX Observations of M7-L6 Dwarfs (Bardalez+, 2014) J/AJ/147/34 : SpeX library of L-type dwarfs (Schneider+, 2014) J/ApJS/219/33 : BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015) J/MNRAS/449/3651 : L and T dwarfs from UKIDSS LAS (Marocco+, 2015) J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016) J/ApJ/833/96 : Hawaii IR parallax program. II. Ultracool dwarfs (Liu+, 2016) J/ApJS/231/15 : Astrometric monitor. of ultracool dwarf binaries (Dupuy+, 2017) J/AJ/155/34 : Analysis of the NIR spectra of neighboring L dwarfs (Cruz+, 2018) J/MNRAS/481/3548 : Parallaxes of Southern Extremely Cool objects (Smart+, 2018) J/ApJ/883/205 : Ultracool SpeXtroscopic surv. I. M7-L5 sample (Bardalez+, 2019) J/AJ/157/101 : Cloud Atlas: HST/WFC3 NIR spectral library (Manjavacas+, 2019) J/AJ/159/257 : Hawaii IR parallax prog. IV. L0-T8 BDs with UKIRT (Best+, 2020) J/AJ/160/63 : IR spectra of 5 brown dwarfs with Gemini North IRS (Miles+, 2020) J/AJ/161/42 : Volume-limited samp of cool dwarfs. I. L0-T8 dwarfs (Best+, 2021) J/ApJS/253/7 : Full-sky census of brown dwarfs within 20pc (Kirkpatrick+, 2021) J/MNRAS/513/5701 : Silicate clouds in ultracool dwarfs (Suarez+, 2022) J/ApJ/943/L16 : Keck/NIRES sp. of CWISE J050626.96+073842.4 (Schneider+, 2023) http://doi.org/10.5281/zenodo.15314197 : Zenodo repository from this work Byte-by-byte Description of file: table9.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 28 A28 --- Name Object name 30- 52 A23 --- OName Alternate name 54- 66 A13 --- OType Optical spectral type (1) 68- 84 A17 --- IRType Near-IR spectral type (1) 86- 91 F6.3 mag Jmag [12.4/18.3] 2MASS J Vega magnitude 93- 98 F6.3 mag Hmag [11.5/16.7] 2MASS H Vega magnitude 100- 105 F6.3 mag Ksmag [11.0/17.1] 2MASS Ks Vega magnitude 107- 117 F11.7 --- plx [13.5/205.5]? Parallax, SIMPLE Database (see references) 119- 129 A11 --- Sources Sources (2) -------------------------------------------------------------------------------- Note (1): A single colon indicates an uncertainty of 1.5 spectral types or less, while a double colon indicates an uncertainty greater than 1.5 spectral types. Note (2): References as follows: 1 = Albert+2011 (2011AJ....141..203A) 2 = Allers+2013 (2013ApJ...772...79A) 3 = Bardalez Gagliuffi+2014 (J/ApJ/794/143) 4 = Best+2021 (J/AJ/161/42) 5 = Best+2021 (J/AJ/161/42) 6 = Burgasser+2006 (2006AJ....131.1007B) 7 = Burgasser+2003b (J/AJ/126/2487) 8 = Burgasser+2003a (2003ApJ...594..510B) 9 = Burgasser+2006 (J/ApJ/637/1067) 10 = Burgasser+2007 (2007ApJ...658..557B) 11 = Burgasser+2008b (2008ApJ...674..451B) 12 = Burgasser+2009 (2009AJ....138.1563B) 13 = Burgasser+2010 (J/ApJ/710/1142) 14 = Burgasser+2004 (J/AJ/127/2856) 15 = Burgasser+2008a (2008ApJ...681..579B) 16 = Burgasser+2011 (2011AJ....141...70B) 17 = Burgasser+2007 (2007ApJ...659..655B) 18 = Chiu+2006 (J/AJ/131/2722) 19 = Cruz+2004 (2004ApJ...604L..61C) 20 = Cruz+2003 (J/AJ/126/2421) 21 = Cruz+2007 (J/AJ/133/439) 22 = Cruz+2009 (2009AJ....137.3345C) 23 = Cruz+2018 (J/AJ/155/34) 24 = Cushing+2005 (2005ApJ...623.1115C) 25 = Dahn+2002 (2002AJ....124.1170D) 26 = Dupuy+2012 (J/ApJS/201/19) 27 = Dupuy+2017 (J/ApJS/231/15) 28 = Faherty+2010 (2010AJ....139..176F) 29 = Faherty+2012 (J/ApJ/752/56) 30 = Faherty+2013 (2013AJ....145....2F) 31 = Faherty+2016 (J/ApJS/225/10) 32 = Fan+2000 (2000AJ....119..928F) 33 = Gagne+2015 (J/ApJS/219/33) 34 = Gaia Collaboration+2016 (I/337) = Gaia Collaboration+2018 (I/345) 35 = Brown+2021 (2021A&A...650C...3G) 36 = Gauza+2019 (2019MNRAS.487.1149G) 37 = Geballe+2002 (2002ApJ...564..466G) 38 = Gelino+2010 (2010AJ....140..110G) 39 = Gizis+2000 (2000AJ....120.1085G) 40 = Gizis+2001 (2001AJ....121.2185G) 41 = Gizis+2002 (2002ApJ...575..484G) 42 = Hawley+2002 (J/AJ/123/3409) 43 = Kendall+2004 (2004A&A...416L..17K) 44 = Kirkpatrick+2000 (2000AJ....120..447K) 45 = Kirkpatrick+2001 (2001AJ....121.3235K) 46 = Kirkpatrick+2008 (J/ApJS/190/100) 47 = Kirkpatrick+2010 (J/AJ/127/3553) 48 = Kirkpatrick+1999 (2003AJ....125..343L) 49 = Kirkpatrick+2006 (J/PASP/118/659) 50 = Knapp+2004 (J/AJ/127/3553) 51 = Liebert+2003 (2003AJ....125..343L) 52 = Liebert+2006 (J/PASP/118/659) 53 = Liebert+2007 (2007ApJ...655..522L) 54 = Liu+2013 (2013ApJ...777L..20L) 55 = Liu+2016 (J/ApJ/833/96) 56 = Looper+2007 (J/AJ/134/1162) 57 = Looper+2008a (2008ApJ...685.1183L) 58 = Looper+2008b (2008ApJ...686..528L) 59 = Luhman+2007 (2007ApJ...654..570L) 60 = Manjavacas+2019 (J/AJ/157/101) 61 = Marocco+2013 (2013AJ....146..161M) 62 = Marocco+2015 (J/MNRAS/449/3651) 63 = McElwain+2006 (2006AJ....132.2074M) 64 = Metchev+2008 (J/ApJ/676/1281) 65 = Phan-Bao+2008 (J/MNRAS/383/831) 66 = Pineda+2016 (2016ApJ...826...73P) 67 = Reid+2006 (2006ApJ...639.1114R) 68 = Reid+2008 (J/AJ/136/1290) 69 = Schmidt+2010b (J/AJ/139/1808) 70 = Schneider+2014 (J/AJ/147/34) 71 = Sheppard+2009 (2009AJ....137..304S) 72 = Siegler+2007 (2007PhDT........11S) 73 = Smart+2013 (2013MNRAS.433.2054S) 74 = Smart+2018 (J/MNRAS/481/3548) 75 = Tinney+2003 (2003AJ....126..975T) 76 = Tinney+2014 (2014ApJ...796...39T) 77 = Vrba+2004 (2004AJ....127.2948V) 78 = Wilson+2001 (2001AJ....122.1989W) 79 = Wilson+2003 (2003IAUS..211..197W) 80 = Zhang+2009 (J/A+A/497/619) 81 = Stumpf+2009 (2009AIPC.1094..561S) 82 = Bardalez Gagliuffi+2019 (J/ApJ/883/205) 83 = Scholz+2002 (2002MNRAS.336L..49S) 84 = Schmidt+2010a (2010AJ....139.1045S) -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Robin Leichtnam [CDS] 17-Apr-2026