Access to Astronomical Catalogues

← Click to display the menu
J/AJ/136/1290       Ultracool dwarfs from the 2MASS               (Reid+, 2008)

Meeting the cool neighbors. X. Ultracool dwarfs from the 2MASS all-sky data release. Reid N.I., Cruz K.L., Kirkpatrick J.D., Allen P.R., Mungall F., Liebert J., Lowrance P., Sweet A. <Astron. J., 136, 1290-1311 (2008)> =2008AJ....136.1290R
ADC_Keywords: Stars, nearby ; Proper motions ; Photometry, infrared ; Spectroscopy Keywords: Galaxy: stellar content - stars: low-mass, brown dwarfs - stars: luminosity function, mass function Abstract: Using data from the 2 Micron All Sky Survey All-Sky Point Source Catalogue, we have extended our census of nearby ultracool dwarfs to cover the full celestial sphere above Galactic latitude of 15°. Starting with an initial catalog of 2139484 sources, we have winnowed the sample to 467 candidate late-type M or L dwarfs within 20pc of the Sun. Fifty-four of those sources already have spectroscopic observations confirming them as late-type dwarfs. We present optical spectroscopy of 376 of the remaining 413 sources, and identify 44 as ultracool dwarfs with spectroscopic distances less than 20pc. Twenty-five of the 37 sources that lack optical data have near-infrared spectroscopy. Combining the present sample with our previous results and data from the literature, we catalog 94 L dwarf systems within 2pc. We discuss the distribution of activity, as measured by Hα emission, in this volume-limited sample. We have coupled the present ultracool catalog with data for stars in the northern 8pc sample and recent (incomplete) statistics for T dwarfs to provide a snapshot of the current 20pc census as a function of spectral type. Description: We have obtained intermediate-resolution optical spectroscopy of 376 sources from the 2MUA sample. The overwhelming majority of the observations, covering some 355 sources, were obtained in the course of several observing runs between 2003 March and 2004 February. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 125 54 Previously known cool dwarfs recovered in the 2MUF sample table3.dat 157 57 M6-L8 dwarfs discovered within 20pc table4.dat 142 258 Ultracool dwarfs at distances exceeding 20pc table5.dat 63 83 Spectroscopically confirmed giants table6.dat 63 22 Spectroscopically confirmed Carbon stars table7.dat 125 16 L dwarf spectral standards table8.dat 62 15 L dwarfs with Lithium absorption table9.dat 104 107 L dwarf systems within 20pc of the Sun refs.dat 160 146 References
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/AJ/123/2806 : Nearby stars in the NLTT catalogue (Reid+, 2002) J/AJ/123/2822 : Photometry of southern NLTT stars (Reid+, 2002) J/AJ/123/2828 : Spectroscopy of northern NLTT stars (Cruz+, 2002) J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003) J/AJ/126/2449 : Nearby ultracool dwarfs in galactic plane (Reid+, 2003) J/AJ/126/3007 : Spectroscopy of faint red NLTT dwarfs (Reid+, 2003) J/AJ/128/463 : A preliminary 20pc census from NLTT catalogue (Reid+, 2004) J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007) J/AJ/133/2825 : Star beyond the NLTT catalog (Reid+, 2007) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 16 A16 --- 2MASS 2MASS Designation (HHMMSSss+DDMMSSs) 18- 22 I5 --- 2MUCD 2MUCD Designation 24- 54 A31 --- OName Other Names 56- 61 F6.3 mag Jmag 2MASS J magnitude 63- 67 F5.3 mag J-H 2MASS J-H colour index 69- 73 F5.3 mag J-Ks 2MASS J-Ks colour index 75- 81 A7 --- SpT Optical Spectral Type (G1) 82 A1 --- n_SpT [e] e: Spectral type based on new observations 84- 88 F5.2 mag JMAG ? Absolute J magnitude 90- 93 F4.2 mag e_JMAG ? rms uncertainty on JMAG 94 A1 --- n_JMAG [d] Note on JMAG (1) 96-100 F5.2 pc Dist Heliocentric distance 102-105 F4.2 pc e_Dist rms uncertainty on Dist 106 A1 --- n_Dist [d] Note on Dist (1) 108-125 A18 --- Ref References, in refs.dat file (G2)
Note (1): d = Distance and MJ based on trigonometric parallax.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 16 A16 --- 2MASS 2MASS Designation (HHMMSSss+DDMMSSs) 18- 22 I5 --- 2MUCD ? 2MUCD Designation 24- 47 A24 --- OName Other Names 49- 54 F6.3 mag Jmag ? 2MASS J magnitude 56- 60 F5.3 mag J-H ? 2MASS J-H colour index 62- 66 F5.3 mag J-Ks ? 2MASS J-Ks colour index 68-103 A36 --- ObsDate Observation date(s) 105-111 A7 --- Tel Telescope used 113-121 A9 --- SpT Optical Spectral Type (G1) 123 A1 --- n_SpT [ef] Note on Sptype (1) 125-129 F5.2 mag JMAG ? Absolute J magnitude 131-134 F4.2 mag e_JMAG ? rms uncertainty on JMAG 135 A1 --- n_JMAG [g] Note on JMAG (1) 137 A1 --- l_Dist [~] Limit flag on Dist 138-142 F5.2 pc Dist ? Heliocentric distance 144-147 F4.2 pc e_Dist ? rms uncertainty on Dist 148 A1 --- n_Dist [d] Note on Dist (1) 150-157 A8 --- Ref References, in refs.dat file (G2)
Note (1): Notes as follows: d = Distance and JMAG based on trigonometric parallax e = Displays variable Hα emission as discussed by Schmidt et al. (2007, Cat. J/AJ/133/2258) f = M7: and M8: are estimated to be the component spectral types based on our measured combined spectral type of M7.5 and DeltaI∼1 found by Henry et al., 2004AJ....128.2460H. g = JMAG estimated using 2MASS (J-Ks) color and the spectral-type/MK relation in Dahn et al., 2002AJ....124.1170D.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 16 A16 --- 2MASS 2MASS designation 18 A1 --- n_2MASS [ghi] Individual notes (1) 20- 24 I5 --- 2MUCD IAU designation 26- 54 A29 --- OName Other identification 56- 61 F6.3 mag Jmag 2MASS J band magnitude 63- 67 F5.3 mag J-H 2MASS (J-H) band color 69- 73 F5.3 mag J-Ks 2MASS (J-Ks) band color 75- 88 A14 --- ObsDate ? UT date of observation 90- 96 A7 --- Tel Telescope used in observation 98-105 A8 --- SpT Spectral type (G1) 107 A1 --- n_SpT [df] Spectrum perculiarities (2) 109-113 F5.2 mag JMAG ? Absolute J band magnitude 115-118 F4.2 mag e_JMAG ? Uncertainty in JMAG 120 A1 --- l_Dist [~] Approximate flag in Dist 121-125 F5.1 pc Dist Heliocentric distance 127-131 F5.2 pc e_Dist ? Uncertainty in Dist 133 A1 --- f_Dist [e] Problem in distance (3) 135-142 A8 --- Ref Reference, in refs.dat file (G2)
Note (1): Note as follows: g = Near TW Hydrae Association, but spectrum does not display low-gravity features. We do not have a proper motion measurement h = Companion to LHS 2722, separation ∼2000AU i = In clump near LDN 391 Note (2): Peculiarities as follows: d = Source with Li absorption f = Source with Li and Hα detections Note (3): Distance listed is trigonometric from Tinney et al. (1995AJ....110.3014T) is very different than our spectrophotometric distance of 30.9±2.2. Even unresolved binarity does not account for large difference. Needs more investigation.
Byte-by-byte Description of file: table5.dat table6.dat
Bytes Format Units Label Explanations
1- 16 A16 --- 2MASS 2MASS Designation (HHMMSSss+DDMMSSs) 18- 23 F6.3 mag Jmag 2MASS J magnitude 25- 29 F5.3 mag J-H 2MASS J-H colour index 31- 35 F5.3 mag J-Ks 2MASS J-Ks colour index 37- 47 A11 --- ObsDate Observation date(s) 49- 55 A7 --- Tel Telescope used 57 A1 --- l_SpT [>] Limit on SpT (later) 58- 63 A6 --- SpT Optical Spectral Type (G1)
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1 A1 --- n_2MASS [SP] (S)econdary or (P)rimary standards (1) 3 A1 --- --- [J] 4- 19 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs) 21- 26 A6 --- 2MUCD 2MUCD designation 28- 47 A20 --- OName Other Name 49- 50 A2 --- SpT Spectral Type 52- 57 F6.3 mag Jmag 2MASS J magnitude 59- 64 F6.4 arcsec/yr pm ? Proper motion 66- 71 F6.4 arcsec/yr e_pm ? rms uncertainty on pm 73- 77 F5.1 deg pmPA ? Position angle of proper motion 79- 82 F4.1 deg e_pmPA ? rms uncertainty on pmPA 84- 87 F4.2 --- CrH-a CrH-a spectral index (1) 89- 92 F4.2 --- Rb-b/TiO-b Rb-b/TiO-b spectral index (1) 94- 97 F4.2 --- Cs-a/VO-b Cs-a/VO-b spectral index (1) 99-103 F5.2 --- Color-d ? Color-d spectral index (1) 105 A1 --- Mul? [Y/N?] Multiple? 107-125 A19 --- Ref References, in refs.dat file
Note (1): Primary standards and spectral indices are defined in Kirkpatrick et al. (1999ApJ...519..802K). The indices are defined as flux ratios in spectral ranges (wavelength in Å): CrH-a (CrH λ8611) = F(8580-8600)/F(8621-8641) Rb-b (RbI λ7947.6) = ((F(7922.6-7932.6)+F(7962.6-7972.6))/2/(F(7942.6-7952.6) TiO-b (TiO λ8432) = F(8400-8415)/F(8435-8470) Cs-a (CsI λ8521.1) = ((F(8496.1-8506.1)+F(8536.1-8546.1))/2/F(8516.1-8526.1) VO-b (VO λ7912) = ((F(7860-7880)+F(8080-8100))/F(7960-8000) Color-d = F(9675-9875)/F(7350-7550)
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1 A1 --- n_2MASS [ab] Discovery code (1) 3- 18 A16 --- 2MASS 2MASS Designation (HHMMSSss+DDMMSSs) (G3) 20- 24 I5 --- 2MUCD 2MUCD Designation 26- 29 A4 --- SpT Spectral Type 31- 34 F4.1 0.1nm EW Lithium equivalent width 36- 40 F5.2 pc Dist Heliocentric distance 41- 44 F4.1 mag JMAG ? Absolute J magnitude 46- 62 A17 --- Notes Notes (2)
Note (1): Code as follows: a = L dwarfs from this paper b = L dwarfs from Papers V (J/AJ/126/2421) and IX (J/AJ/133/439) Note (2): References are coded as: V = Cruz et al., 2003, Cat. J/AJ/126/2421, Paper V IX = Cruz et al., 2007, Cat. J/AJ/133/439, Paper IX R = Reid et al., 2006, Cat. J/AJ/132/891
Byte-by-byte Description of file: table9.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Seq Sequential number 3 A1 --- n_Seq [a] NICMOS observation (1) 5- 20 A16 --- 2MASS 2MASS Designation (HHMMSSss+DDMMSSs) (G3) 21- 22 A2 --- m_2MASS Multiplicity index on 2MASS 24- 28 I5 --- 2MUCD ? 2MUCD Designation (2) 29 A1 --- m_2MUCD Multiplicity index on 2MUCD 31- 37 A7 --- SpT Spectral Type 38- 42 F5.2 mag Jmag 2MASS J magnitude 43 A1 --- u_Jmag Uncertainty flag on Jmag 45- 49 F5.2 mag J-H ? 2MASS J-H colour index 50 A1 --- u_J-H Uncertainty flag on J-H 52- 55 F4.2 mag J-Ks ? 2MASS J-Ks colour index 56 A1 --- u_J-Ks Uncertainty flag on J-Ks 58- 62 F5.2 pc Dist ? Heliocentric distance 63 A1 --- --- [/] 64- 68 F5.2 pc Dist2 ? Second value of Distance 69- 72 A4 --- Source [sp trig] Source 74- 92 A19 --- Notes Notes and references 94-104 A11 --- Ref References, in refs.dat file
Note (1): 'a' indicates the L dwarf has HST NICMOS observations (Reid et al. 2006, Cat. J/AJ/132/891, 2008AJ....135..580R) Note (2): Sources from the 2MU2 sample have 2MUCD five-digit numbers 1xxxx; sources from the 2MUA sample have 2MUCD numbers 2xxxx.
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Ref Reference number 5- 23 A19 --- BibCode BibCode 25- 55 A31 --- Aut Author's name 57-160 A104 --- Com Comments
Global notes: Note (G1): Uncertainties on spectral types are ±0.5 subtypes except where noted by one or two colons, indicating an uncertainty of ±1 and ±2 types, respectively. Spectra displaying low-gravity features are indicated with parentheses. Note (G2): References listed pertain to spectral data, resolved binaries, and trigonometric parallaxes. Note (G3): Names published in the 2MASS Intermediate Release (Cat. II/241, discovery code b, designation HHMMSSs+DDMMSS) were replaced at CDS by 2MASS names from final catalog (II/246)
History: From electronic version of the journal References: Reid & Cruz, Paper I 2002AJ....123.2806R, Cat. J/AJ/123/2806 Reid et al., Paper II 2002AJ....123.2822R, Cat. J/AJ/123/2822 Cruz & Reid, Paper III 2002AJ....123.2828C, Cat. J/AJ/123/2828 Reid et al., Paper IV 2003AJ....125..354R, Cat. J/AJ/125/354 Cruz et al., Paper V 2003AJ....126.2421C, Cat. J/AJ/126/2421 Reid, Paper VI 2003AJ....126.2449R, Cat. J/AJ/126/2449 Reid et al., Paper VII 2003AJ....126.3007R, Cat. J/AJ/126/3007 Reid et al., Paper VIII 2004AJ....128..463R, Cat. J/AJ/128/463 Cruz et al., Paper IX 2007AJ....133..439C, Cat. J/AJ/133/439 Reid et al., Paper XI 2007AJ....133.2825R, Cat. J/AJ/133/2825
(End) Patricia Vannier [CDS] 20-Aug-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact