J/MNRAS/499/5302 Ultracool dwarfs in wide binaries (dal Ponte+, 2020)
Increasing the census of ultracool dwarfs in wide binary and multiple systems
using Dark Energy Survey DR1 and Gaia DR2 data.
dal Ponte M., Santiago B., Carnero Rosell A., Burningham B., Yanny B.,
Marshall J.L., Bechtol K., Martini P., Li T.S., De Paris L., Abbott T.M.C.,
Aguena M., Allam S., Avila S., Bertin E., Bhargava S., Brooks D.,
Buckley-Geer E., Carrasco Kind M., Carretero J., da Costa L.N.,
De Vicente J., Diehl H.T., Doel P., Eifler T.F., Everett S., Flaugher B.,
Fosalba P., Frieman J., Garcia-Bellido J., Gaztanaga E., Gerdes D.W.,
Gruen D., Gruendl R.A., Gschwend J., Gutierrez G., Hinton S.R.,
Hollowood D.L., Honscheid K., James D.J., Kuehn K., Kuropatkin N.,
Maia M.A.G., March M., Menanteau F., Miquel R., Palmese A.,
Paz-Chinchon F., Plazas A.A., Sanchez E., Scarpine V., Serrano S.,
Sevilla-Noarbe I., Smith M., Suchyta E., Swanson M.E.C., Tarle G.,
Thomas D., Varga T.N., Walker A.R., (the DES Collaboration)
<Mon. Not. R. Astron. Soc., 499, 5302-5317 (2020)>
=2020MNRAS.499.5302D 2020MNRAS.499.5302D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, brown dwarf ;
Positional data ; Spectral types ; Proper motions ;
Stars, distances ; Stars, masses ; Optical
Keywords: binaries: general - brown dwarfs - stars: low-mass
Abstract:
We present the discovery of 255 binary and 6 multiple system
candidates with wide (>5arcsec) separation composed by ultracool
dwarfs (UCDs) companions to stars, plus nine double ultracool dwarf
systems. These systems were selected based on common distance
criteria. About 90 per cent of the total sample has proper motions
available and 73 per cent of the systems also satisfy a common proper
motion criterion. The sample of ultracool candidates was taken from
the Dark Energy Survey (DES) and the candidate stellar primaries are
from Gaia DR2 and DES data. We compute chance alignment probabilities
in order to assess the physical nature of each pair. We find that 174
candidate pairs with Gaia DR2 primaries and 81 pairs with a DES star
as a primary have chance alignment probabilities <5 per cent. Only
nine candidate systems composed of two UCDs were identified. The
sample of candidate multiple systems is made up of five triple systems
and one quadruple system. The majority of the UCDs found in binaries
and multiples are of early L type and the typical wide binary fraction
over the L spectral types is 2-4 per cent. Our sample of candidate
wide binaries with UCDs as secondaries constitutes a substantial
increase over the known number of such systems, which are very useful
to constrain the formation and evolution of UCDs.
Description:
DES is a (∼5000deg2) optical survey in the grizY bands of the Dark
Energy Camera (DECam; Flaugher et al. 2015AJ....150..150F 2015AJ....150..150F). DECam is a
wide-field (3deg2) imager at the prime focus of the Blanco 4m
telescope in Cerro Tololo Inter-American Observatory (CTIO). The first
public data release of the Dark Energy Survey, DES DR1 (DR1; Abbott et
al. 2018ApJS..239...18A 2018ApJS..239...18A) is composed of 345 distinct nights spread
over the first three years of DES operations, from 2013 August 15 to
2016 February 12.
As presented in Carnero Rosell et al. (2019MNRAS.489.5301C 2019MNRAS.489.5301C, Cat.
J/MNRAS/489/5301), our search of ultracool dwarf (UCD) candidates in
the combination of DES, VHS and AllWISE data was performed using a
colour-colour cut criteria. The adopted cuts to select our candidates
was (iAB-zAB)>1.2, (zAB-YAB)>0.15 and (YAB-JVega)>1.6.
The Gaia astrometric mission was launched in December 2013. It is
measuring positions, parallaxes, proper motions and photometry for
over one billion sources to G∼20.7. Its Data Release 2 (Gaia DR2; Gaia
Collaboration et al. 2018A&A...616A...1G 2018A&A...616A...1G, Cat. I/345), has covered the
initial 22 months of data taking (from a predicted total of 5yr), with
positions and photometry for 1.7x109 sources and full astrometric
solution for 1.3x109.
For our purpose, we used Gaia DR2 data to select primary star
candidates. Particularly important for this work are the parallaxes,
whose precision varies from <0.1mas for G=<17 to ∼0.7mas for G=20.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 346 259 The common distance pair candidates identified
using the UCD sample combined to Gaia DR2 and
DES DR1 data
table2.dat 330 9 The nine common distance pair candidates
identified among the UCD sample and the letters
A and B represent a different UCD
table3.dat 524 6 The common distance multiple systems found in
our search
tablea1.dat 86 121 Known systems, which contain a L or T dwarf as
a secondary, all are spectroscopically confirmed
tablea2.dat 100 34 The common distance and common proper motion
wide systems identified in the literature
refs.dat 84 78 References for Table A1
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)
J/MNRAS/489/5301 : DES Y3 substellar LT and M catalogs (Carnero Rosell+, 2019)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID System identifier (JHHMM+DDMM)
12 A1 --- f_ID [*] Flag on ID (1)
14- 23 F10.6 deg RAdeg Right ascension (J2000) of the primary star
25- 34 F10.6 deg DEdeg Declination (J2000) of the primary star
36- 37 I2 h RAAh Right ascension (J2000) of the primary star
39- 40 I2 min RAAm Right ascension (J2000) of the primary star
42- 43 I2 s RAAs Right ascension (J2000) of the primary star
45 A1 --- DEA- Declination sign (J2000) of the primary star
46- 47 I2 deg DEAd Declination (J2000) of the primary star
49- 50 I2 arcmin DEAm Declination (J2000) of the primary star
52- 53 I2 arcsec DEAs Declination (J2000) of the primary star
55- 64 F10.6 deg RABdeg Right ascension (J2000) of the ultracool
dwarf
66- 75 F10.6 deg DEBdeg Declination (J2000) of the ultracool dwarf
77- 78 I2 h RAB2h Right ascension (J2000) of the ultracool
dwarf
80- 81 I2 min RAB2m Right ascension (J2000) of the ultracool
dwarf
83- 84 I2 s RAB2s Right ascension (J2000) of the ultracool
dwarf
86 A1 --- DEB2- Declination sign (J2000) of the ultracool
dwarf
87- 88 I2 deg DEB2d Declination (J2000) of the ultracool dwarf
90- 91 I2 arcmin DEB2m Declination (J2000) of the ultracool dwarf
93- 94 I2 arcsec DEB2s Declination (J2000) of the ultracool dwarf
96- 104 F9.6 mag GmagA ? Gaia DR2 G-band magnitude of the primary
star
106- 114 F9.6 mag gmagA ? DES g-band magnitude of the primary star
116- 123 F8.6 mag e_gmagA ? Error on gmagA
125- 133 F9.6 mag rmagA ? DES r-band magnitude of the primary star
135- 142 F8.6 mag e_rmagA ? Error on rmagA
144- 152 F9.6 mag imagA ? DES i-band magnitude of the primary star
154- 161 F8.6 mag e_imagA ? Error on imagA
163- 171 F9.6 mag imagB DES i-band magnitude of the ultracool dwarf
173- 180 F8.6 mag e_imagB Error on imagB
182- 190 F9.6 mag zmagB DES z-band magnitude of the ultracool dwarf
192- 199 F8.6 mag e_zmagB Error on zmagB
201- 209 F9.6 mag YmagB DES B-band magnitude of the ultracool dwarf
211- 218 F8.6 mag e_YmagB Error on YmagB
220- 228 F9.5 pc DistA Distance of the primary star
230- 238 F9.5 pc e_DistA Error on DistA
240- 248 F9.5 pc DistB Distance of the ultracool dwarf
250- 257 F8.5 pc e_DistB Error on DistB
259- 261 A3 --- SpTypeA Spectral type of the primary star
263- 264 A2 --- SpTypeB Spectral type of the ultracool dwarf
266- 272 F7.3 mas/yr pmRAA ? Proper motion in right ascension of the
primary star
274- 278 F5.3 mas/yr e_pmRAA ? Error on pmRAA
280- 286 F7.3 mas/yr pmDEA ? Proper motion in declination of the primary
star
288- 292 F5.3 mas/yr e_pmDEA ? Error on pmDEA
294- 300 F7.2 mas/yr pmRAB ? Proper motion in right ascension of the
ultracool dwarf
302- 306 F5.1 mas/yr e_pmRAB ? Error on pmRAB
308- 314 F7.2 mas/yr pmDEB ? Proper motion in declination of the
ultracool dwarf
316- 320 F5.1 mas/yr e_pmDEB ? Error on pmDEB
322- 329 F8.5 arcsec Dtheta Angular separation Δθ
331- 338 F8.2 AU dp Projected separation dp
340- 346 F7.5 % Pa Chance alignment probability (G1)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
* = The distance for Gaia DR2 stars was published by Anders et al.
(2019A&A...628A..94A 2019A&A...628A..94A, Cat. I/349)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID System identifier (JHHMM+DDMM)
12 A1 --- f_ID [*] Flag on ID (1)
14- 23 F10.6 deg RAdeg Right ascension (J2000) of the first
ultracool dwarf
25- 34 F10.6 deg DEdeg Declination (J2000) of the first ultracool
dwarf
36- 37 I2 h RAAh Right ascension (J2000) of the first
ultracool dwarf
39- 40 I2 min RAAm Right ascension (J2000) of the first
ultracool dwarf
42- 43 I2 s RAAs Right ascension (J2000) of the first
ultracool dwarf
45 A1 --- DEA- Declination sign (J2000) of the first
ultracool dwarf
46- 47 I2 deg DEAd Declination (J2000) of the first ultracool
dwarf
49- 50 I2 arcmin DEAm Declination (J2000) of the first ultracool
dwarf
52- 53 I2 arcsec DEAs Declination (J2000) of the first ultracool
dwarf
55- 64 F10.6 deg RABdeg Right ascension (J2000) of the second
ultracool dwarf
66- 75 F10.6 deg DEBdeg Declination (J2000) of the second ultracool
dwarf
77- 78 I2 h RAB2h Right ascension (J2000) of the second
ultracool dwarf
80- 81 I2 min RAB2m Right ascension (J2000) of the second
ultracool dwarf
83- 84 I2 s RAB2s Right ascension (J2000) of the second
ultracool dwarf
86 A1 --- DEB2- Declination sign (J2000) of the second
ultracool dwarf
87- 88 I2 deg DEB2d Declination (J2000) of the second ultracool
dwarf
90- 91 I2 arcmin DEB2m Declination (J2000) of the second ultracool
dwarf
93- 94 I2 arcsec DEB2s Declination (J2000) of the second ultracool
dwarf
96- 104 F9.6 mag imagA DES i-band magnitude of the first ultracool
dwarf
106- 113 F8.6 mag e_imagA Error on imagA
115- 123 F9.6 mag zmagA DES z-band magnitude of the first ultracool
dwarf
125- 132 F8.6 mag e_zmagA Error on zmagA
134- 142 F9.6 mag YmagA DES Y-band magnitude of the first ultracool
dwarf
144- 151 F8.6 mag e_YmagA Error on YmagA
153- 161 F9.6 mag imagB ? DES i-band magnitude of the second
ultracool dwarf
163- 170 F8.6 mag e_imagB ? Error on imagB
172- 180 F9.6 mag zmagB DES z-band magnitude of the second ultracool
dwarf
182- 189 F8.6 mag e_zmagB Error on zmagB
191- 199 F9.6 mag YmagB DES Y-band magnitude of the second ultracool
dwarf
201- 208 F8.6 mag e_YmagB Error on YmagB
210- 218 F9.5 pc DistA Distance of the first ultracool dwarf
220- 227 F8.5 pc e_DistA Error on DistA
229- 237 F9.5 pc DistB Distance of the second ultracool dwarf
239- 246 F8.5 pc e_DistB Error on DistB
248- 249 A2 --- SpTypeA Spectral type of the first ultracool dwarf
251- 252 A2 --- SpTypeB Spectral type of the second ultracool dwarf
254- 259 F6.2 mas/yr pmRAA ? Proper motion in right ascension of the
first ultracool dwarf
261- 265 F5.1 mas/yr e_pmRAA ? Error on pmRAA
267- 272 F6.2 mas/yr pmDEA ? Proper motion in declination of the first
ultracool dwarf
274- 278 F5.1 mas/yr e_pmDEA ? Error on pmDEA
280- 286 F7.2 mas/yr pmRAB ? Proper motion in right ascension of the
second ultracool dwarf
288- 292 F5.1 mas/yr e_pmRAB ? Error on pmRAB
294- 299 F6.2 mas/yr pmDEB ? Proper motion in declination of the second
ultracool dwarf
301- 305 F5.1 mas/yr e_pmDEB ? Error on pmDEB
307- 315 F9.5 arcsec Dtheta Angular separation Δθ
317- 324 F8.2 AU dp Projected separation dp
326- 330 F5.3 % Pa Chance alignment probability (G1)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
* = Common proper motion system
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID System identifier (JHHMM+DDMM)
12 A1 --- f_ID [*] Flag on ID (1)
14- 23 F10.6 deg RAdeg Right ascension (J2000) of the first star
25- 34 F10.6 deg DEdeg Declination (J2000) of the first star
36- 37 I2 h RAAh Right ascension (J2000) of the first star
39- 40 I2 min RAAm Right ascension (J2000) of the first star
42- 43 I2 s RAAs Right ascension (J2000) of the first star
45 A1 --- DEA- Declination sign (J2000) of the first star
46- 47 I2 deg DEAd Declination (J2000) of the first star
49- 50 I2 arcmin DEAm Declination (J2000) of the first star
52- 53 I2 arcsec DEAs Declination (J2000) of the first star
55- 64 F10.6 deg RABdeg Right ascension (J2000) of the second star
66- 75 F10.6 deg DEBdeg Declination (J2000) of the second star
77- 78 I2 h RAB2h Right ascension (J2000) of the second star
80- 81 I2 min RAB2m Right ascension (J2000) of the second star
83- 84 I2 s RAB2s Right ascension (J2000) of the second star
86 A1 --- DEB2- Declination sign (J2000) of the second star
87- 88 I2 deg DEB2d Declination (J2000) of the second star
90- 91 I2 arcmin DEB2m Declination (J2000) of the second star
93- 94 I2 arcsec DEB2s Declination (J2000) of the second star
96- 105 F10.6 deg RACdeg Right ascension (J2000) of the ultracool
dwarf
107- 116 F10.6 deg DECdeg Declination (J2000) of the ultracool dwarf
118- 119 I2 h RAC2h Right ascension (J2000) of the ultracool
dwarf
121- 122 I2 min RAC2m Right ascension (J2000) of the ultracool
dwarf
124- 125 I2 s RAC2s Right ascension (J2000) of the ultracool
dwarf
127 A1 --- DEC2- Declination sign (J2000) of the ultracool
dwarf
128- 129 I2 deg DEC2d Declination (J2000) of the ultracool dwarf
131- 132 I2 arcmin DEC2m Declination (J2000) of the ultracool dwarf
134- 135 I2 arcsec DEC2s Declination (J2000) of the ultracool dwarf
137- 145 F9.6 mag GmagA Gaia DR2 G-band magnitude of the first star
147- 155 F9.6 mag gmagA ? DES g-band magnitude of the first star
157- 164 F8.6 mag e_gmagA ? Error on gmagA
166- 174 F9.6 mag rmagA ? DES r-band magnitude of the first star
176- 183 F8.6 mag e_rmagA ? Error on rmagA
185- 193 F9.6 mag imagA ? DES i-band magnitude of the first star
195- 202 F8.6 mag e_imagA ? Error on imagA
204- 212 F9.6 mag GmagB ? Gaia DR2 G-band magnitude of the second
star
214- 222 F9.6 mag gmagB ? DES g-band magnitude of the second star
224- 231 F8.6 mag e_gmagB ? Error on gmagB
233- 241 F9.6 mag rmagB ? DES r-band magnitude of the second star
243- 250 F8.6 mag e_rmagB ? Error on rmagB
252- 260 F9.6 mag imagB ? DES i-band magnitude of the second star
262- 269 F8.6 mag e_imagB ? Error on imagB
271- 279 F9.6 mag imagC DES i-band magnitude of the ultracool dwarf
281- 288 F8.6 mag e_imagC Error on imagC
290- 298 F9.6 mag zmagC DES z-band magnitude of the ultracool dwarf
300- 307 F8.6 mag e_zmagC Error on zmagC
309- 317 F9.6 mag YmagC DES Y-band magnitude of the ultracool dwarf
319- 326 F8.6 mag e_YmagC Error on YmagC
328- 336 F9.5 pc DistA Distance of the first star
338- 345 F8.5 pc e_DistA Error on DistA
347- 355 F9.5 pc DistB Distance of the second star
357- 364 F8.5 pc e_DistB Error on DistB
366- 374 F9.5 pc DistC Distance of the ultracool dwarf
376- 383 F8.5 pc e_DistC Error on DistC
385- 386 A2 --- SpTypeB Spectral type of the second star
388- 389 A2 --- SpTypeC Spectral type of the ultracool dwarf
391- 397 F7.3 mas/yr pmRAA Proper motion in right ascension of the
first star
399- 403 F5.3 mas/yr e_pmRAA Error on pmRAA
405- 412 F8.3 mas/yr pmDEA Proper motion in declination of the first
star
414- 418 F5.3 mas/yr e_pmDEA Error on pmDEA
420- 426 F7.3 mas/yr pmRAB Proper motion in right ascension of the
second star
428- 433 F6.3 mas/yr e_pmRAB Error on pmRAB
435- 442 F8.3 mas/yr pmDEB Proper motion in declination of the second
star
444- 449 F6.3 mas/yr e_pmDEB Error on pmDEB
451- 456 F6.2 mas/yr pmRAC Proper motion in right ascension of the
ultracool dwarf
458- 461 F4.1 mas/yr e_pmRAC Error on pmRAC
463- 468 F6.2 mas/yr pmDEC Proper motion in declination of the
ultracool dwarf
470- 473 F4.1 mas/yr e_pmDEC Error on pmDEC
475- 482 F8.5 arcsec DthetaAB Angular separation Δθ of the
first and second stars
484- 490 F7.2 AU dpAB Projected separation dp of the first and
second stars
492- 499 F8.5 arcsec DthetaAC Angular separation Δθ of the
first star and the ultracool dwarf
501- 507 F7.2 AU dpAC Projected separation dp of the first star
and the ultracool dwarf
509- 516 F8.5 arcsec DthetaBC Angular separation Δθ of the
second star and the ultracool dwarf
518- 524 F7.2 AU dpBC Projected separation dp of the second star
and the ultracool dwarf
--------------------------------------------------------------------------------
Note (1): Flag as follows:
* = Common proper motion system
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 25 A25 --- Name Object name
27- 32 F6.2 arcsec Dtheta Angular separation
34- 38 I5 AU dp Projected separation
40- 44 F5.1 pc Dist ? Distance
46- 54 A9 --- SpTypeB Spectral type of the companion
56- 64 A9 --- SpTypeA Spectral type of the primary star
66- 77 A12 Msun Mass Mass
79- 86 A8 --- Ref Reference
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Object name
26 A1 --- f_Name Flag on Name (1)
28- 33 F6.1 arcsec Dtheta Angular separation
35- 40 I6 AU dp Projected separation
42- 49 F8.4 pc Dist Distance
51- 54 F4.1 pc e_Dist ? Error on Dist
56- 60 A5 --- SpTypeB Spectral type of the companion
62- 66 A5 --- SpTypeA Spectral type of the primary star
68- 75 F8.3 mas/yr pmRA Proper motion in right ascension
77- 82 F6.3 mas/yr e_pmRA Error on pmRA
84- 91 F8.3 mas/yr pmDE Proper motion in declination
93- 98 F6.3 mas/yr e_pmDE Error on pmDE
100 I1 --- Ref Reference (2)
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Note (1): Flag as follows:
a = This is the only bound system in Smart et al. (2017MNRAS.469..401S 2017MNRAS.469..401S,
Cat. J/MNRAS/469/401)
b = Classify as unlikely pair (Marocco et al. 2017MNRAS.470.4885M 2017MNRAS.470.4885M)
Note (2): Reference as follows:
1 = Smart et al. (2017MNRAS.469..401S 2017MNRAS.469..401S, Cat. J/MNRAS/469/401)
2 = Marocco et al. (2017MNRAS.470.4885M 2017MNRAS.470.4885M)
3 = Kirkpatrick et al. (2016ApJS..224...36K 2016ApJS..224...36K, Cat. J/ApJS/224/36)
4 = Best et al. (2015ApJ...814..118B 2015ApJ...814..118B, Cat. J/ApJ/814/118)
5 = Smart et al. (2019MNRAS.485.4423S 2019MNRAS.485.4423S, Cat. J/MNRAS/485/4423)
6 = Smith et al. (2014MNRAS.437.3603S 2014MNRAS.437.3603S, Cat. J/MNRAS/437/3603)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref [1/78] Reference number
4- 22 A19 --- BibCode BibCode
24- 67 A44 --- Aut Author's name
69- 84 A16 --- Com Comments
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Global Notes:
Note (G1): We estimate the chance alignment probability following a similar
procedure used by Smart et al. (2017MNRAS.469..401S 2017MNRAS.469..401S,
Cat. J/MNRAS/469/401) and Dhital et al. (2015AJ....150...57D 2015AJ....150...57D,
Cat. J/AJ/150/57). The chance alignment probability is the
probability that we find a physically unrelated object with the same
common distance within our uncertainties and within the search
radius. To assess the chance alignment probability, we simulate
stars within a 2deg2 area from the UCD candidate from each pair
using Trilegal (Girardi et al. 2005A&A...436..895G 2005A&A...436..895G). See Section 4.1
of the article for more details.
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 11-Sep-2023