J/A+A/696/A80 LDN 1495 free-floating planetary mass objects (Bouy+, 2025)
Free-floating planetary mass objects in LDN 1495 from
Euclid Early Release Observations.
Bouy H., Martin E.L., Cuillandre J.-C., Barrado D., Tamura M., Bertin E.M.,
Zerjal , Points S., Olivares J., Huelamo N., Rodrigues T.
<Astron. Astrophys. 696, A80 (2025)>
=2025A&A...696A..80B 2025A&A...696A..80B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; YSOs ; Photometry ; Infrared ; Optical
Keywords: brown dwarfs - star formation
Abstract:
Substellar objects, including brown dwarfs and free-floating
planetary-mass objects, are a significant product of star formation.
Their sensitivity to initial conditions and early dynamical evolution
makes them especially valuable for studying both planetary and stellar
formation processes. We search for brown dwarfs and isolated planetary
mass objects in a young star forming region to better constrain their
formation mechanisms. We take advantage of Euclid unprecedented
sensitivity, spatial resolution and wide-field of view to search for
brown dwarfs and free-floating planetary mass objects in the LDN 1495
region of the Taurus molecular clouds. We combine the recent Euclid
Early Release Observations with older very deep ground-based images
obtained over more than 20 yr to derive proper motions and
multi-wavelength photometry, and select members based on their
morphology and their position in a proper motion diagram and in 9
color-magnitude diagrams. We identify 15 point sources with proper
motions, colors, and luminosity consistent with being members of LDN
1495. Six of these objects were already known M9-L1 members. The
remaining nine are newly identified sources that could have spectral
types ranging from late-M to early-T with masses potentially as low as
1∼2MJup based on their luminosity and according to evolutionary
models. However, follow-up observations are needed to confirm their
nature, spectral type and membership. If extrapolated to the entire
Taurus star forming region, this result suggests the potential
presence of several dozen free-floating planetary mass objects.
Description:
We presented Euclid Early Release Observations of the LDN 1495
molecular cloud in the Taurus star-forming region. We complemented the
Euclid observations with deep wide-field ground-based images obtained
at various facilities over the past 20 years, as well as with newly
reprocessed Spitzer deep stacks. We selected members based on rather
conservative criteria on their morphology, their proper motion, and
their positions in nine color-magnitude diagrams and obtained a list
of 15 ultracool dwarf candidate members, including 9 new objects and 6
previously confirmed members.
Table 1 : coordinates, proper motion, morphometric and photometric
measurements for the ultracool members of L1495 identified in this
study.
Table B1 : Absolute magnitudes of known young or low-gravity
ultra-cool objects from the literature in the z-filter, Euclid filters
and Spitzer IRAC1 and 2 filters.
Taurus : Coordinates, proper motion, morphometric and photometric
measurements for all the sources identified in this study.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 311 15 Candidate members positions, proper motions
and magnitudes
tableb1.dat 97 200 Absolute magnitudes of known young or
low-gravity ultra-cool objects
taurus.dat 331 230128 Catalogue of sources in the the Euclid and
ground based images
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See also:
J/MNRAS/463/1008 : LDN 1495 SCUBA-2 and Herschel data (Ward-Thompson+, 2016)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Object Abell (ACO) cluster number
(JHHMMSS.ss+DDMMSS.s)
21- 28 F8.5 deg RAdeg Right ascension (J2000.0)
30- 37 F8.5 deg DEdeg Declination (J2000.0)
39- 50 E12.6 deg e_RAdeg Error on right ascension (J2000.0)
52- 63 E12.6 deg e_DEdeg Error on declination sign (J2000.0)
65- 68 F4.1 mas/yr pmRA Proper motion in right ascension
70- 74 F5.1 mas/yr pmDE Proper motion in declination
76- 78 F3.1 mas/yr e_pmRA Error on proper motion in right ascension
80- 82 F3.1 mas/yr e_pmDE Error on proper motion in declination
84- 88 F5.2 mag rmag ?=- r magnitude
90- 93 F4.2 mag e_rmag ?=- Error on r magnitude
95- 99 F5.2 mag imag ?=- i magnitude
101-104 F4.2 mag e_imag ?=- Error on i magnitude
106-110 F5.2 mag zmag z magnitude
112-115 F4.2 mag e_zmag Error on z magnitude
117-121 F5.2 mag ymag y magnitude
123-126 F4.2 mag e_ymag Error on y magnitude
128-132 F5.2 mag Jmag J magnitude
134-137 F4.2 mag e_Jmag Error on J magnitude
139-143 F5.2 mag Hmag H magnitude
145-148 F4.2 mag e_Hmag Error on H magnitude
150-154 F5.2 mag Ksmag Ks magnitude
156-159 F4.2 mag e_Ksmag Error on Ks magnitude
161-165 F5.2 mag IEmag ?=- Euclid I_E magnitude
167-170 F4.2 mag e_IEmag ?=- Error on Euclid I_E magnitude
172-176 F5.2 mag YEmag Euclid Y_E magnitude
178-181 F4.2 mag e_YEmag Error on Euclid Y_E magnitude
183-187 F5.2 mag JEmag Euclid J_E magnitude
189-192 F4.2 mag e_JEmag Error on Euclid J_E magnitude
194-198 F5.2 mag HEmag Euclid H_E magnitude
200-203 F4.2 mag e_HEmag Error on Euclid H_E magnitude
205-206 I2 --- NposOK Number of epochs
208-217 F10.5 yr Epochmin Earliest epoch
219-228 F10.5 yr Epochmax Last epoch
230-237 F8.5 --- SpreadMod SExtractor SPREAD_MODEL
239-245 F7.5 --- e_SpreadMod Error on SExtractor SPREAD_MODEL
247-251 F5.2 mag I1mag Spitzer IRAC 1 magnitude
253-256 F4.2 mag e_I1mag Error on Spitzer IRAC 1 magnitude
258-262 F5.2 mag I2mag Spitzer IRAC 2 magnitude
264-267 F4.2 mag e_I2mag Error on Spitzer IRAC 2 magnitude
269-273 F5.2 mag I3mag ?=- Spitzer IRAC 3 magnitude
275-278 F4.2 mag e_I3mag ?=- Error on Spitzer IRAC 3 magnitude
280-284 F5.2 mag I4mag ?=- Spitzer IRAC 4 magnitude
286-289 F4.2 mag e_I4mag ?=- Error on Spitzer IRAC 4 magnitude
291-295 F5.2 mag W1mag ?=- unWISE 1 magnitude
297-300 F4.2 mag e_W1mag ?=- Error on unWISE 1 magnitude
302-306 F5.2 mag W2mag ?=- unWISE 2 magnitude
308-311 F4.2 mag e_W2mag ?=- Error on unWISE 2 magnitude
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 31 A31 --- Name Simbad main
33- 41 F9.5 deg RAdeg Right ascension (J2000.0)
43- 51 F9.5 deg DEdeg Declination (J2000.0)
53- 61 A9 --- SpType Spectral type
63- 67 F5.2 mag zmag ?=- z magnitude
69- 73 F5.2 mag YEmag ?=- Euclid Y_E magnitude
75- 79 F5.2 mag JEmag Euclid J_E magnitude
81- 85 F5.2 mag HEmag Euclid H_E magnitude
87- 91 F5.2 mag I1mag ?=- Spitzer IRAC 1 magnitude
93- 97 F5.2 mag I2mag ?=- Spitzer IRAC 2 magnitude
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Byte-by-byte Description of file: taurus.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Object Abell (ACO) cluster number
(JHHMMSS.ss+DDMMSS.s)
21- 28 F8.5 deg RAdeg Right ascension (J2000.0)
30- 37 F8.5 deg DEdeg Declination (J2000.0)
39- 50 E12.6 deg e_RAdeg Error on right ascension (J2000.0)
52- 63 E12.6 deg e_DEdeg Error on declination sign (J2000.0)
65- 75 F11.6 mas/yr pmRA ?=- proper motion in ra
77- 87 F11.6 mas/yr pmDE ?=- proper motion in dec
89- 93 F5.1 mas/yr e_pmRA ?=- Error on proper motion in ra
95- 99 F5.1 mas/yr e_pmDE ?=- Error on proper motion in dec
101-102 I2 --- NposOK Number of epochs
104-113 F10.5 yr Epochmin Earliest epoch
115-124 F10.5 yr Epochmax Last epoch
126-135 F10.6 --- SpreadMod ?=- SExtractor SPREAD_MODEL
137-144 F8.6 --- e_SpreadMod ?=- Error on SExtractor SPREAD_MODEL
146-150 F5.2 mag rmag ?=- r magnitude
152-155 F4.2 mag e_rmag ?=- Error on r magnitude
157-161 F5.2 mag imag ?=- i magnitude
163-166 F4.2 mag e_imag ?=- Error on i magnitude
168-172 F5.2 mag zmag ?=- z magnitude
174-177 F4.2 mag e_zmag ?=- Error on z magnitude
179-183 F5.2 mag ymag ?=- y magnitude
185-188 F4.2 mag e_ymag ?=- Error on y magnitude
190-194 F5.2 mag Jmag ?=- J magnitude
196-199 F4.2 mag e_Jmag ?=- Error on J magnitude
201-205 F5.2 mag Hmag ?=- H magnitude
207-210 F4.2 mag e_Hmag ?=- Error on H magnitude
212-216 F5.2 mag Ksmag ?=- Ks magnitude
218-221 F4.2 mag e_Ksmag ?=- Error on Ks magnitude
223-227 F5.2 mag IEmag ?=- Euclid I_E magnitude
229-232 F4.2 mag e_IEmag ?=- Error on Euclid I_E magnitude
234-238 F5.2 mag YEmag ?=- Euclid Y_E magnitude
240-243 F4.2 mag e_YEmag ?=- Error on Euclid Y_E magnitude
245-249 F5.2 mag JEmag ?=- Euclid J_E magnitude
251-254 F4.2 mag e_JEmag ?=- Error on Euclid J_E magnitude
256-260 F5.2 mag HEmag ?=- Euclid H_E magnitude
262-265 F4.2 mag e_HEmag ?=- Error on Euclid H_E magnitude
267-271 F5.2 mag I1mag ?=- Spitzer IRAC 1 magnitude
273-276 F4.2 mag e_I1mag ?=- Error on Spitzer IRAC 1 magnitude
278-282 F5.2 mag I2mag ?=- Spitzer IRAC 2 magnitude
284-287 F4.2 mag e_I2mag ?=- Error on Spitzer IRAC 2 magnitude
289-293 F5.2 mag I3mag ?=- Spitzer IRAC 3 magnitude
295-298 F4.2 mag e_I3mag ?=- Error on Spitzer IRAC 3 magnitude
300-304 F5.2 mag I4mag ?=- Spitzer IRAC 4 magnitude
306-309 F4.2 mag e_I4mag ?=- Error on Spitzer IRAC 4 magnitude
311-315 F5.2 mag W1mag ?=- unWISE 1 magnitude
317-320 F4.2 mag e_W1mag ?=- Error on unWISE 1 magnitude
322-326 F5.2 mag W2mag ?=- unWISE 2 magnitude
328-331 F4.2 mag e_W2mag ?=- Error on unWISE 2 magnitude
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Acknowledgements:
Herve Bouy, herve.bouy(at)u-bordeaux.fr
(End) Patricia Vannier [CDS] 12-Mar-2025