J/A+A/708/A378 Planetary-mass binaries in Lower Centaurus-Crux (Caceres+, 2026)
Discovery of planetary-mass binaries in the Lower Centaurus-Crux association.
Caceres C., Minniti D., Mejias A., Gomez M., Alonso-Garcia J., Ivanov V.D.,
Pullen J.B., Saito R.K., Smith L.C., Solano E., Beamin J.C., Rojas-Bozza D.,
Soto P., Zelada R.
<Astron. Astrophys. 708, A378 (2026)>
=2026A&A...708A.378C 2026A&A...708A.378C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ;
Keywords: surveys - planets and satellites: general - binaries: general -
brown dwarfs - stars: low-mass
Abstract:
The recent discovery of free-floating planets (FFPs) in nearby young
stellar associations suggests that these objects might be common in
the Galaxy. Our search for FFPs in the young Lower Centaurus-Crux
Association (LCC) using the VISTA Variables in the Via Lactea VVV
and VVVX surveys revealed several candidates with distances d<200pc.
The main goal of the paper is to identify binary FFPs among this
sample. The presence of such binaries is useful to contrast two
different main formation scenarios: the formation in the circumstellar
disk of the parent star with subsequent ejection by dynamical
interactions and the in-situ formation by gravitational collapse of a
protostellar cloud.
We use the Gaia, VVV, VVVX, and DECaPS databases to identify pairs of
low-mass objects in the LCC association sharing common proper motions.
We examine the optical and near-IR color-magnitude and color-color
diagrams, and visually confirm the detections in the available optical
and near-IR images.
We find 17 young low-mass binaries in the LCC association, with
distances starting from 68pc and projected separations ranging from
88au to 6742au. A couple of candidates have additional faint
companions that need confirmation to secure them as triple systems.
Adopting an age of 17Myr for the LCC association, we find that 14 of
the components are faint enough to have planetary masses.
Our results indicate that binaries represent ≳2% of the population of
FFPs in the LCC association, and suggest that their preferred
formation mechanism is the gravitational collapse independent of a
star. Also, many of the recently discovered FFPs in LCC may be
unresolved giant binary planets. The wide range of colors and flux
reversals observed suggests that the existence of clouds in their
atmospheres is important and points to continuity with the BD
populations.
Description:
Identifications, astrometry, and photometry of the candidates binary
FFPs in LCC.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 149 35 Identifications, astrometry, and photometry of
the candidates binary FFPs in LCC
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- VVV-FFP ID of object
6- 24 I19 --- GaiaDR3 Gaia DR3 ID
26- 37 F12.8 deg RAdeg Gaia DR3 Right Ascension (J2000)
39- 50 F12.8 deg DEdeg Gaia DR3 Declination (J2000)
52- 56 F5.2 mas plx Gaia DR3 parallax
58- 61 F4.2 mas e_plx Gaia DR3 parallax error
63- 68 F6.2 mas/yr pmRA Gaia DR3 proper motion in RA
70- 73 F4.2 mas/yr e_pmRA Gaia DR3 proper motion in RA error
75- 80 F6.2 mas/yr pmDE Gaia DR3 proper motion in DEC
82- 85 F4.2 mas/yr e_pmDE Gaia DR3 proper motion in DEC error
87- 90 F4.2 mag ruwe Gaia DR3 ruwe
92- 96 F5.2 mag Gmag Gaia DR3 G magnitude
98-101 F4.2 mag G-RP ?=- Gaia DR3 (G - GRP) color
103-106 F4.2 mag BP-RP ?=- Gaia DR3 (GBP-GRP) color
108-112 F5.2 mag Jmag VVV/X J magnitude
114-117 F4.2 mag J-Ks VVV/X (J-Ks) color
119-122 I4 pc Dist Distance
124 A1 --- l_Mass Limit flag on Mass
125-129 F5.1 MJup Mass Estimated mass
132-135 F4.1 arcsec AngSep Angular separation
137-140 I4 AU ProjSep Projected separation
142-149 E8.3 10-7W BindE Binding energy of system
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Acknowledgements:
C. Caceres, cccacere(at)gmail.com
(End) Patricia Vannier [CDS] 03-Feb-2026