J/A+A/685/A6 Gaia Ultra-Cool Dwarf candidates IR spectra (Ravinet+, 2024)
Near-infrared spectroscopic characterisation of Gaia ultra-cool dwarf
candidates. Spectral types and pecularities.
Ravinet T., Reyle C., Lagarde N., Burgasser A., Smart R.L., Moya W.H.,
Marocco F., Scholz R.-D., Cooper W.J., Cruz K.L., Fernandez-Trincado J.G.,
Homeier D., Sarro L.M.
<Astron. Astrophys. 685, A6 (2024)>
=2024A&A...685A...6R 2024A&A...685A...6R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, brown dwarf ; Stars, late-type ;
MK spectral classification ; Spectra, infrared
Keywords: surveys - brown dwarfs - stars: late-type - stars: low-mass -
infrared: stars
Abstract:
The local census of very low-mass stars and brown dwarfs is crucial to
improving our understanding of the stellar-substellar transition and
their formation history. These objects, known as ultra-cool dwarfs
(UCDs), are essential targets for searches of potentially habitable
planets. However, their detection poses a challenge because of their
low luminosity. The Gaia survey has identified numerous new UCD
candidates thanks to its large survey and precise astrometry.
We aim to characterise 60 UCD candidates detected by Gaia in the solar
neighbourhood with a spectroscopic follow-up to confirm that they are
UCDs, as well as to identify peculiarities.
We acquired the near-infrared (NIR) spectra of 60 objects using the
SOFI spectrograph between 0.93 and 2.5 microns (R∼600). We
identified their spectral types using a template-matching method.
Their binarity is studied using astrometry and spectral features.
We confirm that 60 objects in the sample have ultra-cool dwarf
spectral types close to those expected from astrometry. Their NIR
spectra reveal that seven objects could host an unresolved coolest
companion and seven UCDs share the same proper motions as other stars.
The characterisation of these UCDs is part of a coordinated effort to
improve our understanding of the Solar neighbourhood.
Description:
We tabulate the spectral types of 60 UCDs from the Gaia DR3 release
and of earlier-type binary companions. In the table, we provide the
shortname, Gaia DR3 ID, Gaia G, G_BP, G_RP magnitudes and
uncertainties, 2MASS J, H, Ks magnitudes and uncertainties. We also
provide the spectral type derived from a template matching method.
Effective temperatures and uncertainties derived with a MCMC method
are also provided, issued from BT-Settl (CIFIST) models.
The objects near-infrared spectra, observed with SOFI (NTT, la Silla)
are also provided, in Flambda units.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled.dat 217 64 List of studied stars (tables D1+D2)
fits/* . 64 Individual fits spectra
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: tabled.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- SName Shortname of the object (JHHMM+DDMM),
as in table D1
11 A1 --- n_SName [a] Note on Name (1)
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 22 F4.1 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign (J2000)
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 34 F4.1 arcsec DEs Declination (J2000)
36- 41 F6.3 mas plx Parallax
43- 47 F5.3 mas e_plx Parallax error
49- 56 F8.3 mas/yr pmRA Proper motion along RA
58- 62 F5.3 mas/yr e_pmRA Proper motion along RA error
64- 71 F8.3 mas/yr pmDE Proper motion along DE
73- 77 F5.3 mas/yr e_pmDE Proper motion along DE error
79- 84 F6.2 km/s Vtan Tangential velocity
86- 89 F4.2 km/s e_Vtan Tangential velocity error
91-101 A11 --- SName2 Shortname of the object (JHHMM+DDMM),
as in table D2
103-121 I19 --- GaiaDR3 Gaia DR3 source ID
123-127 F5.2 mag Gmag Gaia G apparent magnitude
129-132 F4.2 mag e_Gmag Gaia G apparent magnitude rms uncertainty
134-138 F5.2 mag RPmag Gaia G_RP apparent magnitude
140-143 F4.2 mag e_RPmag Gaia G_RP apparent magnitude rms uncertainty
145-149 F5.2 mag Jmag 2MASS J apparent magnitude
151-154 F4.2 mag e_Jmag 2MASS J apparent magnitude rms uncertainty
156-160 F5.2 mag Hmag 2MASS H apparent magnitude
162-165 F4.2 mag e_Hmag 2MASS H apparent magnitude rms uncertainty
167-171 F5.2 mag Ksmag 2MASS Ks apparent magnitude
173-176 F4.2 mag e_Ksmag 2MASS Ks apparent magnitude rms uncertainty
178-192 A15 --- SpType Spectral type
194-197 I4 K Teff ? Effective temperature, derived using
BT-Settl (CIFIST) models
199-200 I2 K e_Teff ? Effective temperature uncertainty
202-217 A16 --- FileName Name of the fits spectrum file in
subdirectory fits
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Note (1): Note as follows:
a = Not an UCD candidate, observed as in a binary system with a UCD candidate
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History:
30-Apr-2024: From Thomas Ravinet, thomas.ravinet(at)univ-fcomte.fr
17-Jan-2025: Table D corrected (error from CDS)
Acknowledgements:
This work has made use of data from the European Space Agency
(ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the
Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). This research
has made use of the SIMBAD database, operated at CDS, Strasbourg,
France. Based on observations collected at the European Organisation
for Astronomical Research in the Southern Hemisphere under ESO
programmes 106.214E.001 and 108.22G4.001.
(End) Patricia Vannier [CDS] 12-Feb-2024