Multiplicity of cool dwarfs

Dupuy, Trent J.; Allen, Peter; Kraus, Adam L.; Biler, B.; Blake, Cullen H.; Davison, C.; Deacon, N. R.; Duchêne, Gaspard; Geller, Aaron M.; King, Robert R.; Law, Nicholas M.; Nguyen, Duy Cuong; Reipurth, Bo; Winters, Jennifer G.; Zhang, ZH

doi:10.1002/asna.201211772

Cited by 2 publications

(2 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cool dwarfs have lower multiplicity fractions than highermass stars (Dupuy et al 2013) with fractions of 26%±3% for stars M 0.1 0.7 - (Duchêne & Kraus 2013), consistent with our results. Our Sco-Cen sample is an order of magnitude smaller than our young field sample, so a detailed statistical comparison of our young field sample and our younger Sco-Cen sample is beyond the scope of this paper.…”

Section: Survey Yields and Expectationssupporting

confidence: 91%

Large Adaptive Optics Survey for Substellar Objects around Young, Nearby, Low-mass Stars with Robo-AO

Salama

Baranec

et al. 2021

View full text Add to dashboard Cite

We present results from the Large Adaptive optics Survey for Substellar Objects, where the goal is to directly image new substellar companions (<70 M Jup ) at wide orbital separations (50 au) around young (300 Myr), nearby (<100 pc), low-mass (≈0.1-0.8 M  ) stars. We report on 427 young stars imaged in the visible (i′) and nearinfrared (J or H ) simultaneously with Robo-AO on the Kitt Peak 2.1 m telescope and later the Maunakea University of Hawaii 2.2 m telescope. To undertake the observations, we commissioned a new infrared camera for Robo-AO that uses a low-noise high-speed SAPHIRA avalanche photodiode detector. We detected 121 companion candidates around 111 stars, of which 62 companions are physically associated based on Gaia DR2 parallaxes and proper motions, another 45 require follow-up observations to confirm physical association, and 14 are background objects. The companion separations range from 2 to 1101 au and reach contrast ratios of 7.7 mag in the nearinfrared compared to the primary. The majority of confirmed and pending candidates are stellar companions, with ∼5 being potentially substellar and requiring follow-up observations for confirmation. We also detected a 43±9 M Jup and an 81±5 M Jup companion that were previously reported. We found 34 of our targets have acceleration measurements detected using Hipparcos-Gaia proper motions. Of those, -+ 58 1412 % of the 12 stars with imaged companion candidates have significant accelerations (c > 11.8 2), while only -+ 23 6 11 % of the remaining 22 stars with no detected companion have significant accelerations. The significance of the acceleration decreases with increasing companion separation. These young accelerating low-mass stars with companions will eventually yield dynamical masses with future orbit monitoring.

show abstract

Section: Survey Yields and Expectationssupporting

confidence: 91%

Large Adaptive Optics Survey for Substellar Objects around Young, Nearby, Low-mass Stars with Robo-AO

Salama

Baranec

et al. 2021

View full text Add to dashboard Cite

show abstract

“…For brown dwarfs, objects with insufficient mass to sustain core hydrogen fusion (Kumar 1962(Kumar , 1963Hayashi & Nakano 1963), such systems provide empirical tests of evolutionary cooling models, where the combination of mass and atmospheric properties, in some cases coupled with external information on system age or composition, can be directly compared to model predictions (Dupuy et al 2009(Dupuy et al , 2014Kasper et al 2009;Konopacky et al 2010;Liu et al 2010;Burgasser et al 2012). In addition, given that a significant fraction (15-30%) of very low mass (VLM; M ≤ 0.1 M ⊙ ) stars and brown dwarfs are found in a 20 AU binary systems (e.g., Allen 2007;Burgasser et al 2007;Dupuy et al 2013;Duchêne & Kraus 2013 and references therein), the orbital properties of these systems and degree of spin-orbit alignment provide necessary constraints on brown dwarf formation mechanisms, which are still under investigation (Bate 2009(Bate , 2012Offner et al 2010;Kratter 2011;Parker & Meyer 2014).…”

Section: Introductionmentioning

confidence: 99%

The Orbit of the L Dwarf + T Dwarf Spectral Binary SDSS J080531.84+481233.0*

Burgasser

Blake

Gelino

et al. 2016

ApJ

View full text Add to dashboard Cite

SDSS J080531.84+481233.0 is a closely-separated, very-low-mass binary identified through combined-light spectroscopy and confirmed as an astrometric variable. Here we report four years of radial velocity monitoring observations of the system that reveal significant and periodic variability, confirming the binary nature of the source. We infer an orbital period of 2.02±0.03 yr, a semi-major axis of 0.76 +0.05 −0.06 AU, and an eccentricity of 0.46±0.05, consistent with the amplitude of astrometric variability and prior attempts to resolve the system. Folding in constraints based on the spectral types of the components (L4±0.7 and T5.5±1.1), corresponding effective temperatures, and brown dwarf evolutionary models, we further constrain the orbital inclination of this system to be nearly edge-on (90 • ± 19 • ), and deduce a large system mass ratio (M 2 /M 1 = 0.86 +0.10 −0.12 ), substellar components (M 1 = 0.057 +0.016 −0.014 M ⊙ , M 2 = 0.048 +0.008 −0.010 M ⊙ ), and a relatively old system age (minimum age = 4.0 +1.9 −1.2 Gyr). The measured projected rotational velocity of the primary (V rot sin i = 34.1±0.7 km s −1 ) implies that this inactive source is a rapid rotator (period 3 hr) and a viable system for testing spin-orbit alignment in very-low-mass multiples. Robust model-independent constraints on the component masses may be possible through measurement of the reflex motion of the secondary at wavelengths in which it contributes a greater proportion of the combined luminence, while the system may also be resolvable through sparse-aperature mask interferometry with adaptive optics. The combination of well-determined component atmospheric properties and masses near and/or below the hydrogen minimum mass make SDSS J0805+4812AB an important system for future tests of brown dwarf evolutionary models.

show abstract

Multiplicity of cool dwarfs

Cited by 2 publications

References 33 publications

Large Adaptive Optics Survey for Substellar Objects around Young, Nearby, Low-mass Stars with Robo-AO

Large Adaptive Optics Survey for Substellar Objects around Young, Nearby, Low-mass Stars with Robo-AO

The Orbit of the L Dwarf + T Dwarf Spectral Binary SDSS J080531.84+481233.0*

Contact Info

Product

Resources

About