A Search for Substellar Companions to the Two Nearest Brown Dwarf Systems

Melso, Nicole; Kaldon, K.; Luhman, K. L.

doi:10.1088/0004-6256/150/2/62

Cited by 5 publications

(8 citation statements)

References 37 publications

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“…(i) We rule out co-moving companions down to Y dwarf spectral types in the range 1-80 AU. This result confirms the finding of Melso et al (2015), which is based on superior data for this analysis. Note that Melso et al also extended this investigation at wider separations.…”

Section: Discussionsupporting

confidence: 91%

Hubble Space Telescope astrometry of the closest brown dwarf binary system – I. Overview and improved orbit★

Bedin

Pourbaix

Apai

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Located at 2 pc, the L7.5+T0.5 dwarfs system WISE J104915.57−531906.1 (Luhman 16 AB) is the third closest system known to Earth, making it a key benchmark for detailed investigation of brown dwarf atmospheric properties, thermal evolution, multiplicity, and planet-hosting frequency. In the first study of this series -based on a multicycle Hubble Space Telescope (HST) program -we provide an overview of the project and present improved estimates of positions, proper motions, annual parallax, mass ratio, and the current best assessment of the orbital parameters of the A-B pair. Our HST observations encompass the apparent periastron of the binary at 220.5 ± 0.2 mas at epoch 2016.402. Although our data seem to be inconsistent with recent ground-based astrometric measurements, we also exclude the presence of third bodies down to Neptune masses and periods longer than a year.

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Section: Discussionsupporting

confidence: 91%

Hubble Space Telescope astrometry of the closest brown dwarf binary system – I. Overview and improved orbit★

Bedin

Pourbaix

Apai

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…We have also included all previous Spitzer observations of the object (Luhman 2014;Melso et al 2015) and two photometric monitoring campaigns with Spitzer that will be presented by T. Esplin (2016, in preparation).…”

Section: Observationsmentioning

confidence: 99%

“…The second of those observations consisted of a large map (840″×840″) rather than a single field of view of the camera. Melso et al (2015) performed a second map of the same size in 2015, corresponding to the fifth epoch overall. We have measured astrometry for WISE 0855-0714 from all epochs of [4.5] images except the two photometric monitoring campaigns.…”

Section: Spitzer Irac Imagesmentioning

confidence: 99%

“…In Table 1, we have compiled the telescopes, instruments, filters, exposure times, dates, and program identifications for our imaging of WISE 0855−0714. We have also included all previous Spitzer observations of the object Melso et al 2015) and two photometric monitoring campaigns with Spitzer that will be presented by T. Esplin (in preparation).…”

Section: Observationsmentioning

confidence: 99%

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The Spectral Energy Distribution of the Coldest Known Brown Dwarf*

Luhman

Esplin

2016

Self Cite

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WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf (∼250 K) and the fourth-closest known system to the Sun (2.2 pc). It has been previously detected only in the J band and two mid-IR bands. To better measure its spectral energy distribution (SED), we have performed deep imaging of WISE 0855-0714 in six optical and near-IR bands with Gemini Observatory, the Very Large Telescope, and the Hubble Space Telescope. Five of the bands show detections, although one detection is marginal (S/N∼3). We also have obtained two epochs of images with the Spitzer Space Telescope for use in refining the parallax of the brown dwarf. By combining astrometry from this work and previous studies, we have derived a parallax of 0.449±0.008″ (2.23 ± 0.04 pc). We have compared our photometry for WISE 0855-0714 to data for known Y dwarfs and to the predictions of three suites of models by Saumon et al. and Morley et al. that are defined by the presence or absence of clouds and nonequilibrium chemistry. Our estimates of Y − J and J − H for WISE 0855-0714 are redder than colors of other Y dwarfs, confirming a predicted reversal of near-IR colors to redder values at temperatures below 300-400 K. In color-magnitude diagrams, no single suite of models provides a clearly superior match to the sequence formed by WISE 0855-0714 and other Y dwarfs. Instead, the best-fitting model changes from one diagram to the next. Similarly, all of the models have substantial differences from the SED of WISE 0855-0714. As a result, we are currently unable to constrain the presence of clouds or nonequilibrium chemistry in its atmosphere.

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“…Not surprisingly, the first directly imaged exoplanet orbits a BD (Chauvin et al 2004(Chauvin et al , 2005 and the nearest planet was discovered with radial velocity monitoring of the M-type star (Anglada-Escudé et al 2016). Hubble Space Telescope (HST) imaging found no companions of W0855 within 0.5 AU Zapatero Osorio et al 2016) and Spitzer imaging reported none within 9-970 AU (Melso et al 2015). Unfortunately, the object is too faint for radial velocity monitoring even with the best current or near-future spectrographs.…”

Section: Introductionmentioning

confidence: 99%

A search for millimeter emission from the coldest and closest brown dwarf with ALMA

Petry

Ivanov

2020

A&A

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Context. WISE J085510.83−071442.5 (W0855) is a unique object: with Teff ≈ 250 K it is the coldest known brown dwarf (BD), located at only ≈2.2 pc form the Sun. It is extremely faint, which makes any astronomical observations difficult. However, at least one remotely similar ultra-low-mass object, the M9 dwarf TVLM 513-46546, has been shown to be a steady radio emitter at frequencies up to 95 GHz with superimposed active states where strong, pulsed emission is observed. Aims. Our goal is to determine the millimeter radio properties of W0855 with deep observations around 93 GHz (3.2 mm) in order to investigate whether radio astrometry of this object is feasible and to measure or set an upper limit on its magnetic field. Methods. We observed W0855 for 94 min at 85.1–100.9 GHz on 24 December 2019 using 44 of the Atacama Large millimeter Array (ALMA) 12 m antennas. We used the standard ALMA calibration procedure and created the final image for our analysis by accommodating the Quasar 3C 209, the brightest nearby object by far. Furthermore, we created a light curve with a 30 s time resolution to search for pulsed emission. Results. Our observations achieve a noise RMS of 7.3 μJy beam−1 for steady emission and of 88 μJy for 30 s pulses in the aggregated bandwidth (Stokes I). There is no evidence for steady or pulsed emission from the object at the time of the observation. We derive 3σ upper limits of 21.9 μJy on the steady emission and of 264 μJy on the pulsed emission of W0855 between 85 GHz and 101 GHz. Conclusions. Together with the recent non-detection of W0855 at 4–8 GHz, our constraints on the steady and pulsed emission from W0855 confirm that the object is neither radio-loud nor magnetospherically particularly active.

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A Search for Substellar Companions to the Two Nearest Brown Dwarf Systems

Cited by 5 publications

References 37 publications

Hubble Space Telescope astrometry of the closest brown dwarf binary system – I. Overview and improved orbit★

Hubble Space Telescope astrometry of the closest brown dwarf binary system – I. Overview and improved orbit★

The Spectral Energy Distribution of the Coldest Known Brown Dwarf*

A search for millimeter emission from the coldest and closest brown dwarf with ALMA

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