Dynamical masses of <i>M</i>-dwarf binaries in young moving groups

Janson, Markus; Durkan, S.; Bonnefoy, M.; Rodet, L.; Köhler, Rainer H.; Lacour, S.; Brandner, W.; Henning, Thomas; Girard, J.

doi:10.1051/0004-6361/201833375

Cited by 8 publications

(9 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because of their proximity and youth, YMGs have become a rich resource to study a broad range of topics: the evolution of stellar dynamos and activity (e.g., Shkolnik & Barman 2014;Ansdell et al 2015); dynamical masses of intermediate-age stars (e.g., Close et al 2005;Montet et al 2015;Nielsen et al 2016;Janson et al 2018); the structure and evolution of debris disks (e.g., Wyatt et al 2014); young brown dwarfs and freefloating planetary-mass objects (Liu et al 2013;Allers & Liu 2013;Gagné et al 2014;Aller et al 2016;Liu et al 2016;Faherty et al 2016); multiplicity at young ages (Shan et al 2017;Janson et al 2017;Best et al 2017); and the initial mass function of sparse clusters (Gagné et al 2017). Members of YMGs have also become favored targets for direct imaging searches for exoplanets (e.g., Biller et al 2013;Brandt et al 2014;Bowler et al 2015a;Chauvin et al 2015) and, as a result, many of the known directly imaged planets and planetary-mass companions orbit members of these associations (e.g., 2M1207-3932 b, Chauvin et al 2004; HR 8799 bcde, Marois et al 2008;β Pic b, Lagrange et al 2010, 51 Eri b, Macintosh et al 2015GU Psc b, Naud et al 2014;2M2236+4751 b, Bowler et al 2017.…”

Section: Introductionmentioning

confidence: 99%

The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-rich Stars in the Solar Neighborhood

Bowler

Hinkley

Ziegler

et al. 2019

ApJ

View full text Add to dashboard Cite

Young stars in the solar neighborhood serve as nearby probes of stellar evolution and represent promising targets to directly image self-luminous giant planets. We have carried out an all-sky search for late-type (≈K7-M5) stars within 100 pc selected primarily on the basis of activity indicators from GALEX and ROSAT . Approximately two thousand active and potentially young stars are identified, over 600 of which we have followed up with low-resolution optical spectroscopy and over 1000 with diffraction-limited imaging using Robo-AO at the Palomar 1.5-m telescope. Strong lithium is present in 58 stars, implying ages spanning ≈10-200 Myr. Most of these lithium-rich stars are new or previously known members of young moving groups including TWA, β Pic, Tuc-Hor, Carina, Columba, Argus, AB Dor, Upper Centaurus Lupus, and Lower Centaurus Crux; the rest appear to be young low-mass stars without connections to established kinematic groups. Over 200 close binaries are identified down to 0. 2 -the vast majority of which are new -and will be valuable for dynamical mass measurements of young stars with continued orbit monitoring in the future.

show abstract

Section: Introductionmentioning

confidence: 99%

The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-rich Stars in the Solar Neighborhood

Bowler

Hinkley

Ziegler

et al. 2019

ApJ

View full text Add to dashboard Cite

show abstract

“…The high-resolution of ZIMPOL is of course useful for accurate (∼1 mas) relative astrometry between the bright central star and faint companions. For the AB Dor B binary it was possible to measure separations with a precision of ±1 mas (Janson et al 2018), and with the new, accurate astrometric calibration of ZIMPOL (Ginski et al in prep. ) even more accurate measurements should be achievable for easy targets.…”

Section: Astrometrymentioning

confidence: 99%

“…The high resolution of ZIMPOL was successfully used to separate close binaries, with separations less than 0.1 , for example 45 mas for R Aqr (Schmid et al 2017), or 38 mas for AB Dor B (Janson et al 2018), or for resolving structures on objects with diameters smaller than 0.1 , for example on nearby red gi-ant stars (Kervella et al 2016;Khouri et al 2016;Ohnaka et al 2016) or asteroids (Vernazza et al 2018).…”

Section: High-resolution Imagingmentioning

confidence: 99%

SPHERE: the exoplanet imager for the Very Large Telescope

Beuzit

Vigan

Mouillet

et al. 2019

A&A

493

169

View full text Add to dashboard Cite

Observations of circumstellar environments that look for the direct signal of exoplanets and the scattered light from disks have significant instrumental implications. In the past 15 years, major developments in adaptive optics, coronagraphy, optical manufacturing, wavefront sensing, and data processing, together with a consistent global system analysis have brought about a new generation of high-contrast imagers and spectrographs on large ground-based telescopes with much better performance. One of the most productive imagers is the Spectro-Polarimetic High contrast imager for Exoplanets REsearch (SPHERE), which was designed and built for the ESO Very Large Telescope (VLT) in Chile. SPHERE includes an extreme adaptive optics system, a highly stable common path interface, several types of coronagraphs, and three science instruments. Two of them, the Integral Field Spectrograph (IFS) and the Infra-Red Dual-band Imager and Spectrograph (IRDIS), were designed to efficiently cover the near-infrared (NIR) range in a single observation for an efficient search of young planets. The third instrument, ZIMPOL, was designed for visible (VIS) polarimetric observation to look for the reflected light of exoplanets and the light scattered by debris disks. These three scientific instruments enable the study of circumstellar environments at unprecedented angular resolution, both in the visible and the near-infrared. In this work, we thoroughly present SPHERE and its on-sky performance after four years of operations at the VLT.

show abstract

“…For very close binary stars, the ≈ 20 mas spatial resolution of SPHERE/ZIMPOL is of course very useful for orbit determinations and the photometry of the individual components (e.g., Janson et al 2018). A particular niche for the visual ZIMPOL instrument, when compared to near-IR AO instruments, are faint, hot companions to red stars, like white dwarfs companions to Ba-star, or Hα emitting active components to M-giants like the symbiotic system R Aqr shown in Fig.…”

Section: Close Binary Starsmentioning

confidence: 99%

SPHERE / ZIMPOL high resolution polarimetric imager. I. System overview, PSF parameters, coronagraphy, and polarimetry

Schmid,

Bazzon,

Roelfsema

et al. 2018

Preprint

View full text Add to dashboard Cite

Context. The SPHERE "planet finder" is an extreme adaptive optics (AO) instrument for high resolution and high contrast observations at the Very Large Telescope (VLT). We describe the Zurich Imaging Polarimeter (ZIMPOL), the visual focal plane subsystem of SPHERE, which pushes the limits of current AO systems to shorter wavelengths, higher spatial resolution, and much improved polarimetric performance. Aims. We present a detailed characterization of SPHERE/ZIMPOL which should be useful for an optimal planning of observations and for improving the data reduction and calibration. We aim to provide new benchmarks for the performance of high contrast instruments, in particular for polarimetric differential imaging. Methods. We have analyzed SPHERE/ZIMPOL point spread functions (PSFs) and measure the normalized peak surface brightness, the encircled energy, and the full width half maximum (FWHM) for different wavelengths, atmospheric conditions, star brightness, and instrument modes. Coronagraphic images are described and the peak flux attenuation and the off-axis flux transmission are determined. Simultaneous images of the coronagraphic focal plane and the pupil plane are analyzed and the suppression of the diffraction rings by the pupil stop is investigated. We compared the performance at small separation for different coronagraphs with tests for the binary α Hyi with a separation of 92 mas and a contrast of ∆m ≈ 6 m . For the polarimetric mode we made the instrument calibrations using zero polarization and high polarization standard stars and here we give a recipe for the absolute calibration of polarimetric data. The data show a small (< 1 mas) but disturbing differential polarimetric beam shifts, which can be explained as Goos-Hähnchen shifts from the inclined mirrors, and we discuss how to correct this effect. The polarimetric sensitivity is investigated with non-coronagraphic and deep, coronagraphic observations of the dust scattering around the symbiotic Mira variable R Aqr. Results. SPHERE/ZIMPOL reaches routinely an angular resolution (FWHM) of 22−28 mas, and a normalized peak surface brightness of SB 0 − m star ≈ −6.5 m arcsec −2 for the V-, R-and I-band. The AO performance is worse for mediocre ∼ > 1.0 seeing conditions, faint stars m R ∼ > 9 m , or in the presence of the "low wind" effect (telescope seeing). The coronagraphs are effective in attenuating the PSF peak by factors of > 100, and the suppression of the diffracted light improves the contrast performance by a factor of approximately two in the separation range 0.06 −0.20 . The polarimetric sensitivity is ∆p < 0.01 % and the polarization zero point can be calibrated to better than ∆p ≈ 0.1 %. The contrast limits for differential polarimetric imaging for the 400 s I-band data of R Aqr at a separation of ρ = 0.86 are for the surface brightness contrast SB pol (ρ) − m star ≈ 8 m arcsec −2 and for the point source contrast m pol (ρ) − m star ≈ 15 m and much lower limits are achievable with deeper observations. Conclusions. SPHERE/ZIMPOL achieves imagi...

show abstract

Dynamical masses of M-dwarf binaries in young moving groups

Cited by 8 publications

References 51 publications

The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-rich Stars in the Solar Neighborhood

The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-rich Stars in the Solar Neighborhood

SPHERE: the exoplanet imager for the Very Large Telescope

SPHERE / ZIMPOL high resolution polarimetric imager. I. System overview, PSF parameters, coronagraphy, and polarimetry

Contact Info

Product

Resources

About