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Debris discs around main sequence stars have been extensively characterised from infrared to millimetre wavelengths through imaging, spectroscopic, and total intensity (scattered light and/or thermal emission) measurements. Polarimetric…

Earth and Planetary Astrophysics · Physics 2023-04-12 Jonathan P. Marshall , Daniel V. Cotton , Kimberly Bott , Jeremy Bailey , Lucyna Kedziora-Chudczer , Emma L. Brown

Many white dwarfs host disks of dust produced by disintegrating planetesimals and revealed by infrared excesses. The disk around G29-38 was the first to be discovered and is now well-observed, yet we lack a cohesive picture of its geometry…

Earth and Planetary Astrophysics · Physics 2022-11-30 Nicholas P. Ballering , Colette I. Levens , Kate Y. L. Su , L. Ilsedore Cleeves

Debris discs are typically revealed through excess emission at infrared wavelengths. Most discs exhibit excess at mid- and far-infrared wavelengths, analogous to the solar system's Asteroid and Edgeworth-Kuiper belts. Recently, stars with…

Earth and Planetary Astrophysics · Physics 2016-07-20 J. P. Marshall , D. V. Cotton , K. Bott , S. Ertel , G. M. Kennedy , M. C. Wyatt , C. del Burgo , O. Absil , J. Bailey , L. Kedziora-Chudczer

We measured mid-infrared polarization of protoplanetary discs to gain new insight into their magnetic fields. Using CanariCam at the 10.4 m Gran Telescopio Canarias, we detected linear polarization at 8.7, 10.3, and 12.5 $\mu$m from discs…

Earth and Planetary Astrophysics · Physics 2017-11-16 Dan Li , Charles M. Telesco , Han Zhang , Christopher M. Wright , Eric Pantin , Peter J. Barnes , Chris Packham

We present linear polarization measurements of nearby FGK dwarfs to parts-per-million (ppm) precision. Before making any allowance for interstellar polarization, we found that the active stars within the sample have a mean polarization of…

We report on sensitive 21cm and 11cm polarization surveys of the Galactic plane carried out with the Effelsberg 100-m telescope at arcmin angular resolution and some related work. Highly structured polarized emission is seen along the…

Astrophysics · Physics 2014-10-13 W. Reich , E. Fuerst , P. Reich , R. Wielebinski , M. Wolleben

Young giant planets and brown dwarf companions emit near-infrared radiation that can be linearly polarized up to several percent. This polarization can reveal the presence of a circumsubstellar accretion disk, rotation-induced oblateness of…

ALMA observations revealed recently polarised radiation of several protoplanetary disks in the (sub-)millimetre wavelength range. Besides self-scattering of large particles, thermal emission by elongated grains is a potential source for the…

Earth and Planetary Astrophysics · Physics 2019-07-10 Florian Kirchschlager , Gesa H. -M. Bertrang , Mario Flock

We report observations of the linear polarisation of a sample of 50 nearby southern bright stars measured to a median sensitivity of $\sim$4.4 $\times 10^{-6}$. We find larger polarisations and more highly polarised stars than in the…

Solar and Stellar Astrophysics · Physics 2017-03-29 Daniel V. Cotton , Jeremy Bailey , Lucyna Kedziora-Chudczer , Kimberly Bott , P. W. Lucas , J. H. Hough , Jonathan P. Marshall

More than 36 years have passed since the discovery of the infrared excess from circumstellar dust orbiting the white dwarf G29-38, which at 17.5 pc it is the nearest and brightest of its class. The precise morphology of the orbiting dust…

Using the Submillimeter Array, we have made the first high angular resolution measurements of the linear polarization of Sagittarius A* at submillimeter wavelengths, and the first detection of intra-day variability in its linear…

Astrophysics · Physics 2009-11-13 D. P. Marrone , J. M. Moran , J. -H. Zhao , R. Rao

We report observations of the linear polarization of a sample of 49 nearby bright stars measured to sensitivities of between ~1 and 4 x 10^-6. The majority of stars in the sample show measurable polarization, but most polarizations are…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jeremy Bailey , P. W. Lucas , J. H. Hough

We present high-contrast angular differential imaging (ADI) observations of the debris disk around HD 32297 in H-band, as well as the first polarimetric images for this system in polarized differential imaging (PDI) mode with Subaru/HICIAO.…

We present on-sky polarimetric observations with the Gemini Planet Imager (GPI) obtained at straight Cassegrain focus on the Gemini South 8-m telescope. Observations of polarimetric calibrator stars, ranging from nearly unpolarized to…

Many known exoplanets harbor clouds, which lead to degeneracies in spectroscopic models between particle composition and size. Polarimetry, however, provides independent assessment. Here we report the $7.2 \sigma$ discovery of linearly…

Earth and Planetary Astrophysics · Physics 2025-09-24 Sloane J. Wiktorowicz , Pushkar Kopparla , Jiazheng Li , Yuk L. Yung

Debris disks give us the unique opportunity to probe the properties of small $\mu$m-sized particles, allowing us to peer into the constituents of their parent bodies, young analogs of comets and asteroids of our solar system. In the past,…

Earth and Planetary Astrophysics · Physics 2024-06-06 Johan Olofsson , Philippe Thébault , Amelia Bayo , Thomas Henning , Julien Milli

(Abridged). We report on the linear polarimetric observations in the Johnson I filter of 44 M6-L7.5 ultracool dwarfs (2800-1400 K). Eleven (10 L and 1 M) dwarfs appear to have significant linear polarization (P = 0.2-2.5%). We have compared…

Astrophysics · Physics 2009-11-10 M. R. Zapatero Osorio , J. A. Caballero , V. J. S. Bejar

Ultra-cool dwarfs of the L spectral type (Teff=1400-2200K) are known to have dusty atmospheres. Asymmetries of the dwarf surface may arise from rotationally-induced flattening and dust-cloud coverage, and may result in non-zero linear…

Solar and Stellar Astrophysics · Physics 2015-05-13 B. Goldman , J. Pitann , M. R. Zapatero Osorio , C. A. L. Bailer-Jones , V. J. S. Bejar , J. A. Caballero , Th. Henning

Aims.Recent studies have detected linear polarization in L dwarfs in the optical I band. Theoretical models have been developed to explain this polarization. These models predict higher polarization at shorter wavelengths. We discuss the…

Solar and Stellar Astrophysics · Physics 2015-05-14 R. Tata , E. L. Martin , S. Sengupta , N. Phan-Bao , M. R. Zapatero Osorio , H. Bouy
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