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Related papers: JWST Resolves CIA Features in White Dwarfs

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White dwarfs whose atmospheres are polluted by terrestrial-like planetary debris have become a powerful and unique tool to study evolved planetary systems. This paper presents results for an unbiased Spitzer IRAC search for circumstellar…

Earth and Planetary Astrophysics · Physics 2015-03-20 M. Rocchetto , J. Farihi , B. T. Gaensicke , C. Bergfors

Some hot DA white dwarfs have circumstellar high ion absorption features in their spectra, in addition to those originating in the photosphere. In many cases, the line profiles of these absorbing components are unresolved. Given the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Nathan J. Dickinson , Martin A. Barstow , Barry Y. Welsh

We present volume-averaged neutral hydrogen fractions $x_{\rm \HI}$ and ionized bubble radii $R_{\rm b}$ measured with Ly$\alpha$ damping wing absorption of galaxies at the epoch of reionization. We combine JWST/NIRSpec spectra taken by…

Astrophysics of Galaxies · Physics 2024-06-14 Hiroya Umeda , Masami Ouchi , Kimihiko Nakajima , Yuichi Harikane , Yoshiaki Ono , Yi Xu , Yuki Isobe , Yechi Zhang

We present deep H$\alpha$ imaging of three nearby dwarf galaxies, carefully selected to optimize observations with the Maryland-Magellan Tunable Filter (MMTF) on the Magellan 6.5m telescope. An effective bandpass of $\sim$13\AA\ is used,…

Astrophysics of Galaxies · Physics 2016-02-17 Janice C. Lee , Sylvain Veilleux , Michael McDonald , Bryan Hilbert

We present a detailed spectroscopic analysis of the hot DA white dwarf G191-B2B, using the best signal to noise, high resolution near and far UV spectrum obtained to date. This is constructed from co-added \textit{HST} STIS E140H, E230H,…

Solar and Stellar Astrophysics · Physics 2015-06-17 Simon P. Preval , Martin A. Barstow , Jay B. Holberg , Nathan J. Dickinson

We present a series of systematic abundance measurements for 89 hydrogen atmosphere (DA-type) white dwarfs with temperatures spanning 16000-77000K drawn from the FUSE spectral archive. This is the largest study to date of white dwarfs where…

Solar and Stellar Astrophysics · Physics 2015-06-18 M. A. Barstow , J. K. Barstow , S. L. Casewell , J. B. Holberg , I. Hubeny

White dwarfs (WDs) with carbon absorption features in their optical spectra are known as DQ WDs. The subclass of peculiar DQ WDs are cool objects (T_eff<6000 K) which show molecular absorption bands that have centroid wavelengths ~100-300…

Astrophysics · Physics 2009-11-13 Patrick B. Hall , Aaron J. Maxwell

We report a Spitzer/IRAC search for infrared excesses around white dwarfs, including 14 newly-observed targets and 16 unpublished archived stars. We find a substantial infrared excess around two warm white dwarfs --- J220934.84+122336.5 and…

Earth and Planetary Astrophysics · Physics 2015-05-30 S. Xu , M. Jura

SIMP-0136 is a T2.5 brown dwarf whose young age ($200\pm50$~Myr) and low mass ($15\pm3$~M$_{\rm Jup}$) make it an ideal analogue for the directly imaged exoplanet population. With a 2.4 hour period, it is known to be variable in both the…

We present the serendipitous discovery of a late T-type brown dwarf candidate in JWST NIRCam observations of the Early Release Science Abell 2744 parallel field. The discovery was enabled by the sensitivity of JWST at 4~$\mu$m wavelengths…

We present an atmospheric retrieval analysis of HST/WFC3/G141 spectroscopic phase curve observations of two brown dwarfs, WD-0137B and EPIC-2122B, in ultra-short period orbits around white dwarf hosts. These systems are analogous to hot and…

Solar and Stellar Astrophysics · Physics 2024-04-26 Joshua D. Lothringer , Yifan Zhou , Daniel Apai , Xianyu Tan , Vivien Parmentier , Sarah L. Casewell

Direct mid-infrared signatures of silicate clouds in substellar atmospheres were first detected in Spitzer observations of brown dwarfs, although their existence was previously inferred from near-infrared spectra. With JWST's Mid-Infrared…

Earth and Planetary Astrophysics · Physics 2024-08-14 Sarah E. Moran , Mark S. Marley , Samuel D. Crossley

We present 1-5um spectroscopy of the coldest known brown dwarf, WISE J085510.83-071442.5 (WISE 0855), performed with the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST). NIRSpec has dramatically improved…

Solar and Stellar Astrophysics · Physics 2023-11-30 K. L. Luhman , P. Tremblin , C. Alves de Oliveira , S. M. Birkmann , I. Baraffe , G. Chabrier , E. Manjavacas , R. J. Parker , J. Valenti

Ultra-fast outflows (UFOs) are thought to be a driving mechanism of large-scale winds driven by active galactic nuclei, which cause significant galactic feedback through quenching star formation and regulating supermassive black hole…

Bayesian atmospheric retrieval tools can place constraints on the properties of brown dwarfs and hot Jupiters atmospheres. To fully exploit these methods, high signal-to-noise spectral libraries with well-understood uncertainties are…

The MIRI Excess Around Degenerates (MEAD) Survey is a cycle 2 JWST program designed to image nearby white dwarfs with MIRI at 10 and 15 microns. This survey targeted 56 white dwarfs within 25 pc to search for mid-infrared excesses, flux…

Most brown dwarfs have atmospheres with temperatures cold enough to form clouds. A variety of materials likely condense, including refractory metal oxides and silicates; the precise compositions and crystal structures of predicted cloud…

Solar and Stellar Astrophysics · Physics 2021-11-03 Jessica L. Luna , Caroline V. Morley

We present detections of the near-infrared thermal emission of three hot Jupiters and one brown-dwarf using the Wide-field Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT). These include Ks-band secondary eclipse…

We report the discovery of a further line of sight allowing detection of HeII Ly alpha absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ~ 3 quasars selected from the Hamburg Quasar Surveys yielded one detection…

Astrophysics · Physics 2016-08-30 D. Reimers , C. Fechner , H. -J. Hagen , P. Jakobsen , D. Tytler , D. Kirkman

By combining the JWST/NIRCam JADES and CEERS extragalactic datasets, we have uncovered a sample of twenty-one T and Y brown dwarf candidates at best-fit distances between 0.1 - 4.2 kpc. These sources were selected by targeting the blue…

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