A5083165380- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Photocathodes and Microchannel Plates
- Calibration and Measurement Techniques
- Astrophysics and Cosmic Phenomena
- Molecular Spectroscopy and Structure
- Adaptive optics and wavefront sensing
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Planetary Science and Exploration
- Galaxies: Formation, Evolution, Phenomena
- Spacecraft and Cryogenic Technologies
- Atomic and Molecular Physics
- Geomagnetism and Paleomagnetism Studies
- Spectroscopy and Laser Applications
Joint Institute for Laboratory Astrophysics
2015-2024
University of Colorado Boulder
2010-2024
University of Colorado System
1978-2024
Marshall Space Flight Center
2022
Space Research Institute
2020-2021
Austrian Academy of Sciences
2020
International Space Science Institute
2017
Space Telescope Science Institute
2013
Association of Universities For Research In Astronomy
2011-2013
Laboratory for Atmospheric and Space Physics
2001-2013
view Abstract Citations (754) References (85) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Relations among stellar X-ray emission observed from Einstein, rotation and bolometric luminosity. Pallavicini, R. ; Golub, L. Rosner, Vaiana, G. S. Ayres, T. Linsky, J. The correlation between luminosities, projected rotational velocities for stars of various spectral types luminosity classes are determined. Early type (O3 to A5) have luminosities independent...
The Far Ultraviolet Spectroscopic Explorer satellite observes light in the far-ultraviolet spectral region, 905-1187 Å, with a high resolution. instrument consists of four co-aligned prime-focus telescopes and Rowland spectrographs microchannel plate detectors. Two telescope channels use Al : LiF coatings for optimum reflectivity between approximately 1000 1187 other two SiC optimized throughput 905 1105 Å. gratings are holographically ruled to correct largely astigmatism minimize scattered...
The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present design philosophy and summarize key characteristics of instrument will be interest to potential observers. For faint targets, flux F_lambda ~ 1.0E10-14 ergs/s/cm2/Angstrom, COS can achieve comparable signal noise (when compared STIS echelle modes) 1-2% observing...
Measurements of stellar mass-loss rates are used to assess how wind strength varies with coronal activity and age for solar-like stars. Mass loss generally increases activity, but we find evidence that winds suddenly weaken at a certain threshold. Very active stars often observed have polar starspots, speculate the magnetic field geometry associated these spots may be inhibiting winds. Our inferred mass-loss/age relation represents an empirical estimate history solar wind. This result is...
Collisions between the winds of solar-like stars and local interstellar medium result in a population hot hydrogen gas surrounding these stars. Absorption from this H I can be detected high-resolution Lyα spectra Hubble Space Telescope. The amount absorption used as diagnostic for stellar mass-loss rate. We present new rate measurements derived fashion four ( Eri, 61 Cyg A, 36 Oph AB, 40 Eri A). Combining with others, we study how mass loss varies activity. find that GK dwarfs, per unit...
Ground- and space-based planet searches employing radial velocity techniques transit photometry have detected thousands of planet-hosting stars in the Milky Way. The chemistry these atmospheres is controlled by shape absolute flux stellar spectral energy distribution, however, distributions relatively inactive low-mass are poorly known at present. To better understand exoplanets orbiting stars, we executed a panchromatic (X-ray to mid-IR) study 11 nearby hosting {\it Measurements Ultraviolet...
We present a comprehensive survey of CII* absorption detections toward stars within 100 pc in order to measure the distribution electron densities local interstellar medium (LISM). Using high spectral resolution observations nearby obtained by GHRS and STIS onboard Hubble Space Telescope, we identify 13 sight lines with 23 individual components, which provide density measurements, vast majority are new. employ several strategies determine more accurate CII column from saturated resonance...
Using the new Cosmic Origins Spectrograph (COS) on {\it Hubble Space Telescope (HST)}, we obtained moderate-resolution, high signal/noise ultraviolet spectra of HD 209458 and its exoplanet 209458b during transit, both orbital quadratures, secondary eclipse. We compare transit with at non-transit phases to identify spectral features due exoplanet's expanding atmosphere. find that mean flux decreased by $7.8\pm 1.3$% for C II 1334.5323\AA\ 1335.6854\AA\ lines $8.2\pm 1.4$% Si III 1206.500\AA\...
The spectral and temporal behavior of exoplanet host stars is a critical input to models the chemistry evolution planetary atmospheres. Ultraviolet photons influence atmospheric temperature profiles production potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding ultraviolet spectra M dwarfs, despite their importance predicting interpreting potentially habitable as they are obtained in coming decades....
The ultraviolet (UV) spectral energy distributions of low-mass (K- and M-type) stars play a critical role in the heating chemistry exoplanet atmospheres, but are not observationally well-constrained. Direct observations intrinsic flux Lyman alpha line (the dominant source UV photons from stars) challenging, as interstellar HI absorbs entire core for even closest stars. To address existing gap empirical constraints on K M dwarfs, MUSCLES HST Treasury Survey has obtained 11 nearby dwarfs...
We present a catalog of panchromatic spectral energy distributions (SEDs) for 7 M and 4 K dwarf stars that span X-ray to infrared wavelengths (5 {\AA} - 5.5 {\mu}m). These SEDs are composites Chandra or XMM-Newton data from 5 ~50 {\AA}, plasma emission model 100 broadband empirical estimates 1170 HST 5700 including reconstruction stellar Ly{\alpha} at 1215.67 PHOENIX spectrum 55000 {\AA}. Using these SEDs, we computed the photodissociation rates several molecules prevalent in planetary...
The Space Telescope Imaging Spectrograph (STIS) instrument was installed on the Hubble (HST) during second servicing mission, in 1997 February. Four bands cover wavelength range of 115–1000 nm, with spectral resolving powers between 26 and 200,000. Camera modes are used for target acquisition deep imaging. Correction HST's spherical aberration astigmatism is included. 115–170 nm covered by a CsI MAMA (Multianode Microchannel Array) detector 165–310 Cs2Te MAMA, each format 2048 × pixels,...
view Abstract Citations (237) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The α Centauri line of sight: D/H ratio, physical properties local interstellar gas, and measurement heated hydrogen (the "hydrogen wall") near the heliopause. Linsky, Jeffrey L. ; Wood, Brian E. authors analyze high resolution spectra nearby (1.34 pc) stars Cen A (G2 V) B (K1 V), which were obtained with GHRS on HST. observations consist echelle Mg II 2800 Å Fe 2599...
We search the Hubble Space Telescope (HST) archive for previously unanalyzed observations of stellar H I Lyα emission lines, our primary purpose being to look new detections absorption from outer heliosphere and also analogous astrospheres surrounding observed stars. The astrospheric is particular interest because it can be used study solar-like winds that are otherwise undetectable. find analyze 33 HST spectra in archive. All were taken with E140M grating Imaging Spectrograph (STIS)...
view Abstract Citations (286) References (74) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Goddard High-Resolution Spectrograph Observations of the Local Interstellar Medium and Deuterium/Hydrogen Ratio along Line Sight toward Capella Linsky, Jeffrey L. ; Brown, Alexander Gayley, Ken Diplas, Athanassios Savage, Blair D. Ayres, Thomas R. Landsman, Wayne Shore, Steven N. Heap, Sara HST observations 1216, 2600, 2800 A spectral regions are analyzed for...
On 2008 May 2, Chandra observed the X-ray spectrum of Xi Boo (G8 V+K4 V), resolving binary for first time in X-rays and allowing coronae two stars to be studied separately. With contributions A B system's total emission now observationally established (88.5% 11.5%, respectively), consideration mass loss measurements GK dwarfs various activity levels (including one Boo) leads surprising conclusion that may dominate wind from binary, with A's being very weak despite its active corona. Emission...
Analyses of spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, together from Copernicus and interstellar medium absorption profile spectrograph (IMAPS) instruments, reveal an unexplained, very wide range in observed deuterium/hydrogen (D/H) ratios for gas Galactic disk beyond Local Bubble. We argue that spatial variations depletion deuterium onto dust grains can explain these local gas-phase D/H ratios. present a variable model naturally explains constant...
view Abstract Citations (225) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Deuterium and the Local Interstellar Medium Properties for Procyon Capella Lines of Sight Linsky, Jeffrey L. ; Diplas, Athanassios Wood, Brian E. Brown, Alexander Ayres, Thomas R. Savage, Blair D. We present Goddard High-Resolution Spectrograph observations interstellar H I D Lyα lines Mg II Fe resonance formed along sight toward nearby stars (3.5 pc, l = 214°, b...
We observed the classical T Tauri star TW Hya with Space Telescope Imaging Spectrograph on board Hubble (HST) using E140M grating, from 1150 to 1700 Å, E230M 2200 2900 and Far Ultraviolet Spectroscopic Explorer 900 1180 Å. Emission in 146 Lyman-band H2 lines, representing 19 progressions, dominates spectral region 1250 1650 The total emission line flux is 1.94 × 10-12 ergs cm-2 s-1, which corresponds 1.90 10-4 L☉ at Hya's distance of 56 pc. A broad stellar Lyα photoexcites excited...
Extreme ultraviolet (EUV) radiations (10--117 nm) from host stars play important roles in the ionization, heating, and mass loss exoplanet atmospheres. Together with star's Lyman-alpha far-UV (117--170 radiation, EUV radiation photodissociates molecules, thereby changing chemistry Since stellar fluxes cannot now be measured interstellar neutral hydrogen completely obscures between 40 91.2 nm, even for nearest stars, we must estimate unobservable flux by indirect methods. New non-LTE...
We measure the temperature of warm gas at planet-forming radii in disk around classical T Tauri star (CTTS) TW Hya by modeling H2 fluorescence observed Hubble Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer spectra. Strong Lyα emission irradiates a surface within 2 AU central pumps certain excited levels H2. simulate one-dimensional plane-parallel atmosphere to estimate fluxes for 140 lines reconstruct profile incident upon The excitation can be determined...
ASTRONOMICAL SOCIETY OF THE PACIFIC Vol. 82 April 1970 No. 485 SOLAR H AND K LINES JEFFREY L. LINSKY Joint Institute for Laboratory Astrophysics of the National Bureau Standards and University Colorado EUGENE H. AVRETT Smithsonian Astrophysical Observatory Harvard College itory 22, We review our current understanding formation Ca ii resonance infi-ared triplet subordinate lines in sun view wedth observations these devdopment non-LTE line theory. descrihe low- high-spatial resolution data on...