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AKARI Observations of Brown Dwarfs. III. CO, CO2, and CH4 Fundamental Bands and Physical Parameters
Yamamura, I.; Sorahana, S.
We investigate variations in the strengths of three molecular bands, CH4 at 3.3 µm, CO at 4.6 µm, and CO2 at 4.2 µm, in 16 brown dwarf spectra obtained by AKARI. Spectral features are examined along the sequence of source classes from L1 to T8. We find that the CH4 3.3 µm band is present in …
The Panchromatic Hubble Andromeda Treasury. I. Bright UV Stars in the Bulge of M31
Bell, Eric F.; Skillman, Evan D.; Williams, Benjamin F. +20 more
As part of the Panchromatic Hubble Andromeda Treasury multi-cycle program, we observed a 12' × 6farcm5 area of the bulge of M31 with the WFC3/UVIS filters F275W and F336W. From these data we have assembled a sample of ~4000 UV-bright, old stars, vastly larger than previously available. We use updated Padova stellar evolutionary tracks to classify …
Germanium, Arsenic, and Selenium Abundances in Metal-poor Stars
Roederer, Ian U.
The elements germanium (Ge, Z = 32), arsenic (As, Z = 33), and selenium (Se, Z = 34) span the transition from charged-particle or explosive synthesis of the iron-group elements to neutron-capture synthesis of heavier elements. Among these three elements, only the chemical evolution of germanium has been studied previously. Here we use archive obse…
From X-Ray Dips to Eclipse: Witnessing Disk Reformation in the Recurrent Nova U Sco
Talavera, A.; Ness, J. -U.; Hernanz, M. +9 more
The tenth recorded outburst of the recurrent eclipsing nova U Sco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after the outburst. Two full passages of the companion in front of the nova ejecta were observed, as was the reformation of the accretion disk. On day 22.9, we observed smooth eclipses in UV an…
Trajectories and Distribution of Interstellar Dust Grains in the Heliosphere
Slavin, Jonathan D.; Reach, William T.; Müller, Hans-Reinhard +4 more
The solar wind carves a bubble in the surrounding interstellar medium (ISM) known as the heliosphere. Charged interstellar dust grains (ISDG) encountering the heliosphere may be diverted around the heliopause or penetrate it depending on their charge-to-mass ratio. We present new calculations of trajectories of ISDG in the heliosphere, and the dus…
X-Ray and Optical Observations of A 0535+26
Guiriec, S.; Coe, M. J.; McBride, V. A. +13 more
We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A 0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since ~1978) and discussed in terms of the neutron-star-Be-disk interaction. The B…
On the Link between Associated Mg II Absorbers and Star Formation in Quasar Hosts
Shen, Yue; Ménard, Brice
A few percent of quasars show strong associated Mg II absorption, with velocities (v off) lying within a few thousand km s-1 from the quasar systemic redshift. These associated absorption line (AAL) systems are usually interpreted as absorbers that are either intrinsic to the quasar and its host, or arising from external gala…
Suzaku Observation of the Black Hole Candidate Maxi J1836-194 in a Hard/Intermediate Spectral State
Fabian, A. C.; Miller, J. M.; Reis, R. C. +2 more
We report on a Suzaku observation of the newly discovered X-ray binary MAXI J1836-194. The source is found to be in the hard/intermediate spectral state and displays a clear and strong relativistically broadened iron emission line. We fit the spectra with a variety of phenomenological, as well as physically motivated disk reflection models, and fi…
High-contrast Near-infrared Polarization Imaging of MWC480
Kuzuhara, M.; Tamura, M.; Ishii, M. +52 more
One of the key predictions of modeling from the IR excess of Herbig Ae stars is that for protoplanetary disks, where significant grain growth and settling has occurred, the dust disk has flattened to the point that it can be partially or largely shadowed by the innermost material at or near the dust sublimation radius. When the self-shadowing has …
Detection of the Second r-process Peak Element Tellurium in Metal-poor Stars
Beers, Timothy C.; Roederer, Ian U.; Frebel, Anna +6 more
Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, BD +17 3248, HD 108317, and HD 128279. Tellurium (Te, Z = 52) is found at the second r-process peak (A ≈ 130) associated …