Search Publications
Missions
Journals
Publication Years
Observations of counter-propagating Alfvénic and compressive fluctuations in the chromosphere
He, Jian-Sen; Liu, Zi-Xu; Yan, Li-Mei
Recent observations have found that chromospheric spicules behave like Alfvénic fluctuations. Low-frequency Alfvén waves are predicted to partially reflect in the transition region that has a gradient in the Alfvén speed, thereby producing inward Alfvén waves, which may interact nonlinearly with outward Alfvén waves to generate Alfvénic turbulence…
The Optical and Infrared Photometric Evolution of the Recent Stellar Merger, V1309 Sco
Laine, Seppo; Wahlgren, Glenn M.; Barway, Sudhanshu +7 more
Nova Sco 2008 was recently shown to have resulted from the merger of the two stars in the contact binary V1309 Sco. This is the first stellar merger ever observed between two convective stars. We present archival data, new infrared photometry, and Hubble Space Telescope WFC3 imaging of V1309 Sco. Spitzer observations show that it had a large infra…
Search for Higgs Shifts in White Dwarfs
Onofrio, Roberto; Wegner, Gary A.
We report on a search for differential shifts between electronic and vibronic transitions in carbon-rich white dwarfs BPM 27606 and Procyon B. The absence of differential shifts within the spectral resolution and taking into account systematic effects such as space motion and pressure shifts allows us to set the first upper bound of astrophysical …
The Vela Pulsar with an Active Fallback Disk
Ginski, Christian; Werner, Klaus; Neuhäuser, Ralph +4 more
Fallback disks are expected to form around young neutron stars. The presence of these disks can be revealed by their blackbody spectrum in the infrared, optical, and UV bands. We present a re-reduction of the archival optical and infrared data of the Vela pulsar, together with the existing infrared and UV spectrum of Vela, and model their unpulsed…
Herschel, Spitzer and Magellan infrared observations of the star-forming region RCW 121 (IRAS 17149-3916)
Roth, M.; Elia, D.; Gómez, M. +4 more
We present new deep near-infrared broad- and narrow-band imaging and low-resolution spectroscopy of the star formation region RCW 121 (IRAS 17149-3916) which we analyse in combination with Herschel (70, 160, 250, 350 and 500 µm) and Spitzer (3.6, 4.5, 5.8 and 8 µm) images. The near-infrared photometry reveals the presence of a stellar …
Tracing CNO exposed layers in the Algol-type binary system u Her
Southworth, J.; Pavlovski, K.; Dervişoğlu, A. +1 more
The chemical composition of stellar photospheres in mass-transferring binary systems is a precious diagnostic of the nucleosynthesis processes that occur deep within stars, and preserves information on the components' history. The binary system u Her belongs to a group of hot Algols with both components being B stars. We have isolated the individu…
Chasing the Identification of ASCA Galactic Objects (ChIcAGO): An X-Ray Survey of Unidentified Sources in the Galactic Plane. I. Source Sample and Initial Results
Drake, Jeremy J.; Chakrabarty, Deepto; Lee, Julia C. +18 more
We present the Chasing the Identification of ASCA Galactic Objects (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the Fx ~ 10-13
Helioseismic measurements in the solar envelope using group velocities of surface waves
Vorontsov, S. V.; Baturin, V. A.; Ayukov, S. V. +1 more
At intermediate- and high-degree l, solar p and f modes can be considered as surface waves. Using variational principle, we derive an integral expression for the group velocities of the surface waves in terms of adiabatic eigenfunctions of normal modes, and address the benefits of using group-velocity measurements as a supplementary diagnostic too…
Imaging the circumstellar environment of the young T Tauri star SU Aurigae
Jeffers, S. V.; Min, M.; Canovas, H. +2 more
The circumstellar environments of classical T Tauri stars are challenging to directly image because of their high star-to-disk contrast ratio. One method to overcome this is by using imaging polarimetry where scattered and consequently polarised starlight from the star's circumstellar disk can be separated from the unpolarised light of the central…
Herschel observations of gas and dust in comet C/2006 W3 (Christensen) at 5 AU from the Sun
de Graauw, Th.; Lara, L. M.; Küppers, M. +19 more
Context. Cometary activity at large heliocentric distances is thought to be driven by outgassing of molecular species more volatile than water that are present in the nucleus. The long-period comet C/2006 W3 (Christensen) was an exceptional target for a detailed study of its distant gaseous and dust activity.
Aims: We aimed to measure the H