Search Publications
Red Supergiants in the Inner Galaxy: Stellar Properties
Menten, Karl M.; Zhu, Qingfeng; Kudritzki, Rolf-Peter +4 more
Red supergiants (RSGs) are luminous cool stars detectable in disks of distant spirals. About a thousand are known in the Galaxy. Here, we analyze a sample of late-type stars recently observed by Messineo et al. in the inner Galaxy (10^\circ < l< 60^\circ ). A total of 58 targets (25% of previously known RSGs) were reported as supergiants bas…
CO Spectral Line Energy Distributions in Galactic Sources: Empirical Interpretation of Extragalactic Observations
Schilke, P.; Lis, D. C.; Bergin, E. A. +5 more
The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with Herschel/HIFI in the star-forming cores Orion S, Orion KL, Sgr B2(M), and W49N. Integrated line fluxes from these ob…
Strongly coupled dark energy with warm dark matter vs. LCDM
Bonometto, S. A.; Mezzetti, M.; Mainini, R.
Cosmologies including strongly Coupled (SC) Dark Energy (DE) and Warm dark matter (SCDEW) are based on a conformally invariant (CI) attractor solution modifying the early radiative expansion. Then, aside of radiation, a kinetic field Φ and a DM component account for a stationary fraction, ~ 1 %, of the total energy. Most SCDEW predictions are hard…
Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud
Sitko, M. L.; Marengo, M.; Chen, C. H. +4 more
We have obtained new NASA/IRTF SpeX spectra of the HR 4796A debris ring system. We find a unique red excess flux that extends out to ∼9 µm in Spitzer IRS spectra, where thermal emission from cold, ∼100 K dust from the system's ring at ∼75 au takes over. Matching imaging ring photometry, we find the excess consists of NIR reflectance from the…
A Six-planet System around the Star HD 34445
Butler, R. Paul; Vogt, Steven S.; Crane, Jeffrey D. +10 more
We present a new precision radial velocity (RV) data set that reveals a multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists of 333 precision RV observations, 56 of which were previously published and 277 of which are new data from the Keck Observatory, Magellan at Las Campanas Observatory, and the Automated Planet Finder …
Debris flow recurrence periods and multi-temporal observations of colluvial fan evolution in central Spitsbergen (Svalbard)
Hiesinger, H.; Hauber, E.; Johnsson, A. +2 more
Fan-shaped accumulations of debris flow deposits are common landforms in polar regions such as Svalbard. Although depositional processes in these environments are of high interest to climate as well as Mars-analog research, several parameters, e.g., debris flow recurrence periods, remain poorly constrained. Here, we present an investigation based …
The way to a double degenerate: ∼15-20 per cent of 1 M⊙ ≤ M ≤ 8 M⊙ stars have an M > 1 M⊙ companion
Klein, Ygal Y.; Katz, Boaz
We find that ∼15-20 per cent of A-type stars or red giants are bound with a massive companion (Msecondary > 1 M⊙) in an intermediate wide orbit (0.5 < P < 5000 yr). These massive binaries are expected to form wide-orbit, double-degenerate systems (WODDs) within ≲10 Gyr implying that ∼10 per cent of white dwarfs (WDs)…
The Panchromatic Hubble Andromeda Treasury. XVII. Examining Obscured Star Formation with Synthetic Ultraviolet Flux Maps in M31.
Bell, Eric F.; Dolphin, Andrew E.; Skillman, Evan D. +10 more
We present synthetic far- and near-ultraviolet ({FUV} and {NUV}) maps of M31, both with and without dust reddening. These maps were constructed from spatially resolved star formation histories (SFHs) derived from optical Hubble Space Telescope imaging of resolved stars, taken as part of the Panchromatic Hubble Andromeda Treasury program. We use st…
Searching for stars closely encountering with the solar system based on data from the Gaia DR1 and RAVE5 catalogues
Bobylev, V. V.; Bajkova, A. T.
We have searched for the stars that either encountered in the past or will encounter in the future with the Solar system closer than 2 pc. For this purpose, we took more than 216 000 stars with the measured proper motions and trigonometric parallaxes from the Gaia DR1 catalogue and their radial velocities from the RAVE5 catalogue. We have found se…
Spectral and time series analyses of the Seyfert 1 AGN: Zw 229.015
Rakshit, Suvendu; Adegoke, Oluwashina; Mukhopadhyay, Banibrata
We analyse the spectra of the archival XMM-Newton data of the Seyfert 1 AGN Zw 229.015 in the energy range 0.3-10.0 keV. When fitted with a simple power law, the spectrum shows signatures of weak soft excess below 1.0 keV. We find that both thermal Comptonization and relativistically blurred reflection models provide the most acceptable spectral f…