Search Publications
Galactic Rotation and the Oort Constants in the Solar Vicinity
Zhao, Gang; Li, Chengdong; Yang, Chengqun
Gaia DR2 data are used to calculate the Oort constants and derive the Galactic rotational properties in this work. We choose the solar vicinity stars with a “clean” sample within 500 pc. The Oort constants are then fitted through the relation between the proper motions as a function of Galactic longitude l. A maximum likelihood method is adopted t…
Multi-scale analysis of the Monoceros OB 1 star-forming region. II. Colliding filaments in the Monoceros OB1 molecular cloud
Sanhueza, Patricio; Soam, Archana; Doi, Yasuo +24 more
Context. We started a multi-scale analysis of star formation in G202.3+2.5, an intertwined filamentary sub-region of the Monoceros OB1 molecular complex, in order to provide observational constraints on current theories and models that attempt to explain star formation globally. In the first paper (Paper I), we examined the distributions of dense …
Spectral and Timing Analysis of the Accretion-powered Pulsar 4U 1626-67 Observed with Suzaku and NuSTAR
Enoto, Teruaki; Chakrabarty, Deepto; Terada, Yukikatsu +13 more
We present an analysis of the spectral shape and pulse profile of the accretion-powered pulsar 4U 1626-67 observed with Suzaku and Nuclear Spectroscopic Telescope Array (NuSTAR) during a spin-up state. The pulsar, which experienced a torque reversal to spin-up in 2008, has a spin period of ∼7.7 s. Comparing the phase-averaged spectra obtained with…
Lyα in the GJ 1132 System: Stellar Emission and Planetary Atmospheric Evolution
Charbonneau, David; Kempton, Eliza M. -R.; Newton, Elisabeth +6 more
GJ 1132b, which orbits an M dwarf, is one of the few known Earth-sized planets, and at 12 pc away it is one of the closest known transiting planets. Receiving roughly 19× Earth’s insolation, this planet is too hot to be habitable but can inform us about the volatile content of rocky planet atmospheres around cool stars. Using Hubble Space Telescop…
Kronoseismology III: Waves in Saturn's inner C ring
Nicholson, Philip D.; French, Richard G.; McGhee-French, Colleen A. +1 more
We investigate waves driven in Saturn's rings by planetary normal modes, concentrating on the previously unexplored inner C ring. In this region, the known waves all have exceptionally short wavelengths, which has proven problematic for previous studies that depended on the accurate estimate of wave phases for wave identification. However, detaile…
Distances to Galactic OB Stars: Photometry versus Parallax
Shull, J. Michael; Danforth, Charles W.
For application to surveys of interstellar matter and Galactic structure, we compute new spectrophotometric distances to 139 OB stars frequently used as background targets for UV spectroscopy. Many of these stars have updated spectral types and digital photometry with reddening corrections from the Galactic O-Star (GOS) spectroscopic survey. We co…
On the size of the CO-depletion radius in the IRDC G351.77-0.51
Menten, K. M.; Schisano, E.; Leurini, S. +5 more
An estimate of the degree of CO-depletion (fD) provides information on the physical conditions occurring in the innermost and densest regions of molecular clouds. A key parameter in these studies is the size of the depletion radius, i.e. the radius within which the C-bearing species, and in particular CO, are largely frozen on to dust g…
Exploring the R CrA environment with SPHERE. Discovery of a new stellar companion
Lodato, G.; Barbieri, M.; Henning, T. +39 more
Aims: R Coronae Australis (R CrA) is the brightest star of the Coronet nebula of the Corona Australis (CrA) star forming region. This star is very red in color, probably due to dust absorption, and is strongly variable. High-contrast instruments allow for an unprecedented direct exploration of the immediate circumstellar environment of this s…
On the Origin of Solar Torsional Oscillations and Extended Solar Cycle
Kosovichev, A. G.; Pipin, V. V.
We present a nonlinear mean-field model of the solar interior dynamics and dynamo, which reproduces the observed cyclic variations of the global magnetic field of the Sun, as well as the differential rotation and meridional circulation. Using this model, we explain, for the first time, the extended 22 yr pattern of the solar torsional oscillations…
Which Photospheric Characteristics Are Most Relevant to Active-Region Coronal Mass Ejections?
Guerra, Jordan A.; Park, Sung-Hong; Bloomfield, D. Shaun +2 more
We investigate the relation between characteristics of coronal mass ejections and parameterizations of the eruptive capability of solar active regions widely used in solar flare-prediction schemes. These parameters, some of which are explored for the first time, are properties related to topological features, namely, magnetic polarity-inversion li…