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Very Low-mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. VI. A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646
Bizyaev, Dmitry; Ge, Jian; Schneider, Donald P. +34 more
We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was …
Gamma-ray burst polarization reduction induced by the Lorentz invariance violation
Chang, Zhe; Li, Xin; Lin, Hai-Nan
It has been observed that photons in the prompt emission of some gamma-ray bursts (GRBs) are highly polarized. The high polarization is used by some authors to give a strict constraint on the Lorentz invariance violation (LIV). If the Lorentz invariance is broken, the polarization vector of a photon may rotate during its propagation. The rotation …
Limb-darkening coefficients from line-blanketed non-LTE hot-star model atmospheres
Howarth, I. D.; Reeve, D. C.
We present grids of limb-darkening coefficients computed from non-local thermodynamic equilibrium (non-LTE), line-blanketed TLUSTY model atmospheres, covering effective-temperature and surface-gravity ranges of 15-55 kK and 4.75 dex (cgs) down to the effective Eddington limit, at 2×, 1×, 0.5× (Large Magellanic Cloud), 0.2× (Small Magellanic Cloud)…
Scientific considerations for future spectroscopic measurements from space of activity on the Sun
Holman, Gordon D.
High-resolution UV and X-ray spectroscopy are important to understanding the origin and evolution of magnetic energy release in the solar atmosphere, as well as the subsequent evolution of heated plasma and accelerated particles. Electromagnetic radiation is observed from plasma heated to temperatures ranging from about 10 kK to above 10 MK, from …
Searching for FUV line emission from 107 K gas in massive elliptical galaxies and galaxy clusters as a tracer of turbulent velocities
Anderson, Michael E.; Sunyaev, Rashid
Non-thermal pressure from turbulence and bulk flows is a fundamental ingredient in hot gaseous haloes, and in the intracluster medium, it will be measured through emission line kinematics with calorimeters on future X-ray spacecraft. In this paper, we present a complementary method for measuring these effects, using forbidden FUV emission lines of…
Hubble Space Telescope Constraints on the Winds and Astrospheres of Red Giant Stars
Harper, Graham M.; Wood, Brian E.; Müller, Hans-Reinhard
We report on an ultraviolet spectroscopic survey of red giants observed by the Hubble Space Telescope, focusing on spectra of the Mg II h and k lines near 2800 Å in order to study stellar chromospheric emission, winds, and astrospheric absorption. We focus on spectral types between K2 III and M5 III, a spectral type range with stars that are nonco…
On the void explanation of the Cold Spot
Martínez-González, E.; Vielva, P.; Marcos-Caballero, A. +1 more
The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe…
Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lara, L. M.; Lamy, P. +52 more
Context. Data derived from the reconstruction of the nucleus shape of comet 67P/Churyumov-Gerasimenko (67P) from images of the OSIRIS camera onboard ROSETTA show evidence that the nucleus rotates in complex mode. First, the orientation of the spin axis is not fixed in an inertial reference frame, which suggests a precessing motion around the angul…
On the origin of the ionosphere at the Moon using results from Chandrayaan-1 S band radio occultation experiment and a photochemical model
Choudhary, R. K.; Bhardwaj, Anil; Dhanya, M. B. +2 more
The origin of the Moon's ionosphere has been explored using Chandrayaan-1 radio occultation (RO) measurements and a photochemical model. The electron density near the Moon's surface, obtained on 31 July 2009 (∼300 cm-3), is compared with results from a model which includes production and recombination of 16 ions, solar wind proton charg…
The JCMT Gould Belt Survey: evidence for radiative heating and contamination in the W40 complex
White, G. J.; Marsh, K.; Ward-Thompson, D. +56 more
We present SCUBA-2 450 µm and 850 µm observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spect…