234 Hits in 7.5 sec

Optical and X-ray transients from planet-star mergers

B. D. Metzger, D. Giannios, D. S. Spiegel
2012 Monthly notices of the Royal Astronomical Society  
For rho_p/rho_star < 1, mass transfer is stable, resulting the planet being accreted on a relatively slow timescale.  ...  Dissipation of orbital energy creates a hot wake behind the planet, producing a EUV/soft X-ray transient as the planet sinks below the stellar surface.  ...  The predicted optical spectrum is that of a dense outflow with abundances characteristic of the stellar surface (metallicity Z ∼ Z ⊙ ).  ... 
doi:10.1111/j.1365-2966.2012.21444.x fatcat:mvzw5wwvrzcjhoi5r5cvwnreua


David S. Spiegel, Nikku Madhusudhan
2012 Astrophysical Journal  
as well as causing a significant accretion luminosity during the epochs of most intense stellar mass loss.  ...  Furthermore, massive planets around post-main-sequence stars could accrete a non-negligible amount of material from the enhanced stellar winds, thereby significantly altering their atmospheric chemistry  ...  NM acknowledges support from the Yale Center for Astronomy and Astrophysics through the YCAA postdoctoral Fellowship.  ... 
doi:10.1088/0004-637x/756/2/132 fatcat:ttss4d63mrdhjksqdvs25jap5a

Search for giant planets around seven white dwarfs in the Hyades cluster with the Hubble Space Telescope

Wolfgang Brandner, Hans Zinnecker, Taisiya Kopytova
2020 Monthly notices of the Royal Astronomical Society  
Only a small number of exoplanets has been identified in stellar cluster environments.  ...  We initiated a high angular resolution direct imaging search using the Hubble Space Telescope (HST) and its NICMOS instrument for self-luminous giant planets in orbit around seven white dwarfs in the 625  ...  Xu for helpful comments on a draft of the paper.  ... 
doi:10.1093/mnras/staa3422 fatcat:n4hjrzspd5ecdkf7g6524vvwcm

Generation of Oscillatory Motions in the Stellar Atmosphere

Yoji Osaki
1980 International Astronomical Union Colloquium  
AbstractThermal overstability of non-radial eigenmodes of stars is discussed as one of possible causes for generating non-thermal motions in the stellar atmosphere.  ...  Then, the excitation of eigen-oscillations is discussed and results of numerical studies so far made are reviewed for the vibrational stability of various stellar models against non-radial oscillations  ...  In this case, the linearized system of equations in hydrodynamics for adiabatic perturbation allows a simple solution of plane waves for velocity v , the pressure variation p' , and the density variation  ... 
doi:10.1017/s0252921100075163 fatcat:faaqtzn3ybeojconsie7yp2mm4

OUP accepted manuscript

2019 Monthly notices of the Royal Astronomical Society  
Volume complete sky surveys provide evidence for a binary origin for the formation of isolated white dwarfs with magnetic fields in excess of a MegaGauss.  ...  Interestingly, not a single high-field magnetic white dwarf has been found in a detached system suggesting that if the progenitors are indeed binaries, the companion must be removed or merge during formation  ...  Such discs are initially cold and dense compared to the hot stellar ambient meaning entrainment of hot gas could dissolve the discs.  ... 
doi:10.1093/mnras/stz2641 fatcat:sinqfd37j5a23n2kl6xrtwg7je

Astrometric Detection of Intermediate-Mass Black Holes At the Galactic Centre [article]

Eden Girma, Abraham Loeb
2018 arXiv   pre-print
An allowed population of ten 10^4 M_ IMBHs within one parsec induces an angular shift of about 65 μas yr^-1 on the position of Sgr A*, corresponding to a perpendicular velocity component magnitude of 1.6  ...  The presence of these objects induces dynamical effects on Sgr A* and the star S2, which could be detected by next generation astrometric instruments that enable micro-arcsecond astrometry.  ...  ACKNOWLEDGEMENTS This work was supported in part by the Mellon Mays Foundation and by the Black Hole Initiative at Harvard Univer-sity, which is funded by a grant from the John Templeton Foundation.  ... 
arXiv:1807.02469v1 fatcat:meq3cjf5bbdjjcm63qobbln3xu

Discovery of a young low-mass brown dwarf transiting a fast-rotating F-type star by the Galactic Plane eXoplanet (GPX) survey [article]

P. Benni, A. Y. Burdanov, V. V. Krushinsky, A. Bonfanti, G. Hébrard, J. M. Almenara, S. Dalal, O. D. S. Demangeon, M. Tsantaki, J. Pepper, K. G. Stassun, A. Vanderburg (+55 others)
2021 arXiv   pre-print
measurements, which allowed us to establish the presence of a sub-stellar object around the host star.  ...  We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of 19.7± 1.6 M_Jup and a radius of 1.47±0.10 R_Jup, the first sub-stellar object discovered by the Galactic Plane eXoplanet (GPX  ...  A.Y.B. would like to thank Catarina Fernandes and Julien de Wit for helpful discussions about the system. Organization of the EXPANSION project (E.  ... 
arXiv:2009.11899v2 fatcat:jracor3amfcahfno4quzh5dvui

Morphology and enhanced star formation in a Cartwheel-like ring galaxy

F. Renaud, E. Athanassoula, P. Amram, A. Bosma, F. Bournaud, P.-A. Duc, B. Epinat, J. Fensch, K. Kraljic, V. Perret, C. Struck
2017 Monthly notices of the Royal Astronomical Society  
We use hydrodynamical simulations of a Cartwheel-like ring galaxy, modelled as a nearly head-on collision of a small companion with a larger disc galaxy, to probe the evolution of the gaseous structures  ...  The ring ploughs the disc material as it radially extends, and almost simultaneously depletes its stellar and gaseous reservoir into the central region, through the spokes, and finally dissolve 200 Myr  ...  Rey-Raposo and Françoise Combes for discussions that helped improve the quality of this work, and the reviewer for their insightful comments.  ... 
doi:10.1093/mnras/stx2360 fatcat:fuw6xacdajcfhkc4th57ser6v4


Min Fang, Jinyoung Serena Kim, Ilaria Pascucci, Dániel Apai, Carlo Felice Manara
2016 Astrophysical Journal Letters  
Proplyd 133-353 shows a similar ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC with a similar stellar luminosity, and has a similar proper motion to the mean one of confirmed  ...  In this work, we report the discovery of a candidate planetary-mass object with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the massive star θ^1 Ori C at the center of the Orion  ...  NNX15AD94G for the program "Earths in Other Solar Systems."  ... 
doi:10.3847/2041-8213/833/2/l16 fatcat:wwyr6avbkzfyfjjenbfxmmzya4

Orbital evolution of potentially habitable planets of tidally interacting binary stars [article]

David E. Graham, David P. Fleming, Rory Barnes
2020 arXiv   pre-print
For e_bin0.5, that limit increases to 0.17M_⊙, and the HZ is partially destabilized for stellar masses up to 0.45M_⊙.  ...  This orbital evolution drives a similar evolution of the minimum CBP semi-major axis for orbital stability.  ...  The Kepler-47 system is a crucial benchmark for assessing the role of coupled stellar-tidal evolution.  ... 
arXiv:2011.10430v1 fatcat:qq3daih37nfr7h4qljt2zipkgm

Three-dimensional hydrodynamic simulations ofL2Puppis

Zhuo Chen, Jason Nordhaus, Adam Frank, Eric G. Blackman, Bruce Balick
2016 Monthly notices of the Royal Astronomical Society  
As one of nearest and brightest AGB stars, thought be a binary, L2 Puppis serves as a benchmark object for studying the late-stages of stellar evolution.  ...  Given the reported binary parameters, we are able to reproduce the current observational data if a short pulse of dense material is released from the AGB star with a velocity sufficient to escape the primary  ...  This work used the computational and visualization resources in the Center for Integrated Research Computing (CIRC) at the University of Rochester.  ... 
doi:10.1093/mnras/stw1305 fatcat:73b6c52ekbcgnb23uozdgnvjvy

An Independent Discovery of Two Hot Jupiters from theK2Mission

Rafael Brahm, Matías Jones, Néstor Espinoza, Andrés Jordán, Markus Rabus, Felipe Rojas, James S. Jenkins, Cristián Cortés, Holger Drass, Blake Pantoja, Maritza G. Soto, Maja Vučković
2016 Publications of the Astronomical Society of the Pacific  
They have physical and orbital properties similar to the ones of the already uncovered population of hot Jupiters and are well-suited candidates for further orbital and atmospheric characterization via  ...  Given that the discovery of both systems was recently reported by other groups we take the opportunity of refining the planetary parameters by including the RVs obtained by these independent studies in  ...  In addition to the large expected signal, this system possesses a nearby (≈ 1 ) stellar companion with a similar brightness, which can be used as a comparison source for T eq [K] Figure 6 .  ... 
doi:10.1088/1538-3873/128/970/124402 fatcat:pfjj34hrqraepien6gdgsjfwla

Ring Galaxies in the EAGLE Hydrodynamical Simulations

Ahmed Elagali, Claudia D P Lagos, O Ivy Wong, Lister Staveley-Smith, James W Trayford, Matthieu Schaller, Tiantian Yuan, Mario G Abadi
2018 Monthly notices of the Royal Astronomical Society  
We use the largest reference model Ref-L100N1504, a cubic cosmological volume of 100 comoving megaparsecs on a side, to identify and characterise these systems through cosmic time.  ...  At a fixed radius, the star formation efficiency of ring galaxies is indistinguishable from their star-forming counterparts, and thus the main reason for their integrated lower efficiency is the different  ...  This work used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (  ... 
doi:10.1093/mnras/sty2462 fatcat:ynexwccbibfztnde5ttt7pb44e


Benjamin J. Fulton, Karen A. Collins, B. Scott Gaudi, Keivan G. Stassun, Joshua Pepper, Thomas G. Beatty, Robert J. Siverd, Kaloyan Penev, Andrew W. Howard, Christoph Baranec, Giorgio Corfini, Jason D. Eastman (+20 others)
2015 Astrophysical Journal  
, making it one of the best targets for future atmospheric characterization studies.  ...  The low stellar g and large implied radius are supported by stellar density constraints from follow-up light curves, plus an evolutionary and space motion analysis.  ...  The Robo-AO system was developed by collaborating partner institutions, the California Institute of Technology and the Inter-University Centre for Astronomy and Astrophysics, and with the support of the  ... 
doi:10.1088/0004-637x/810/1/30 fatcat:kpuhfqs6irbxbe3vbh2ea2wjje

OUP accepted manuscript

2020 Monthly notices of the Royal Astronomical Society  
These signatures offer the potential to explore the efficiency of planet formation for host stars with masses up to the core-collapse boundary at ≈ 8M_, a mass regime rarely investigated in planet formation  ...  We find that planet formation around the highest mass white dwarf progenitors may be feasible, and hence encourage both dedicated planet formation investigations for these systems and spectroscopic analyses  ...  Support for this work was also provided by NASA through grant number HST-GO-15073.005-A from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.  ... 
doi:10.1093/mnras/staa241 fatcat:7wkdeunkj5ecdbempath42zeka
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