搜索结果: 1-15 共查到“天文学 C:N ratio”相关记录28条 . 查询时间(0.041 秒)
N-Body Simulations of Planetesimal Evolution:Effect of Varying Impactor Mass Ratio
planetesimals asteroids planetary formation collisional physics
2015/12/25
We present results from direct N-body simulations of collisions between gravitational aggregates of varying size as part of a study to parameterize planetesimal growth in the Solar System. We find tha...
Luminous Infrared Galaxies with the Submillimeter Array. I. Survey Overview and the Central Gas to Dust Ratio
infrared individual
2014/12/23
We present new data obtained with the Submillimeter Array for a sample of 14 nearby luminous and ultraluminous infrared galaxies. The galaxies were selected to have distances DL < 200 Mpc and far-infr...
Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C*
gas dust
2014/12/22
We present Herschel/HIFI observations of the fundamental rotational transitions of ortho- and para-H216O and H218O in absorption towards Sagittarius B2(M) and W31C. The ortho/para ratio in water in th...
Simulating the D/H ratio of water formed in the early solar nebula
collapsing core solar nebula dust chemistry D/H ratio of water
2017/4/11
Our solar system originated from a protoplanetary disk about 4.6 billion years ago. We simulate the formation of this
disk by a three-stage model of the solar nebula (SN) which describes the hydrodyn...
On the Ratio of Circumference to Diameter for the Largest Observable Circles: An Empirical Approach
On the Ratio of Circumference Diameter the Largest Observable Circles Empirical Approach Instrumentation and Methods for Astrophysics
2012/4/19
I present here a measurement of pi as determined for the largest observable circles. Intriguingly, the value of 16/5 asserted by the House of Representatives of the State of Indiana in 1897 is still v...
A Toy Model for 3:2:1 Ratio of HFQPOs in XTE J1550-564
black hole accretion disc magnetic field X-ray Binaries:XTE J1550-564 quasi-periodic oscillations state transition
2011/9/26
Based on a toy model of coexistence of the Blandford-Znajek (BZ) and magnetic coupling (MC) processes with a non-axisymmetric magnetic field, we explain a puzzling 3:2:1 ratio of the high-frequency Qu...
On the prior dependence of constraints on the tensor-to-scalar ratio
infl ation, primordial gravitational waves (theory), cosmological parameters from CMBR
2011/10/9
We investigate the prior dependence of constraints on cosmic tensor perturbations. Commonly imposed is the strong prior of the single-field inflationary consistency equation, relating the tensor spect...
The Galactic dust-to-metals ratio and metallicity using gamma-ray bursts
Gamma-ray burst: general – ISM: abundances – dust, extinction – Galaxy: abundances – X-rays: ISM
2011/10/18
The metallicity and dust-to-metals ratio of the Galaxy are fundamental parameters in understanding the ISM, but there is still uncertainty surrounding these parameters. In this paper, the dust-to-meta...
On the Lx-L6micron ratio as a diagnostic for Compton-thick AGN
X-rays: general X-rays: di use background X-rays: galaxies Infrared: galaxies
2011/10/11
As the mid-IR luminosity represents a good isotropic proxy of the AGN power, a low X-ray to mid-IR luminosity ratio is often claimed to be a reliable indicator for selecting Compton-thick (CT) AGN. We...
Measurement of Cosmic Ray antiproton/proton flux ratio at TeV energies with ARGO-YBJ
Extensive Air Showers Cosmic Rays Moon shadow antiproton ARGO-YBJ
2011/10/10
Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. The ARGO-YBJ experiment, l...
Stellar mass-to-light ratio gradients in galaxies: correlations with mass
dark matter – galaxies : evolution – galaxies : galaxies : general –galaxies : elliptical and lenticular, cD.
2011/10/9
We analyze the stellar mass-to-light ratio (M/L) gradients in a large sample of local galaxies taken from the Sloan Digital Sky Survey, spanning a wide range of stellar masses and morphological types....
Marginally low mass ratio close binary system V1191 Cyg
Marginally ratio close binary V1191 Cyg
2011/9/27
In this study, we present photometric and spectroscopic variations of the extremely small mass ratio ($q\simeq 0.1$) late-type contact binary system \astrobj{V1191 Cyg}. The parameters for the hot and...
The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth
realistic models mass segregation the event rate
2011/1/11
One of the most interesting sources of gravitational waves (GWs) for LISA is the inspiral of compact objects on to a massive black hole (MBH), commonly referred to as an "extreme-mass ratio inspiral" ...
Space-time variation of the electron-to-proton mass ratio in a Weyl model
Space-time variation the electron-to-proton mass ratio
2011/1/13
We consider a phenomenological model where the effective fermion masses depend on the local value of Weyl tensor as a possible explanation for the recent data indicating a space-time variation of the...
A High Signal-to-Noise Ratio Composite Spectrum of Gamma-ray Burst Afterglows
Galaxies high-redshift gamma rays bursts
2010/11/10
We present a composite spectrum of 60 long duration gamma-ray burst (GRB) afterglows with
redshifts in the range 0.35 < z < 6.7 observed with low resolution optical spectra. The composite spectrum co...