Optical observations of Io's neutral clouds and plasma torus

1992 ◽  
Vol 13 (2) ◽  
pp. 91-164 ◽  
Author(s):  
Nicolas Thomas
Keyword(s):  
Optical Observations ◽  
Neutral Clouds ◽  
Plasma Torus

Volcanically emitted sodium chloride as a source for Io's neutral clouds and plasma torus

Nature ◽  
2003 ◽  
Vol 421 (6918) ◽  
pp. 45-47 ◽  
Author(s):  
E. Lellouch ◽  
G. Paubert ◽  
J. I Moses ◽  
N. M. Schneider ◽  
D. F. Strobel
Keyword(s):  
Sodium Chloride ◽  
Neutral Clouds ◽  
Plasma Torus

How much Io material reaches Europa?

2020 ◽  
Author(s):  
Fran Bagenal ◽  
Vincent Dols ◽  
Edward Nerney ◽  
Frank Crary ◽  
Tim Cassidy
Keyword(s):  
Charge Exchange ◽  
Neutral Atoms ◽  
Plasma Interaction ◽  
High Energies ◽  
Energetic Neutral Atoms ◽  
Neutral Clouds ◽  
Atmosphere Interaction ◽  
Plasma Torus ◽  
Io Plasma Torus

<p>The plasma interaction with Io’s atmosphere results in at least a ton per second of escaping neutrals. Most of these neutrals supply extended neutral clouds along Io's orbit  and eventually become ionized and accelerated to corotation with Jupiter, populating the Io plasma torus as well as spreading out to fill Jupiter’s vast magnetosphere. About half to two-thirds of the plasma torus ions charge-exchange with the extended neutral clouds  and leave the torus as energetic neutral atoms, passing Europa’s orbit. Energetic neutrals are also produced directly in the plasma-atmosphere interaction, escaping with sufficient speed to reach Europa’s orbit before being ionized. The iogenic ions that are accelerated to high energies in the middle magnetosphere ultimately move back inward, again crossing Europa’s orbit. We present estimates of the fluxes of these various iogenic populations and how much oxygen, sulfur and sodium might be hitting Europa.</p>

scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

scholarly journals The Large Range of Dark Matter content in Dwarf Galaxies and its Implications

1996 ◽  
Vol 171 ◽  
pp. 435-435
Author(s):  
S.A. Pustilnik ◽  
V.A. Lipovetsky ◽  
J.-M. Martin ◽  
T.X. Thuan
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Large Range ◽  
Dwarf Galaxy ◽  
Rotational Velocity ◽  
Matter Content ◽  
Optical Observations ◽  
Strong Interactions ◽  
Formation Mechanisms ◽  
Mass Ratio

We present the analysis of a new set of radio and optical observations of a large sample of Byurakan Blue Compact Galaxies. HI spectra were obtained with the Nançay 300-m and Green Bank 43-m radio telescopes. CCD-images were taken with the KPNO 0.9-m and Whipple Observatory 1.2-m telescopes. Dark Matter (DM) to luminous mass ratios in these BCGs were found to vary from about less than 0.5 up to 14. Recent data taken from the literature indicate this same range. This result has important consequences on models of dwarf galaxy formation, indicating possibly different formation mechanisms. The standard CDM model of dwarfs formation requires large DM halos. However the formation of dwarfs as tidal debris resulting from strong interactions of massive spirals leads naturally to dwarfs with low content of DM. On Fig.1 we show DM to luminous mass ratio versus rotational velocity for our BCGs and some other galaxies.

scholarly journals The potentially hazardous NEA 2001 BB16

2019 ◽  
Vol 28 (1) ◽  
pp. 180-190
Author(s):  
Ireneusz Wlodarczyk
Keyword(s):  
Mean Value ◽  
Optical Observations ◽  
Uniform Sampling ◽  
The Earth ◽  
22Nd Century ◽  
Lyapunov Time ◽  
Gravitational Model ◽  
Calculated Probability ◽  
Potential Impact ◽  
The Impact

AbstractWe computed the impact solutions of the potentially dangerous Near Earth Asteroid (NEA) 2001 BB16 based on 47 optical observations from January 20.08316 UTC, 2001, through February 09.15740 UTC, 2016, and one radar observation from January 19.90347 UTC, 2016. We used two methods to sample the starting Line of Variation (LOV). First method, called thereafter LOV1, with the uniform sampling of the LOV parameter, out to LOV = 5 computing 3000 virtual asteroids (VAs) on both sides of the LOV, which gives 6001 VAs and propagated their orbits to JD2525000.5 TDT=February 12, 2201. We computed the non-gravitational parameterA2=(34.55±7.38)·10–14 au/d2 for nominal orbit of 2001 BB16 and possible impacts with the Earth until 2201. For potential impact in 2195 we find A2=20.0·10−14 au/d2. With a positive value of A2, 2001 BB16 can be prograde rotator. Moreover, we computed Lyapunov Time (LT) for 2001 BB16, which for all VAs, has a mean value of about 25 y. We showed that impact solutions, including the calculated probability of a possible collision of a 2001 BB16 asteroid with the Earth depends on how to calculate and take into account the appropriate gravitational model, including the number of perturbing massive asteroids. In some complicated cases, it may depend also on the number of clones calculated for a given sigma LOV1. The second method of computing the impact solutions, called thereafter LOV2, is based on a non-uniformly sampling of the LOV. We showed that different methods of sampling the LOV can give different impact solutions, but all computed dates of possible impacts of the asteroid 2001 BB16 with the Earth occur in accordance at the end of the 22nd century.

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