scholarly journals The frequency of stellar X-ray flares from a large-scale XMM-Newton sample

2015 ◽  
Vol 11 (S320) ◽  
pp. 134-137
Author(s):  
John P. Pye ◽  
Simon R. Rosen
Keyword(s):  
Solar System ◽  
Solar Flare ◽  
Space Weather ◽  
White Light ◽  
Large Scale ◽  
The Sun ◽  
X Ray ◽  
Cool Star ◽  
Exoplanetary Systems ◽  
Solar Type

AbstractWe present estimates of cool-star X-ray flare rates determined from the XMM-Tycho survey (Pyeet al. 2015, A&A, 581, A28), and compare them with previously published values for the Sun and for other stellar EUV and white-light samples. We demonstrate the importance of applying appropriate corrections, especially in regard to the total, effective size of the stellar sample. Our results are broadly consistent with rates reported in the literature for Kepler white-light flares from solar-type stars, and with extrapolations of solar flare rates, indicating the potential of stellar X-ray flare observations to address issues such as ‘space weather’ in exoplanetary systems and our own solar system.

scholarly journals Exploration of the local solar neighbourhood I: Fixed number of probes

2013 ◽  
Vol 12 (4) ◽  
pp. 271-281
Author(s):  
Daniel Cartin
Keyword(s):  
Solar System ◽  
Large Scale ◽  
Simulated Annealing Algorithm ◽  
Success Probability ◽  
Fixed Number ◽  
Milky Way Galaxy ◽  
Single Star ◽  
Engineering Models ◽  
Time Required ◽  
Large Scale Simulations

AbstractPrevious work in studying interstellar exploration by one or several probes has focused primarily either on engineering models for a spacecraft targeting a single star system, or large-scale simulations to ascertain the time required for a civilization to completely explore the Milky Way Galaxy. In this paper, a simulated annealing algorithm is used to numerically model the exploration of the local interstellar neighbourhood (i.e. of the order of ten parsecs of the Solar System) by a fixed number of probes launched from the Solar System; these simulations use the observed masses, positions and spectral classes of targeted stars. Each probe visits a pre-determined list of target systems, maintains a constant cruise speed, and only changes the direction from gravitational deflection at each target. From these simulations, it is examined how varying design choices – differing the maximum cruise speed, number of probes launched, number of target stars to be explored, and probability of avoiding catastrophic system failure per parsec – change the completion time of the exploration programme and the expected number of stars successfully visited. In addition, it is shown that improving this success probability per parsec has diminishing returns beyond a certain point. Future improvements to the model and possible implications are discussed.

scholarly journals Jets of Fragments from Catastrophic Break-up and their Astrophysical Implications

1991 ◽  
Vol 126 ◽  
pp. 383-386
Author(s):  
G. Martelli ◽  
P. Rothwell ◽  
P.N. Smith ◽  
I. Giblin ◽  
J. Martinsson ◽  
...  
Keyword(s):  
Solar System ◽  
Large Scale ◽  
Hypervelocity Impact ◽  
Preliminary Results ◽  
Artificial Rock ◽  
Solar System Bodies ◽  
Break Up ◽  
First Time

AbstractWe present some preliminary results of a series of catastrophic break-up experiments carried out in the open, against targets of natural and artificial rock, with and without a harder core. These experiments were aimed at investigating the outcomes of hypervelocity impact disruption phenomena, designed to understand the influence of large-scale collisions on the evolution of asteroids and other small solar system bodies. For the first time in this kind of experiments, evidence was found of collimated jets, i.e. the ejection of a statistically significant number of fragments all closely aligned about some preferential planes. Moreover, the presence of some groups of fragments lying close to each other on the ground was also detected.

scholarly journals Sources of Interplanetary Dust

1996 ◽  
Vol 150 ◽  
pp. 141-153 ◽  
Author(s):  
S.F. Dermott ◽  
K. Grogan ◽  
B.Å.S. Gustafson ◽  
S. Jayaraman ◽  
S.J. Kortenkamp ◽  
...  
Keyword(s):  
Solar System ◽  
Interstellar Dust ◽  
Large Scale ◽  
Thermal Flux ◽  
Interplanetary Dust ◽  
Scale Height ◽  
Size Frequency Distribution ◽  
Zodiacal Cloud ◽  
The Earth ◽  
Characteristic Features

AbstractAsteroids, comets and interstellar dust are possible sources of the particles that constitute the dust in the inner solar system. Each of these components gives rise to particular, characteristic features, the amplitudes of which can be used to estimate the size of the associated source. The asteroidal component feeds the dust bands and the Earth's resonant ring, while the cometary component may account for the large scale height of the zodiacal cloud observed at 1 AU Previous discussions of the observed strengths of these various features indicated that the source of about one third of the thermal flux observed, for example, in the IRAS 25μm waveband is asteroidal, while two thirds is cometary. However, a variety of assumptions go into this calculation (the size-frequency distribution of the particles is particularly significant) and we now know that the result is highly dependent on these assumptions. The zodiacal cloud is also the source of the IDPs collected on Earth. Because of strong gravitational focusing by the Earth of particles in low e and I orbits, it is probable that the majority of IDPs originate from asteroids, particularly those asteroids in the Themis and Koronis families.

scholarly journals Bioastronomy (Report of Iau Commission 51)

1991 ◽  
Vol 21 (1) ◽  
pp. 599-606
Author(s):  
Marx George
Keyword(s):  
Solar System ◽  
Chemical Evolution ◽  
Computer Technology ◽  
Large Scale ◽  
Planetary Systems ◽  
Origins Of Life ◽  
Systematic Survey ◽  
Radio Signals

In the recent years, science have become able to give more definite answers to the questions of the abundance of planetary systems, of the pathways of chemical evolution leading to the emergence of simple self-reproducing structures, to the origins of life within and beyond the Solar System. At the same time a new question has been raised: the duration of life-sustaining environment, what is a prerequisit for the emergence of technology. Thanks to the fast progress of computer technology, the search for intelligent radio signals has become affordable. The number of observatories participating in this venture increases rapidly. Preparations are in progress for a large scale systematic survey.

Bright carbonate veins on asteroid (101955) Bennu: Implications for aqueous alteration history

Science ◽  
2020 ◽  
Vol 370 (6517) ◽  
pp. eabc3557 ◽  
Author(s):  
H. H. Kaplan ◽  
D. S. Lauretta ◽  
A. A. Simon ◽  
V. E. Hamilton ◽  
D. N. DellaGiustina ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Solar System ◽  
Hydrothermal Alteration ◽  
Large Scale ◽  
Carbonaceous Chondrite ◽  
Parent Body ◽  
Early Solar System ◽  
Aqueous Alteration ◽  
Insight Into ◽  
Geologic Processes

The composition of asteroids and their connection to meteorites provide insight into geologic processes that occurred in the early Solar System. We present spectra of the Nightingale crater region on near-Earth asteroid Bennu with a distinct infrared absorption around 3.4 micrometers. Corresponding images of boulders show centimeters-thick, roughly meter-long bright veins. We interpret the veins as being composed of carbonates, similar to those found in aqueously altered carbonaceous chondrite meteorites. If the veins on Bennu are carbonates, fluid flow and hydrothermal deposition on Bennu’s parent body would have occurred on kilometer scales for thousands to millions of years. This suggests large-scale, open-system hydrothermal alteration of carbonaceous asteroids in the early Solar System.

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