scholarly journals The reliability of the Titius–Bode relation and its implications for the search for exoplanets

2020 ◽  
Vol 72 (2) ◽  
Author(s):  
Patricia Lara ◽  
Guadalupe Cordero-Tercero ◽  
Christine Allen
Keyword(s):  
Solar System ◽  
Random Distribution ◽  
Statistical Test ◽  
Geometric Progression ◽  
Physical Origin ◽  
Exoplanetary Systems ◽  
Major Semiaxes ◽  
Using Data

Abstract The major semiaxes of the planets in our solar system obey a simple geometric progression known as the Titius–Bode (TB) relation, whose physical origin remains disputed. It has been shown that the exoplanetary systems follow a similar (but not identical) progression of the form $a_n= a_0$ e$^{bn}$, where $a_0$ and b are constants to be determined for each system. Since its formulation, the TB relation has proved to be highly predictive in our solar system. Using data from 27 exoplanetary systems with five or more planets and applying a proposed method, we conclude that reliable TB-like fits can be obtained for systems with at least four planets and that the precision of the TB relation is $78\%$. By means of a statistical test we show that the periods of planets in real exoplanetary systems are not consistent with a random distribution. Rather, they show signs that their configuration is shaped by their mutual interactions.

scholarly journals Planetary populations according to the orbital angular momentum

2009 ◽  
Vol 5 (S265) ◽  
pp. 420-421
Author(s):  
João A. S. Amarante ◽  
Helio J. Rocha-Pinto
Keyword(s):  
Angular Momentum ◽  
Solar System ◽  
Orbital Angular Momentum ◽  
Momentum Distribution ◽  
Semimajor Axis ◽  
Terrestrial Planets ◽  
Planetary Mass ◽  
Exoplanetary Systems ◽  
Planetary Migration ◽  
Two Populations

AbstractWe investigate the angular momentum distribution of known exoplanetary systems, as a function of the planetary mass, orbital semimajor axis and metallicity of the host star. We find exoplanets seems to be classified according to at least two ‘populations’, with respect to their angular momentum properties. This classification is independent on the composition of the planet and seems to be valid for both jovian and neptunian planets, and probably can be extrapolated to the terrestrial planets of the Solar System. We analyse these ‘populations’ considering the phenomenon of planetary migration.

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 Possible Transfer of Life by Earth-Grazing Objects to Exoplanetary Systems

Life ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 44
Author(s):  
Amir Siraj ◽  
Abraham Loeb
Keyword(s):  
Solar System ◽  
Binary Star ◽  
Earth’S Atmosphere ◽  
Exoplanetary Systems ◽  
Earth's Atmosphere

Recently, a 30-cm object was discovered to graze the Earth’s atmosphere and shift into a Jupiter-crossing orbit. We use the related survey parameters to calibrate the total number of such objects. The number of objects that could have exported terrestrial microbes out of the Solar System is in the range 2 × 10 9 – 3 × 10 11 . We find that 10 7 – 10 9 such objects could have been captured by binary star systems over the lifetime of the Solar System. Adopting the fiducial assumption that one polyextremophile colony is picked up by each object, the total number of objects carrying living colonies on them upon capture could be 10– 10 3 .

The Solar System Treks Mosaic Pipeline (SSTMP)

2020 ◽  
Author(s):  
Aaron Curtis ◽  
Emily Law ◽  
Shan Malhotra ◽  
Brian Day ◽  
Marshall Trautman ◽  
...  
Keyword(s):  
Solar System ◽  
Open Source ◽  
Laser Altimeter ◽  
Narrow Angle ◽  
Spatial Alignment ◽  
Stereo Reconstruction ◽  
Common Framework ◽  
Mosaic Generation ◽  
Using Data ◽  
Processing Steps

<p>Solar System Treks Mosaic Pipeline (SSTMP) is a new, open-source tool for generation of planetary DEM and orthoimage mosaics. Opportunistic stereo reconstruction from pre-existing orbital imagery has in the past typically required significant human input, particularly in the pair selection and spatial alignment steps. Previous stereo mosaics incorporate myriad human decisions, compromising the reproducibility of the process and complicating uncertainty analysis. Lack of a common framework for recording operator input has hindered the community's ability to collaborate and share experience to improve stereo reconstruction techniques. SSTMP provides a repeatable, turnkey, end-to-end solution for creating these products. The user requests mosaic generation for a bounding box or polygon, initiating a workflow which results in deliverable mosaics usable for site characterization, science, and public outreach.</p> <p>The inital release of SSTMP focuses on production of elevation and orthoimage mosaics using data from the Lunar Reconaissance Orbiter's Narrow Angle Camera (LRO NAC). SSTMP can automatically select viable stereo pairs, complete stereo reconstruction, refine alignments using data from the LRO's laser altimeter (LOLA), and combine the data to produce orthoimage, elevation, and color hillshade mosaics.</p> <p>SSTMP encapsulates the entire stereo mosaic production process into one workflow, managed by Argo Workflow opensource Kubernetes-based software. Each process runs in a container including all tools necessary for production and geospatial analysis of mosaics, ensuring a consistent computing environment. SSTMP automatically retrieves all necessary data. For processing steps, it leverages free and open-source software including Ames Stereo Pipeline, USGS ISIS, Geopandas, GDAL, and Orfeo toolbox.</p>

scholarly journals Planetary Trojans – the main source of short period comets?

2010 ◽  
Vol 9 (4) ◽  
pp. 227-234 ◽  
Author(s):  
J. Horner ◽  
P. S. Lykawka
Keyword(s):  
Solar System ◽  
Short Review ◽  
Oort Cloud ◽  
Asteroid Belt ◽  
Exoplanetary Systems ◽  
Short Period ◽  
Proximate Source ◽  
Different Origins ◽  
Near Earth Asteroids ◽  
The Impact

AbstractOne of the key considerations when assessing the potential habitability of telluric worlds will be that of the impact regime experienced by the planet. In this work, we present a short review of our understanding of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion (closest approach to the Sun) between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primarily Jupiter and Neptune). Focussing on simulations of the Neptunian Trojan population, we show that an ongoing flux of objects should be leaving that region to move on orbits within the Centaur population. With conservative estimates of the flux from the Neptunian Trojan clouds, we show that their contribution to that population could be of order ~3%, while more realistic estimates suggest that the Neptune Trojans could even be the main source of fresh Centaurs. We suggest that further observational work is needed to constrain the contribution made by the Neptune Trojans to the ongoing flux of material to the inner Solar system, and believe that future studies of the habitability of exoplanetary systems should take care not to neglect the contribution of resonant objects (such as planetary Trojans) to the impact flux that could be experienced by potentially habitable worlds.

scholarly journals The effects of stellar winds and magnetic fields on exoplanets

2013 ◽  
Vol 9 (S302) ◽  
pp. 228-236 ◽  
Author(s):  
A. A. Vidotto
Keyword(s):  
Solar System ◽  
Interplanetary Medium ◽  
Great Majority ◽  
Stellar Winds ◽  
Stellar Rotation ◽  
Low Mass Stars ◽  
Exoplanetary Systems ◽  
Cool Stars ◽  
Low Mass ◽  
Host Stars

AbstractThe great majority of exoplanets discovered so far are orbiting cool, low-mass stars whose properties are relatively similar to the Sun. However, the stellar magnetism of these stars can be significantly different from the solar one, both in topology and intensity. In addition, due to the present-day technology used in exoplanetary searches, most of the currently known exoplanets are found orbiting at extremely close distances to their host stars (< 0.1 au). The dramatic differences in stellar magnetism and orbital radius can make the interplanetary medium of exoplanetary systems remarkably distinct from that of the Solar System. To constrain interactions between exoplanets and their host-star's magnetised winds and to characterise the interplanetary medium that surrounds exoplanets, more realistic stellar wind models, which account for factors such as stellar rotation and the complex stellar magnetic field configurations of cool stars, must be employed. Here, I briefly review the latest progress made in data-driven modelling of magnetised stellar winds. I also show that the interaction of the stellar winds with exoplanets can lead to several observable signatures, some of which that are absent in our own Solar System.

scholarly journals Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal

Science ◽  
2020 ◽  
Vol 371 (6525) ◽  
pp. 168-172
Author(s):  
B. C. Kaiser ◽  
J. C. Clemens ◽  
S. Blouin ◽  
P. Dufour ◽  
R. J. Hegedus ◽  
...  
Keyword(s):  
Solar System ◽  
White Dwarf ◽  
Big Bang ◽  
Early Solar System ◽  
Big Bang Nucleosynthesis ◽  
Lithium Abundance ◽  
Sodium Potassium ◽  
Elemental Abundances ◽  
Exoplanetary Systems ◽  
Gaia Dr2

Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the systems formed, which is analogous to how meteorite abundances inform our understanding of the early Solar System. We report the detection of lithium, sodium, potassium, and calcium in the atmosphere of the white dwarf Gaia DR2 4353607450860305024, which we ascribe to the accretion of a planetesimal. Using model atmospheres, we determine abundance ratios of these elements, and, with the exception of lithium, they are consistent with meteoritic values in the Solar System. We compare the measured lithium abundance with measurements in old stars and with expectations from Big Bang nucleosynthesis.

scholarly journals Comet C/2018 V1 (Machholz–Fujikawa–Iwamoto): dislodged from the Oort Cloud or coming from interstellar space?

2019 ◽  
Vol 489 (1) ◽  
pp. 951-961 ◽  
Author(s):  
C de la Fuente Marcos ◽  
R de la Fuente Marcos
Keyword(s):  
Solar System ◽  
Dynamical Evolution ◽  
Oort Cloud ◽  
Interstellar Space ◽  
The Sun ◽  
The Past ◽  
Using Data ◽  
To Receive ◽  
Practical Feasibility

ABSTRACT The chance discovery of the first interstellar minor body, 1I/2017 U1 (‘Oumuamua), indicates that we may have been visited by such objects in the past and that these events may repeat in the future. Unfortunately, minor bodies following nearly parabolic or hyperbolic paths tend to receive little attention: over 3/4 of those known have data-arcs shorter than 30 d and, consistently, rather uncertain orbit determinations. This fact suggests that we may have observed interstellar interlopers in the past, but failed to recognize them as such due to insufficient data. Early identification of promising candidates by using N-body simulations may help in improving this situation, triggering follow-up observations before they leave the Solar system. Here, we use this technique to investigate the pre- and post-perihelion dynamical evolution of the slightly hyperbolic comet C/2018 V1 (Machholz–Fujikawa–Iwamoto) to understand its origin and relevance within the context of known parabolic and hyperbolic minor bodies. Based on the available data, our calculations suggest that although C/2018 V1 may be a former member of the Oort Cloud, an origin beyond the Solar system cannot be excluded. If extrasolar, it might have entered the Solar system from interstellar space at low relative velocity with respect to the Sun. The practical feasibility of this alternative scenario has been assessed within the kinematic context of the stellar neighbourhood of the Sun, using data from Gaia second data release, and two robust solar sibling candidates have been identified. Our results suggest that comets coming from interstellar space at low heliocentric velocities may not be rare.

scholarly journals Practice of Sustainability in Higher Education

2018 ◽  
Vol 7 (3.25) ◽  
pp. 84 ◽  
Author(s):  
Alia Ariesanti ◽  
Eko Ganis Sukoharsono ◽  
Gugus Irianto ◽  
Erwin Erwin Saraswati
Keyword(s):  
Higher Education ◽  
Community Service ◽  
Mixed Method ◽  
Qualitative Data ◽  
Curriculum Implementation ◽  
Statistical Test ◽  
Data Display ◽  
Service Activities ◽  
Using Data ◽  
Method Approach

Higher education have a significant role in supporting the realization of sustainable development, thus forming the concept of the sustainable university. The concept of the sustainable university emphasizes the importance of economic, environmental and social activities conducted by the college. The college is expected to formulate the curriculum, perform research and community service activities with the topic of sustainability. The purpose of this study was to assess the extent of higher education considering the environmental, social and economical in their activities. The respondents of this study are the head of a department in Ahmad Dahlan University, Indonesia. This study uses a mixed method approach. Quantitative data obtained using a questionnaire, then processed by using the compared group statistical test. Qualitative data obtained using interview, then processed by using data reduction, data display and conclusion and verification. The results of this survey suggest that the head of the departments had considered the aspect of sustainability in formulating the curriculum, implementation of research and community service activities. From the three points of the Tridharma, which is learning and curricula, research and community service, the departments give more attention to community service activities.  

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