New upper limits of a braneworld model with recent Solar System tests

2016 ◽  
Vol 31 (05) ◽  
pp. 1650021 ◽  
Author(s):  
Xue-Mei Deng ◽  
Yi Xie
Keyword(s):  
Time Delay ◽  
Solar System ◽  
Upper Bounds ◽  
Physical Experiments ◽  
Dimensional Spacetime ◽  
Upper Limits ◽  
Perihelion Shift ◽  
Braneworld Model ◽  
Charge Parameter ◽  
First Time

As an extension of previous works on classical tests of a braneworld model which is called as the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) solution, and as an attempt to find more stringent constraints on this model, we investigate its effects on physical experiments and astronomical observations conducted in the Solar System by modeling new observable effects and adopting new datasets. First, we investigate gravitational time delay at inferior conjunction (IC) caused by the braneworld model, which was not considered in previous works, because these measurements are not affected by the solar corona noise. Second, the Cassini superior conjunction (SC) experiment is, for the first time, used to test the DMPR model. Third, compared to previous works, we refine the model, which confronts the perihelion shift induced by the braneworld model with modern Solar System ephemerides INPOP10a (IMCCE, France) and EPM2011 (IAA RAS, Russia). The correction of DMPR solution to Einstein’s general relativity (GR) in the four-dimensional spacetime can be characterized by a constant bulk “tidal charge” parameter [Formula: see text], which is confined in the present work. We find that time delay experiment at IC is independent of [Formula: see text] and not suitable for testing the braneworld model. However, the Cassini SC experiment and modern Solar System ephemerides can give better upper bounds on [Formula: see text]: (1) [Formula: see text] by Cassini, and (2) [Formula: see text] based on the supplementary advances of the perihelia provided by INPOP10a and [Formula: see text] based on the ones of EPM2011. The latter upper bounds are improved to be tighter than the ones of previous works by at least two orders of magnitude. Besides, the stronger constraints on the brane tension are given by the modern ephemerides, which are [Formula: see text] for INPOP10a and [Formula: see text] for EPM2011. These improved upper bounds mean that the Solar System tests can serve as a good testbed for high dimensional theories.

scholarly journals Survey of planetesimal belts with ALMA: gas detected around the Sun-like star HD 129590

2020 ◽  
Vol 497 (3) ◽  
pp. 2811-2830 ◽  
Author(s):  
Quentin Kral ◽  
Luca Matrà ◽  
Grant M Kennedy ◽  
Sebastian Marino ◽  
Mark C Wyatt
Keyword(s):  
Solar System ◽  
Main Sequence ◽  
Signal To Noise Ratio ◽  
Gas Detection ◽  
Continuum Emission ◽  
Geometrical Properties ◽  
Upper Limits ◽  
Co Detection ◽  
Outgassing Rate ◽  
First Time

ABSTRACT Gas detection around main-sequence stars is becoming more common with around 20 systems showing the presence of CO. However, more detections are needed, especially around later spectral type stars to better understand the origin of this gas and refine our models. To do so, we carried out a survey of 10 stars with predicted high likelihoods of secondary CO detection using ALMA in band 6. We looked for continuum emission of mm-dust as well as gas emission (CO and CN transitions). The continuum emission was detected in 9/10 systems for which we derived the discs’ dust masses and geometrical properties, providing the first mm-wave detection of the disc around HD 106906, the first mm-wave radius for HD 114082, 117214, HD 15745, HD 191089, and the first radius at all for HD 121191. A crucial finding of our paper is that we detect CO for the first time around the young 10–16 Myr old G1V star HD 129590, similar to our early Sun. The gas seems colocated with its planetesimal belt and its total mass is likely in the range of (2–10) × 10−5 M⊕. This first gas detection around a G-type main-sequence star raises questions as to whether gas may have been released in the Solar system as well in its youth, which could potentially have affected planet formation. We also detected CO gas around HD 121191 at a higher signal-to-noise ratio than previously and find that the CO lies much closer-in than the planetesimals in the system, which could be evidence for the previously suspected CO viscous spreading owing to shielding preventing its photodissociation. Finally, we make estimates for the CO content in planetesimals and the HCN/CO outgassing rate (from CN upper limits), which we find are below the level seen in Solar system comets in some systems.

scholarly journals Determining habitability: which exoEarths should we search for life?

2010 ◽  
Vol 9 (4) ◽  
pp. 273-291 ◽  
Author(s):  
J. Horner ◽  
B.W. Jones
Keyword(s):  
Solar System ◽  
Positive Result ◽  
Habitable Zone ◽  
Detailed Search ◽  
First Time

AbstractWithin the next few years, the first Earth-mass planets will be discovered around other stars. Some of those worlds will certainly lie within the classical ‘habitable zone’ of their parent stars, and we will quickly move from knowing of no exoEarths to knowing many. For the first time, we will be in a position to carry out a detailed search for the first evidence of life beyond our Solar System. However, such observations will be hugely taxing and time consuming to perform, and it is almost certain that far more potentially habitable worlds will be known than it is possible to study. It is therefore important to catalogue and consider the various effects that make a promising planet more or less suitable for the development of life. In this work, we review the various planetary, dynamical and stellar influences that could influence the habitability of exoEarths. The various influences must be taken in concert when we attempt to decide where to focus our first detailed search for life. While there is no guarantee that any given planet will be inhabited, it is vitally important to ensure that we focus our time and effort on those planets most likely to yield a positive result.

scholarly journals Efficient Nonrecursive Bit-Parallel Karatsuba Multiplier for a Special Class of Trinomials

VLSI Design ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yin Li ◽  
Yu Zhang ◽  
Xiaoli Guo
Keyword(s):  
Time Delay ◽  
Special Class ◽  
Time Complexity ◽  
Space Complexity ◽  
Polynomial Basis ◽  
Gate Delay ◽  
Complexity Bound ◽  
Parallel Multiplier ◽  
Highly Efficient ◽  
First Time

Recently, we present a novel Mastrovito form of nonrecursive Karatsuba multiplier for all trinomials. Specifically, we found that related Mastrovito matrix is very simple for equally spaced trinomial (EST) combined with classic Karatsuba algorithm (KA), which leads to a highly efficient Karatsuba multiplier. In this paper, we consider a new special class of irreducible trinomial, namely, xm+xm/3+1. Based on a three-term KA and shifted polynomial basis (SPB), a novel bit-parallel multiplier is derived with better space and time complexity. As a main contribution, the proposed multiplier costs about 2/3 circuit gates of the fastest multipliers, while its time delay matches our former result. To the best of our knowledge, this is the first time that the space complexity bound is reached without increasing the gate delay.

scholarly journals CAPTURE OF DARK MATTER BY THE SOLAR SYSTEM

2009 ◽  
Vol 18 (12) ◽  
pp. 1903-1912 ◽  
Author(s):  
I. B. KHRIPLOVICH ◽  
D. L. SHEPELYANSKY
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
Dark Matter Particle ◽  
Matter Density ◽  
Upper And Lower Bounds ◽  
Analytical Estimate ◽  
Upper Limits ◽  
Galactic Dark Matter ◽  
Three Body ◽  
Optimistic Value

We study the capture of galactic dark matter by the solar system. The effect is due to the gravitational three-body interaction between the sun, one of the planets, and a dark matter particle. The analytical estimate for the capture cross-section is derived and the upper and lower bounds for the total mass of the captured dark matter particles are found. The estimates for their density are less reliable. The most optimistic of them gives an enhancement of dark matter density by about three orders of magnitudes compared to its value in our galaxy. However, even this optimistic value remains below the best present observational upper limits by about two orders of magnitude.

scholarly journals A census of the pulsar population observed with the international LOFAR station FR606 at low frequencies (25–80 MHz)

2020 ◽  
Vol 635 ◽  
pp. A76 ◽  
Author(s):  
L. Bondonneau ◽  
J.-M. Grießmeier ◽  
G. Theureau ◽  
A. V. Bilous ◽  
V. I. Kondratiev ◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Range ◽  
Radio Pulsars ◽  
Low Frequencies ◽  
Radio Observatory ◽  
Future Studies ◽  
New Information ◽  
Upper Limits ◽  
Widespread Phenomenon ◽  
First Time

Context. To date, only 69 pulsars have been identified with a detected pulsed radio emission below 100 MHz. A LOFAR-core LBA census and a dedicated campaign with the Nançay LOFAR station in stand-alone mode were carried out in the years 2014–2017 in order to extend the known population in this frequency range. Aims. In this paper, we aim to extend the sample of known radio pulsars at low frequencies and to produce a catalogue in the frequency range of 25–80 MHz. This will allow future studies to probe the local Galactic pulsar population, in addition to helping explain their emission mechanism, better characterising the low-frequency turnover in their spectra, and obtaining new information about the interstellar medium through the study of dispersion, scattering, and scintillation. Methods. We observed 102 pulsars that are known to emit radio pulses below 200 MHz and with declination above −30°. We used the Low Band Antennas (LBA) of the LOw Frequency ARray (LOFAR) international station FR606 at the Nançay Radio Observatory in stand-alone mode, recording data between 25 and 80 MHz. Results. Out of our sample of 102 pulsars, we detected 64. We confirmed the existence of ten pulsars detected below 100 MHz by the LOFAR LBA census for the first time (Bilous et al. 2020, A&A, 635, A75) and we added two more pulsars that had never before been detected in this frequency range. We provided average pulse profiles, DM values, and mean flux densities (or upper limits in the case of non-detections). The comparison with previously published results allows us to identify a hitherto unknown spectral turnover for five pulsars, confirming the expectation that spectral turnovers are a widespread phenomenon.

scholarly journals Upper limits on the water vapour content of the β Pictoris debris disk

2019 ◽  
Vol 628 ◽  
pp. A127 ◽  
Author(s):  
M. Cavallius ◽  
G. Cataldi ◽  
A. Brandeker ◽  
G. Olofsson ◽  
B. Larsson ◽  
...  
Keyword(s):  
Solar System ◽  
Far Infrared ◽  
Kinetic Temperature ◽  
Line Flux ◽  
Water Vapour Content ◽  
Water Ice ◽  
Upper Limit ◽  
Upper Limits ◽  
Debris Disk ◽  
Lower Limits

Context. The debris disk surrounding β Pictoris has been observed with ALMA to contain a belt of CO gas with a distinct peak at ~85 au. This CO clump is thought to be the result of a region of enhanced density of solids that collide and release CO through vaporisation. The parent bodies are thought to be comparable to solar system comets, in which CO is trapped inside a water ice matrix. Aims. Since H2O should be released along with CO, we aim to put an upper limit on the H2O gas mass in the disk of β Pictoris. Methods. We used archival data from the Heterodyne Instrument for the Far-Infrared (HIFI) aboard the Herschel Space Observatory to study the ortho-H2O 110–101 emission line. The line is undetected. Using a python implementation of the radiative transfer code RADEX, we converted upper limits on the line flux to H2O gas masses. The resulting lower limits on the CO/H2O mass ratio are compared to the composition of solar system comets. Results. Depending on the assumed gas spatial distribution, we find a 95% upper limit on the ortho-H2O line flux of 7.5 × 10−20 W m−2 or 1.2 × 10−19 W m−2. These translate into an upper limit on the H2O mass of 7.4 × 1016–1.1 × 1018 kg depending on both the electron density and gas kinetic temperature. The range of derived gas-phase CO/H2O ratios is marginally consistent with low-ratio solar system comets.

scholarly journals Panspermia - A Modern Astrophysical and Biological Approach

1985 ◽  
Vol 112 ◽  
pp. 157-164
Author(s):  
J. Mayo Greenberg ◽  
Peter Weber
Keyword(s):  
Solar System ◽  
Life Expectancy ◽  
Molecular Clouds ◽  
Random Motion ◽  
Bacterial Spore ◽  
Laboratory Simulation ◽  
Percent Survival ◽  
Biological Approach ◽  
Quantitative Estimates ◽  
First Time

For the first time a laboratory simulation of the effect of the interstellar environment has been used to provide quantitative estimates of bacterial spore survival in the space between the stars. In the diffuse regions between clouds ten percent survival is limited to at most hundreds of years although one in ten thousand may survive for several thousand years. Within common dense clouds the ten percent life expectancy is extended to tens of millions of years because of the severely reduced ultraviolet within these clouds as well as because of the accretion of ultraviolet absorbing mantles on the spores. The random motion of molecular clouds is shown to provide a possible vehicle for transport of spores from one solar system to another. The most hazardous times in such a journey are at the start and finish and, although the requirements for survival during these periods are quantified here, the possibility or probability of their being satisfied remains pure conjecture.

scholarly journals Molecules in Comets: A Tool to Estimate the Low Energy Cosmic Ray Flux Outside the Solar System?

1987 ◽  
Vol 120 ◽  
pp. 443-445
Author(s):  
Valerio Pirronello
Keyword(s):  
Solar System ◽  
Chemical Species ◽  
Cosmic Ray ◽  
Low Energy ◽  
Chemical Modifications ◽  
Cometary Nuclei ◽  
First Time ◽  
Cosmic Ray Flux

It is described a method for evaluating the low energy cosmic ray flux outside the heliosphere. It is based on the chemical modifications induced in cometary nuclei by impinging ions and on the release of synthesized chemical species by comets entering for the first time into the inner solar system.

scholarly journals Search for L5 Earth Trojans with DECam

2020 ◽  
Vol 492 (4) ◽  
pp. 6105-6119
Author(s):  
Larissa Markwardt ◽  
D W Gerdes ◽  
R Malhotra ◽  
J C Becker ◽  
S J Hamilton ◽  
...  
Keyword(s):  
Solar System ◽  
Confidence Limit ◽  
System Support ◽  
Lagrange Points ◽  
Magnitude Distribution ◽  
Upper Limits

ABSTRACT Most of the major planets in the Solar system support populations of co-orbiting bodies, known as Trojans, at their L4 and L5 Lagrange points. In contrast, Earth has only one known co-orbiting companion. This paper presents the results from a search for Earth Trojans (ETs) using the DECam instrument on the Blanco Telescope at CTIO. This search found no additional Trojans in spite of greater coverage compared to previous surveys of the L5 point. Therefore, the main result of this work is to place the most stringent constraints to date on the population of ETs. These constraints depend on assumptions regarding the underlying population properties, especially the slope of the magnitude distribution (which in turn depends on the size and albedo distributions of the objects). For standard assumptions, we calculate upper limits to a 90 per cent confidence limit on the L5 population of NET < 1 for magnitude H < 15.5, NET = 60–85 for H < 19.7, and NET = 97 for H = 20.4. This latter magnitude limit corresponds to Trojans ∼300 m in size for albedo 0.15. At H = 19.7, these upper limits are consistent with previous L4 ET constraints and significantly improve L5 constraints.

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