共查询到20条相似文献，搜索用时 15 毫秒
1.
《New Astronomy》2016
We carried out light curve solutions of four detached binaries with circular orbits, observed by Kepler. As a result their orbital inclinations, temperatures and relative stellar radii were determined. We estimated also their global parameters on the base of the obtained solutions and empirical relation “temperature, luminosity” for MS stars. The out-of-eclipse light curves of KIC 5080652, KIC 9236858 and KIC 11975363 reveal a trend the bigger amplitudes to correspond to single-waved shape while the two-waved shape to be inherent to the smaller amplitudes. This type of variability was attributed to gradually transition between state with two almost opposite cool spots and state with bigger in size polar spot. We detected also several microflares of KIC 11975363 with amplitudes of 0.002–0.003 mag. 相似文献
2.
We present the physical parameters of three short period close binaries using data observed from the Kepler Space Telescope. All of these observations were taken in a single bandpass(which approximates the Johnson V-band). Our three systems are KIC 2715417, KIC 6050116 and KIC 6287172. The first system, KIC 2715417, is considered a semi-detached system with the secondary component filling its Roche lobe. The second system, KIC 6050116, is an overcontact system, while the third system, KIC 6287172, belongs to ellipsoidal variables as deduced from the Roche lobe geometry. For photometric analysis, we used the PHOEBE software package, which is based on the Wilson-Devinney code. Due to lack of spectroscopic data, the photometric mass ratios are determined from the analyses of light curves using the q-search method. The absolute parameters are determined using three different methods(Harmanec, Maceroni Van'tVeer and Gazeas Niarchos). 相似文献
3.
《New Astronomy》2016
The paper presents our light curve solutions of the Kepler data of two eccentric, eclipsing binaries: KIC 4281895 and KIC 5115178. The derived orbital and stellar parameters reveal that their components are of G spectral type and undergo partial eclipses. We found tidally-induced light humps around the periastron phases of the two targets which are appearances of the recently discovered “heartbeat” phenomenon. 相似文献
4.
《New Astronomy》2019
KIC 10684673 (TYC 3562-805-1) was observed by the Kepler mission, which obtained nearly 50,000 data points in the short cadence mode from May through June of 2009 for a total of about 33 days. It has been added to the Kepler Eclipsing Binary Catalog as an eclipsing binary. However it is flagged as uncertain in nature. Upon visual inspection, it is found the light curve is not consistent with features present in light curves from typical eclipsing binary systems. Instead, it shows features more consistent with pulsation. In the present study, it is shown the light curve can be satisfactorily modeled by considering the target as single, multi-modal δ Scuti pulsator. 相似文献
8.
The LAMOST spectra and Kepler light curves are combined to investigate the detached eclipsing binary KIC 8098300,which shows the O'Connell effect caused by spot... 相似文献
9.
《New Astronomy》2016
In this paper we study the field of Kepler open cluster NGC 6866 using the data obtained from Kepler mission collected for a period of 4 years. We search for the red clump (RC) stars amongst the red giant (RG) stars showing solar-like oscillations using median gravity-mode period spacings (ΔP). We find a RG star KIC 8263801 having median gravity-mode period spacing 173.7 ± 6.4 s. We claim based on the median gravity-mode period spacing that KIC 8263801 is a secondary red clump (SRC) star which is massive enough to have ignited Helium burning in a non degenerate core. In the literature, no classification for KIC 8263801 has been provided. This is the first time that a star located in the field of NGC 6866 is classified in this manner. 相似文献
10.
Two years of Kepler spacecraft data of the δ Sct/γ Dor star KIC 9764965 revealed 67 statistically significant frequencies from 0.45 to 59.17 c d–1 (0.005 to 0.685 mHz). The 19 low frequencies do not show equidistant period spacing predicted for gravity modes of successive radial order. We note a favored frequency spacing of 2.053 c d–1 that appears in both the low‐frequency (gravity mode) region and high‐frequency (pressure mode) regions. The value of this frequency spacing also occurs as a dominant low frequency and in a high‐frequency triplet. A peak at exactly twice the value of the 2.053 cd–1 mode is shown not to be a Fourier harmonic of the low‐frequency peak due to a different amplitude variability. This behavior is also seen in other δ Sct stars. The test for resonant mode coupling between low and high frequencies could not be carried out due to the small amplitudes of the peaks, making it difficult to separate the parent and child modes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
11.
Paradoxical properties of the KIC 8462852 object discovered in the course the Kepler mission are considered. It has been shown that the assumptions about the nature of the object as a swarm of cometary bodies, fragments resulting from catastrophic collisions of asteroids, or the KIC 8462852b exoplanet meet serious problems and even contradict the Kepler laws, if the eclipsing object is considered as a physical body orbiting a central star. According the energy and other requirements, the hypothetical orbit of KIC 8462852b does not meet the Dyson sphere conception either. In the paper, we used the materials of the study by Boyajian et al. (2015) and the subsequent publications on this theme. 相似文献
12.
The paper considers morphology of craters, smooth surfaces, and flows as well as signatures of layering observed on nuclei of Borrelly, Wild 2, and Tempel 1. In our analysis, we emphasize the role of the so-called planation process, which involves avalanche-type flows and can be responsible for the formation of flow-like features, smooth terrains, terraces, and flat floors of some craters observed on cometary nuclei. In agreement with some other researchers (e.g., Belton, 2006), we suggest that in the thicker layers on Tempel 1 and in some features on Borrelly and Wild 2, we may see elements of the comet primordial structure. We also see more and less degraded impact craters formed early in the comet history in distant parts of the Solar System and landforms formed very recently during comet visits to the inner part of the Solar System. The recent resurfacing processes certainly changed the nucleus surface materials, possibly enhancing the sublimation of volatile species, so it should be taken into account in interpretations of the Deep Impact results and in selecting study areas when the Rosetta spacecraft will approach its target comet. 相似文献
13.
A report on preliminary results obtained from the analysis of the first 700 orbits of data obtained in the University of Rochester particle telescope, carried in the wheel section of OSO-III, is presented. The telescope is sensitive to high-energy -rays (threshold 50 MeV) and the nuclear component of the cosmic radiation. An upper limit of 3.2 × 10–4 /cm2secster. is set on the intensity of the diffuse primary -radiation, on the assumption it arises from the decay of ° mesons produced in nuclear interactions. An upper limit to the flux from the sun, on the same assumptions, is set at 5.5 × 10–5 /cm2 sec. The analysis of the charged particle data yields the integral rigidity spectra of proton and helium nuclei from 3 to 15 GV; the results indicate that the He spectrum is slightly steeper than the proton spectrum and that the ratio P/He increases slowly from a value of approximately 6 at 3 GV to 8 at 15 GV.NASA Predoctoral Trainee. 相似文献
14.
Radial spacing between concentric rings of impact basins that lack central peaks is statistically similar and nonrandom on the Moon, Mercury, and Mars, both inside and outside the main ring. One spacing interval, (2.0 ± 0.3)0.5D, or an integer multiple of it, dominates most basin rings. Three analytical approaches yield similar results from 296 remapped or newly mapped rings of 67 multi-ringed basins: least-squares of rank-grouped rings, least-squares of rank and ring diameter for each basin, and averaged ratios of adjacent rings. Analysis of 106 rings of 53 two-ring basins by the first and third methods yields an integer multiple (2 ×) of 2.00.5D. There are two exceptions: (1) Rings adjacent to the main ring of multi-ring basins are consistently spaced at a slightly, but significantly, larger interval, (2.1 ± 0.3)0.5D; (2) The 88 rings of 44 protobasins (large peak-plus-inner-ring craters) are spaced at an entirely different interval (3.3 ± 0.6)0.5D.The statistically constant and target-invariant spacing of so many rings suggests that this characteristic may constrain formational models of impact basins on the terrestrial planets. The key elements of such a constraint include: (1) ring positions may not have been located by the same process(es) that formed ring topography; (2) ring location and emplacement of ring topography need not be coeval; (3) ring location, but not necessarily the mode of ring emplacement, reflects one process that operated at the time of impact; and (4) the process yields similarly-disposed topographic features that are spatially discrete at 20.5D intervals, or some multiple, rather than continuous. These four elements suggest that some type of wave mechanism dominates the location, but not necessarily the formation, of basin rings. The waves may be standing, rather than travelling. The ring topography itself may be emplaced at impact by this and/or other mechanisms and may reflect additional, including post-impact, influences. 相似文献
15.
We use high-resolution three-dimensional numerical models of aerodynamically disrupted asteroids to predict the characteristic properties of small impact craters on Venus. We map the mass and kinetic energy of the impactor passing though a plane near the surface for each simulation, and find that the typical result is that mass and energy sort themselves into one to several strongly peaked regions, which we interpret as more-or-less discrete fragments. The fragments are sufficiently well separated as to imply the formation of irregular or multiple craters that are quite similar to those found on Venus. We estimate the diameters of the resulting craters using a scaling law derived from the experiments of Schultz and Gault (1985, J. Geophys. Res. 90 (B5), 3701-3732) of dispersed impactors into targets. We compare the spacings and sizes of our estimated craters with measured diameters tabulated in a Venus crater database (Herrick and Phillips, 1994a, Icarus 111, 387-416; Herrick et al., 1997, in: Venus II, Univ. of Arizona Press, Tucson, AZ, pp. 1015-1046; Herrick, 2003, http://www.lpi.usra.edu/research/vc/vchome.html) and find quite satisfactory agreement, despite the uncertainty in our crater diameter estimates. The comparison of the observed crater characteristics with the numerical results is an after-the-fact test of our model, namely the fluid-dynamical treatment of large impacts, which the model appears to pass successfully. 相似文献
16.
《Icarus》1987,71(2):250-256
Estimates of the total inventory of the volatile elements C, H, O, and N on Mars, based upon atmospheric gas tracers, vary by a factor of 25 among different authors. Accretion of comets as the source of volatiles can account for less than 5% of the actual inventory, assuming the chondritic S/Cl abundance ratio in comets and a Martian outgassing ratio for these two elements no lower than for the estimated excess volatile inventory on Earth. Sulfate salt formation with the igneous minerals in the regolith can be a major sink for H2O, but first will recycle C and N incorporated in carbonate and nitrate minerals back to the atmosphere. Extrusive and shallow intrusive volcanism, at a persistent but decreasing rate, can interfere with this volatile recycling by irreversibly masking much of the incorporated inventory, resulting in the inevitable evolution to a relatively volatile-poor environment at the outermost, observable surface of Mars. 相似文献
17.
This paper presents a brief report about the topics discussed at the second Indian National Workshop on Solar Physics held in September 1987. 相似文献
18.
Laser-induced plasmas in various gas mixtures were used to simulate lightning in other planetary atmospheres. This method of simulation has the advantage of producing short-duration, high-temperature plasmas free from electrode contamination. The laser-induced plasma discharges in air are shown to accurately simulate terrestrial lightning and can be expected to simulate lightning spectra in other planetary atmospheres. Spectra from 240 to 880 nm are presented for simulated lightning in the atmospheres of Venus, Earth, Jupiter, and Titan. The spectra of lightning on the other giant planets are expected to be similar to that of Jupiter because the atmospheres of these planets are composed mainly of hydrogen and helium. The spectra of Venus and Titan show substantial amounts of radiation due to the presence of carbon atoms and ions and show CN Violet radiation. Although small amounts of CH4 and NH3 are present in the Jovian atmosphere, only emission from hydrogen and helium is observed. Most differences in the spectra can be understood in terms of the elemental ratios of the gas mixtures. Consequently, observations of the spectra of lightning on other planets should provide in situ estimates of the atmospheric and aerosol composition in the cloud layers in which lightning is occuring. In particular, the detection of inert gases such as helium should be possible and the relative abundance of these gases compared to major constituents might be determined. 相似文献
19.
Hoover Richard B. Hoyle Fred Wickramasinghe N. C. Hoover Miriam J. Al-Mufti S. 《Earth, Moon, and Planets》1986,35(1):19-45
There exists a close correspondence between the measured infrared properties of diatoms and the infrared spectrum of interstellar dust as observed in the Trapezium nebula and toward the galactic center source GC-IRS 7. Diatoms and bacteria also exhibit an absorbance peak near 2200 », which is found to agree with the observed ultraviolet absorbance properties of interstellar grains. We review the observational data and consider the known properties of diatoms and bacteria. It is suggested that these characteristics are consistent with the concept of a cosmic microbiological system in which these or similar microorganisms might exist on comets, Europa and in interstellar space. 相似文献
20.
Richard B. Hoover Fred Hoyle N.C. Wickramasinghe Miriam J. Hoover S. Al-Mufti 《Astrophysics and Space Science》1999,268(1-3):197-224
There exists a close correspondence between the measured infrared properties of diatoms and the infrared spectrum of interstellar dust as observed in the Trapezium nebula and toward the galactic center source GC-IRS 7. Diatoms and bacteria also exhibit an absorbance peak near 2200 Å, which is found to agree with the observed ultraviolet absorbance properties of interstellar grains. We review the observational data and consider the known properties of diatoms and bacteria. It is suggested that these characteristics are consistent with the concept of acosmic microbiological system in which these or similar microorganisms might exist on comets, Europa and in interstellar space. 相似文献