KLENOT Project 2002–2008 contribution to NEO astrometric follow‐up

To study the effect of Cu concentration on morphological, structural, linear and nonlinear optical properties, copper-doped ZnO thin films are grown by sol-gel/ spin-coating technique on the glass substrates. Scanning electron microscopy (SEM) images reveal that the surface morphology is homogeneous with good adhesion to the glass substrate. The energy dispersive X-ray spectroscopy (EDS) spectra confirm that Zn, O, and Cu elements are present in ZnO films. The X-ray diffraction (XRD) pattern of Cu-doped ZnO is dominated by (002) peak, indicating an upstanding ZnO nanorods array growing along the c-axis. The optical bandgap of Cu-doped ZnO thin films, calculated from optical transmission spectra, is found to decrease with the increase in copper concentration. The refractive index dispersion curve of ZnO films is subjected to the single-oscillator model. The optical dispersion parameters E o , E d , and n ∞ , the nonlinear refractive index, and nonlinear optical susceptibility are calculated and interpreted.

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“…where A ¼ 1.7 Â 10 À10 esu for χ ð3Þ . [51] The linear optical susceptibility of the first order χ ð1Þ obtained by [52] χ ð1Þ ¼ ðn 2 À 1Þ 4π…”

Section: Nonlinear Optical Parametersmentioning

confidence: 99%

Influence of Cu‐Doping on Linear and Nonlinear Optical Properties of High‐Quality ZnO Thin Films Obtained by Spin‐Coating Technique

Mohammedi

Ibrir

Meglali

et al. 2021

Physica Status Solidi (b)

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“…Near-Earth object (NEO) research plays an increasingly important role not only in solar system science but also in protecting our planetary environment and human society from the hazards posed by asteroids and comets (Ticha et al 2009). Near-Earth asteroids (NEAs) are asteroids with a perihelion distance of less than 1.3 AU.…”

Section: Introductionmentioning

confidence: 99%

“…comet hazard (Ticha et al 2009). The near-Earth asteroids (NEAs) are asteroids with the perihelion distance less than 1.3AU.…”

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confidence: 99%

CCD astrometric observations of 2017 VR12, Camillo and Midas

Zhang

Chen

et al. 2019

Res. Astron. Astrophys.

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We have observed three near-Earth objects(NEOs), 2017VR12, Camillo, and Midas during the year 2018. The observations were made by the 1-m telescope of Yunnan Observatory over 2 nights. Their precise astrometric positions are derived from 989 CCD observations. The theoretical positions of asteroids are retrieved from the Jet Propulsion Laboratory (JPL) Horizons System and Institut de Mécanique Céleste et de Calcul deś Ephémérides (IMCCE). The positions of three asteroids are measured with respect to the stars in Gaia DR2 star catalogue. For 2017 VR12, the mean (O-C) of right ascension and declination are -0.090 ′′ and -0.623 ′′ based on the ephemeris of published JPL, but the mean (O-C) are 3.122 ′′ and -0.636 ′′ based on the ephemeris of published IMCCE. The great difference in declination could be explained by several factors. (1)The degenerated CCD images caused by the high apparent motion speed of the object leads to the reduction of positioning accuracy. (2)The poor timing system may bring the system error, especially in the high speed direction. (3)The asteroid may be perturbed by the earth when it approaches the earth too closely. The astrometric results show that the centroid centring method can reduce the dispersion of the non-Gaussian images compared with the PSF model method. For Camillo and Midas, the astrometric results are consistent based on two ephemerides. High-precision timing system, some astronomical effects and geometric distortion of CCD images should be carefully considered in the future works.

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“…Since 2002, the followup (mainly) and recovery efforts at Klet' have been improved through the KLENOT program, using a dedicated 1.06 m telescope equipped with a 33 ′ square camera. Over six and half years (2002)(2003)(2004)(2005)(2006)(2007)(2008), this program counted more than 1000 NEA followup observations, but only 16 NEA recoveries (Tichá 2009), suggesting that larger (preferably at least 2 m class) and larger field facilities are needed today for recovery.…”

Section: Introductionmentioning

confidence: 99%

280 one-opposition near-Earth asteroids recovered by the EURONEAR with the Isaac Newton Telescope

Văduvescu

Hudin²,

Močnik

et al. 2018

A&A

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Context. One-opposition near-Earth asteroids (NEAs) are growing in number, and they must be recovered to prevent loss and mismatch risk, and to improve their orbits, as they are likely to be too faint for detection in shallow surveys at future apparitions. Aims. We aimed to recover more than half of the one-opposition NEAs recommended for observations by the Minor Planet Center (MPC) using the Isaac Newton Telescope (INT) in soft-override mode and some fractions of available D-nights. During about 130 h in total between 2013 and 2016, we targeted 368 NEAs, among which 56 potentially hazardous asteroids (PHAs), observing 437 INT Wide Field Camera (WFC) fields and recovering 280 NEAs (76% of all targets). Methods. Engaging a core team of about ten students and amateurs, we used the THELI, Astrometrica, and the Find_Orb software to identify all moving objects using the blink and track-and-stack method for the faintest targets and plotting the positional uncertainty ellipse from NEODyS. Results. Most targets and recovered objects had apparent magnitudes centered around V ∼ 22.8 mag, with some becoming as faint as V ∼ 24 mag. One hundred and three objects (representing 28% of all targets) were recovered by EURONEAR alone by Aug. 2017. Orbital arcs were prolonged typically from a few weeks to a few years; our oldest recoveries reach 16 years. The O−C residuals for our 1854 NEA astrometric positions show that most measurements cluster closely around the origin. In addition to the recovered NEAs, 22 000 positions of about 3500 known minor planets and another 10 000 observations of about 1500 unknown objects (mostly main-belt objects) were promptly reported to the MPC by our team. Four new NEAs were discovered serendipitously in the analyzed fields and were promptly secured with the INT and other telescopes, while two more NEAs were lost due to extremely fast motion and lack of rapid follow-up time. They increase the counting to nine NEAs discovered by the EURONEAR in 2014 and 2015. Conclusions. Targeted projects to recover one-opposition NEAs are efficient in override access, especially using at least two-meter class and preferably larger field telescopes located in good sites, which appear even more efficient than the existing surveys.

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KLENOT Project 2002–2008 contribution to NEO astrometric follow‐up

Cited by 6 publications

References 4 publications

Influence of Cu‐Doping on Linear and Nonlinear Optical Properties of High‐Quality ZnO Thin Films Obtained by Spin‐Coating Technique

Influence of Cu‐Doping on Linear and Nonlinear Optical Properties of High‐Quality ZnO Thin Films Obtained by Spin‐Coating Technique

CCD astrometric observations of 2017 VR12, Camillo and Midas

280 one-opposition near-Earth asteroids recovered by the EURONEAR with the Isaac Newton Telescope

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