Visible and near-infrared observations of interstellar comet 2I/Borisov with the 10.4-m GTC and the 3.6-m TNG telescopes

ABSTRACT In this work, we present the results of an observational study of 2I/Borisov carried out with the 10.4-m Gran Telescopio Canarias (GTC) and the 3.6-m Telescopio Nazionale Galileo (TNG), both telescopes located at the Roque de Los Muchachos Observatory, in the island of La Palma (Spain). The study includes images in the visible and near-infrared, as well as visible spectra in the 3600–9200 Å wavelength range. N-body simulations were also performed to explore its orbital evolution and Galactic kinematic context. The comet’s dust continuum and near-infrared colours are compatible with those observed for Solar system comets. From its visible spectrum on the nights of 2019 September 24 and 26, we measured CN gas production rates Q(CN) = (2.3 ± 0.4) × 1024 mol s−1 and Q(CN) = (9.5 ± 0.2) × 1024 mol s−1, respectively, in agreement with measurements reported by other authors on similar nights. We also obtained an upper limit for the C2 production rate of Q(C2) < (4.5 ± 0.1) × 1024 mol s−1. Dust modelling results indicate a moderate dust production rate of ∼50 kg s−1 at heliocentric distance rh = 2.6 au, with a differential power-law dust size distribution of index ∼–3.4, within the range reported for many comet comae. Our simulations show that the Galactic velocity of 2I/Borisov matches well that of known stars in the solar neighbourhood and also those of more distant regions of the Galactic disc.

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Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

10.5194/amt-2019-103 ◽

2019 ◽

Author(s):

Jeremy E. Solbrig ◽

Steven D. Miller ◽

Jianglong Zhang ◽

Lewis Grasso ◽

Anton Kliewer

Keyword(s):

Near Infrared ◽

Correlation Coefficients ◽

Visible Spectrum ◽

Light Sources ◽

Infrared Observations ◽

Spatially Resolved ◽

Relative Standard ◽

Geometric Variables ◽

The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

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Comet Kohoutek: Ground and Airborne High Resolution Tilting Filter IR Photometry

International Astronomical Union Colloquium ◽

10.1017/s025292110050102x ◽

1976 ◽

Vol 25 (Part1) ◽

pp. 357-360

Author(s):

C. Barbieri ◽

C. B. Cosmovici ◽

S. Drapatz ◽

K. W. Michel ◽

T Nishimura ◽

...

Keyword(s):

High Resolution ◽

Production Rate ◽

Near Infrared ◽

Gas Production ◽

Volatile Components ◽

The Sun ◽

Dust Production ◽

Production Rates ◽

Fabry Perot ◽

Vibration Rotation

AbstractBecause of Comet Kohoutek's anticipated large gas production, which seemed to offer a unique chance to reveal parent molecules, two Fabry-Perot Tilting Filter Photometers were designed with the purpose to detect and study the behaviour of CH4 and its photolysis product H2 The importance of these two molecules is well known and their detection would have given valuable indications about the structure of the nucleus, its thermal history and conditions of formation.Similar to CH4, H2 has no dipole moment and cannot be detected by radioastronomy. The most obvious way for measuring H2 in extended cometary comae is certainly on the basis of fluorescence from the Lyman bands around 1000Å, there are, however, vibrational quadrupole transitions within the overtone bands of the ground electronic state which give rise to emissions in the near infrared, accessible by means of ground based telescopes. Three of the stronger lines are: λ = 0.8748 μ; 0.8560 μ and 0.8497 μ. Methane is more readily detectable in the infrared, since it has strong fundamental (1-0) infrared vibration rotation bands at 3.3 μ (ν3).In order to measure both the CH4 concentration and its rotational temperature, a. very high resolution (~3.7A) high throughput instrument was designed which could isolate several individual vibration-rotation lines in the v3 band, namely the P2, P3 and P9 lines. The instrument consisting of a Fabry-Periot Tilting Filter Photometer with InSb detector interfaced with the 30 cm f/30 Dahl-Kirkham Telescope is described in detail elsewhere.( l). The observations were made in January from the NASA Convair 990 (Galileo II) at an altitude of 13 km, where atmospheric methane absorption can be minimized but not avoided. Doppler shift of cometary and atmospheric lines with respect to one another by at least a few A caused by the orbiting velocity of the comet would be sufficient to allow for high transmission measurements. Though long integration time measurements with Lock-In- Amplifier technique have been carried out, no signals from the CH4-rotational lines of the comet coma could be detected. Using the planet Venus as a calibration source for the photon flux and as a result of delicate laboratory measnrements an upper limit ofcould be derived. This value is several orders of magnitude less than the original predictions for Kohoutek during close approach. Therefore, one could conclude that volatile components like CH4 boiled off the comet well before perihelion, at large (~4 AU) distances from the sun and were responsible for the high brightness of the comet at that time. Such a fractionation is only possible if the nucleus was composed of relatively loose, porous ice, rather than compact ice. This hypothesis was strongly supported by the second experiment for search of H2 in the near infrared at the 182 cm telescope of Asiago. Also in this case a Fabry-Perot tilting filter photometer was designed to match with the f/9 optics of the telescope. The instrument (2) consists in a high resolution (~0.7A) tilting filter system with photon counting technique which allows phase-sensitive background subtraction. On the basis of the best data achieved between January 10 and 15 the occurrence of H2-lines with an intensity larger than 2% of the continuum could be excluded, viz. the flux averaged over the field of view was less than 4.105 photons/cm2 sec sr A. Since the pre- and post-perihelion measurements were not affected by molecular fluorescence, they represent only the light scattering flux from dust particles. The data display that the comet's dust coma was definitely brighter during approach than during recession from the sun. However, the quantity of more fundamental interest is the difference in dust production rates, and a derivation of the mass-production rate of dust could be derived. The study shows that both the dust and gas production rate differ greatly in the pre-perihelion period as compared to the post-perihelion period, as conjectured previously for "virgin" comets. (Dust production rate/gas production rate: pre-perihelion 0.1, post-perihelion 1). The pronounced asymmetry in the production rates strongly suggests that fractionation and dust entrainment effects have to be considered in brightness predictions of young comets, the nucleus of which will generally consist of a multi-component mixture of parent molecules.

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Ultraviolet to Near Infrared Observations of BF Cyg

International Astronomical Union Colloquium ◽

10.1017/s0252921100103720 ◽

1988 ◽

Vol 103 ◽

pp. 301-302

Author(s):

A. Cassatella ◽

R. Gonzalez-Riestra ◽

T. Fernandez-Castro ◽

J. Fuensalida ◽

A. Gimenez

Keyword(s):

Canary Islands ◽

Near Infrared ◽

Single Channel ◽

Photon Counting ◽

Optical Observations ◽

Counting System ◽

Infrared Observations ◽

Isaac Newton ◽

Preliminary Results ◽

La Palma

In this paper we provide preliminary results of multifrequency observations of BF Cyg carried out in July 1986. The ultraviolet spectra were obtained on July 26, 1986 using the IUE satellite. The optical observations were made at the Observatorio del Roque de los Muchachos (La Palma, Canary Islands) in July 1986 during the night 13/14 using the Isaac Newton 2.5m telescope with the Intermediate Dispersion Spectrograph (IDS, 500 mm camera) and the Image Photon Counting System (IPCS). The infrared observations were made during the night 13/14 of July, 1986, at the Observatorio del Teide (Tenerife, Canary Islands) using the Carlos Sanchez 1.5m telescope and an infrared single-channel photometer with an InSb detector.

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The Gas Production Rate of Comet Bennett

International Astronomical Union Colloquium ◽

10.1017/s0252921100500992 ◽

1976 ◽

Vol 25 (Part1) ◽

pp. 323-329 ◽

Cited By ~ 1

Author(s):

C. F Lillie ◽

H. U. Keller

Keyword(s):

Production Rate ◽

Heliocentric Distance ◽

Gas Production ◽

Production Rates ◽

Water Vaporization

Comet Bennett (1970 II) was observed with the ultraviolet photometers on OAO-2 from April 13.39 to May 13.88, 1970, while its heliocentric distance increased from R = 0.77 to 1.26 a.u. An analysis of the photometer data for the emission features of OH λ 3090 and H λ1216 indicates the production rates of OH and H were 2.0 x 1029 molecule sec-1 and 5.4 x 1029 atom sec-1, respectively, at R = 1 a.u During this period the production rates of H and OH varied as R-2.3 . This is consistent with the assumption that water vaporization controls the production rate of gas in comets at small heliocentric distances.

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Spectroscopic study of Ceres' collisional family candidate members: taxonomic classification and comparison to Ceres' surface.

10.5194/epsc2021-524 ◽

2021 ◽

Author(s):

Fernando Tinaut-Ruano ◽

Julia de Leon ◽

Eri Tatsumi ◽

Batiste Rousseau ◽

Juan Luis Rizos

Keyword(s):

Near Infrared ◽

Asteroid Belt ◽

Space Weathering ◽

Spectral Slope ◽

Dynamical Study ◽

Royal Astronomical Society ◽

La Palma ◽

The Family ◽

Visible Spectra ◽

Main Asteroid Belt

Despite the observed signs of large impacts on the surface of Ceres, there is no confirmed collisional family associated with this dwarf planet. Carruba et al. (2016) carried out a dynamical study in the &#8216;pristine region&#8217; of the main asteroid belt and proposed a sample of 156 asteroids as candidates to be members of a Ceres&#8217; collisional family. Our main objective in this work is to study the spectral link between Ceres and a total of 14 observed asteroids among the family candidate samples proposed by Carruba et al. (2016) to explore their potential membership to the collisional family. For this aim we obtained visible spectra of these 14 asteroids using the OSIRIS spectrograph at the 10.4m Gran Telescopio de Canarias (GTC), located at the El Roque de los Muchachos Observatory (La Palma, Spain), managed by the Instituto de Astrof&#237;sica de Canarias (IAC). We reduced the raw images and extracted the spectra with a semi-automatic Python-based pipeline. After that, we computed spectral slopes in two different wavelength ranges: one in the visible (490-800 nm) and one in the visible-near-infrared (800-920 nm) to compare the obtained values with those in Ceres&#8217; surface already Ncomputed by Rousseau et al. (2020) using the spectrometer onboard the NASA Dawn spacecraft. We present the spectra and the taxonomy of 14 observed asteroids, their taxonomy, and calculated slopes. We concluded that only one asteroid could be compatible with an origin in a primitive collision at Ceres. We have also found a hydration band at 700 nm, also found in the surroundings of crater Occattor (Rizos et al. 2019). On the other hand, we have also found a relation between the spectral slope of the craters in Ceres&#8217; surface and their age in both wavelength ranges. This behavior could be related to space weathering. Exploring the sample as a whole, the variability in member&#8217;s taxonomy and the differences in their spectral slopes makes us conclude that they cannot be considered as members of a collisional family of Ceres. However, the presence of a hydration band in one of the asteroids could be proof that such a family may have existed. &#160; &#160; Bibliography: Carruba, V., Nesvorn&#253;, D., Marchi, S., & Aljbaae, S. 2016, Monthly Notices of the Royal Astronomical Society, 458, 1117 Rousseau, B., De Sanctis, M. C., Raponi, A., et al. 2020, A&A, 642, A74 Rizos, J. L., de Le&#243;n, J., Licandro, J., et al. 2019, Icarus, 328, 69

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Dry chip feedrate control using online chip moisture

TAPPI Journal ◽

10.32964/tj17.05.295 ◽

2018 ◽

Vol 17 (05) ◽

pp. 295-305

Author(s):

Wesley Gilbert ◽

Ivan Trush ◽

Bruce Allison ◽

Randy Reimer ◽

Howard Mason

Keyword(s):

Production Rate ◽

Control Strategy ◽

Rate Control ◽

Near Infrared ◽

Dry Mass ◽

The Other ◽

Process Variability ◽

Moisture Sensor ◽

Feedback Control Strategy ◽

And Control

Normal practice in continuous digester operation is to set the production rate through the chip meter speed. This speed is seldom, if ever, adjusted except to change production, and most of the other digester inputs are ratioed to it. The inherent assumption is that constant chip meter speed equates to constant dry mass flow of chips. This is seldom, if ever, true. As a result, the actual production rate, effective alkali (EA)-to-wood and liquor-to-wood ratios may vary substantially from assumed values. This increases process variability and decreases profits. In this report, a new continuous digester production rate control strategy is developed that addresses this shortcoming. A new noncontacting near infrared–based chip moisture sensor is combined with the existing weightometer signal to estimate the actual dry chip mass feedrate entering the digester. The estimated feedrate is then used to implement a novel feedback control strategy that adjusts the chip meter speed to maintain the dry chip feedrate at the target value. The report details the results of applying the new measurements and control strategy to a dual vessel continuous digester.

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An Infrared Microscope for Use on a Focused Ion Beam for Circuit Edit and Backside Edit Applications

ISTFA 2015: Conference Proceedings from the 41st International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2015p0097 ◽

2015 ◽

Author(s):

Alexander Richards ◽

Matthew Weschler ◽

Michael Durller

Keyword(s):

Focused Ion Beam ◽

Near Infrared ◽

Ion Beam ◽

Visible Spectrum ◽

Camera System ◽

Buried Structures ◽

Ir Camera ◽

Area Of Interest ◽

Near Ultraviolet ◽

Infrared Microscope

Abstract To help solve the navigational problem, i.e., being able to successfully locate a circuit for probing or editing without destroying chip functionality, a near-infrared (NIR), near-ultraviolet (NUV), and visible spectrum camera system was developed that attaches to most focused ion beam (FIB) or scanning electron microscope vacuum chambers. This paper reviews the details of the design and implementation of the NIR/NUV camera system, as instantiated upon the FEI FIB 200, with a particular focus on its use for the visualization of buried structures, and also for non-destructive real time area of interest location and end point detection. It specifically considers the use of the micro-optical camera system for its benefit in assisting with frontside and backside circuit edit, as well as other typical FIB milling activities. The quality of the image obtained by the IR camera rivals or exceeds traditional optical based imaging microscopy techniques.

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A Comparison of the Near‐Infrared and Visible Spectra of Three Bright Cepheids

The Astrophysical Journal ◽

10.1086/303997 ◽

1997 ◽

Vol 480 (2) ◽

pp. 767-776 ◽

Cited By ~ 10

Author(s):

R. Paul Butler ◽

Roger A. Bell

Keyword(s):

Near Infrared ◽

Visible Spectra

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Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

International Astronomical Union Colloquium ◽

10.1017/s0252921100043645 ◽

1997 ◽

Vol 163 ◽

pp. 725-726

Author(s):

K.-W. Hodapp ◽

E. F. Ladd

Keyword(s):

Near Infrared ◽

Spectral Energy Distribution ◽

Far Infrared ◽

Point Sources ◽

Spectral Energy ◽

Infrared Observations ◽

Circumstellar Material ◽

Dense Cores ◽

Wavelength Radiation ◽

Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

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Spectroscopic detection of forest diseases: a review (1970–2020)

Journal of Forestry Research ◽

10.1007/s11676-021-01378-w ◽

2021 ◽

Author(s):

Lorenzo Cotrozzi

Keyword(s):

Early Detection ◽

Optical Sensors ◽

Near Infrared ◽

Sustainable Forest Management ◽

Visible Spectrum ◽

Cost Effective ◽

Infrared Region ◽

Forest Disturbances ◽

Effective Manner ◽

Forest Diseases

AbstractSustainable forest management is essential to confront the detrimental impacts of diseases on forest ecosystems. This review highlights the potential of vegetation spectroscopy in improving the feasibility of assessing forest disturbances induced by diseases in a timely and cost-effective manner. The basic concepts of vegetation spectroscopy and its application in phytopathology are first outlined then the literature on the topic is discussed. Using several optical sensors from leaf to landscape-level, a number of forest diseases characterized by variable pathogenic processes have been detected, identified and quantified in many country sites worldwide. Overall, these reviewed studies have pointed out the green and red regions of the visible spectrum, the red-edge and the early near-infrared as the spectral regions most sensitive to the disease development as they are mostly related to chlorophyll changes and symptom development. Late disease conditions particularly affect the shortwave-infrared region, mostly related to water content. This review also highlights some major issues to be addressed such as the need to explore other major forest diseases and geographic areas, to further develop hyperspectral sensors for early detection and discrimination of forest disturbances, to improve devices for remote sensing, to implement long-term monitoring, and to advance algorithms for exploitation of spectral data. Achieving of these goals will enhance the capability of vegetation spectroscopy in early detection of forest stress and in managing forest diseases.

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