Interannual variability of the solar constant

Fedorov, V. M.

doi:10.1134/s0038094612020049

Cited by 21 publications

(6 citation statements)

References 3 publications

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“…Compared to the Sun, this is a violent environment for the stability of any planet's atmosphere. The solar constant exhibits variability on the order of several parts per million (e.g., Froehlich 1987;Fedorov 2012), and the variability due to the Earth's noncircular orbit is on the scale of 6%, but over 6 months, not 2 days (Fedorov 2012). In the case of HR 8799, variability of the star is three orders of magnitude greater over a hundred times shorter timescale.…”

Section: Discussion: Planets Are Diversementioning

confidence: 99%

Reconnaissance of the Hr 8799 Exosolar System. I. Near-Infrared Spectroscopy

Oppenheimer

Baranec

Beichman

et al. 2013

ApJ

153

185

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We obtained spectra in the wavelength range λ = 995-1769 nm of all four known planets orbiting the star HR 8799. Using the suite of instrumentation known as Project 1640 on the Palomar 5 m Hale Telescope, we acquired data at two epochs. This allowed for multiple imaging detections of the companions and multiple extractions of low-resolution (R ∼ 35) spectra. Data reduction employed two different methods of speckle suppression and spectrum extraction, both yielding results that agree. The spectra do not directly correspond to those of any known objects, although similarities with L and T dwarfs are present, as well as some characteristics similar to planets such as Saturn. We tentatively identify the presence of CH 4 along with NH 3 and/or C 2 H 2 , and possibly CO 2 or HCN in varying amounts in each component of the system. Other studies suggested red colors for these faint companions, and our data confirm those observations. Cloudy models, based on previous photometric observations, may provide the best explanation for the new data presented here. Notable in our data is that these presumably co-eval objects of similar luminosity have significantly different spectra; the diversity of planets may be greater than previously thought. The techniques and methods employed in this paper represent a new capability to observe and rapidly characterize exoplanetary systems in a routine manner over a broad range of planet masses and separations. These are the first simultaneous spectroscopic observations of multiple planets in a planetary system other than our own.

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Section: Discussion: Planets Are Diversementioning

confidence: 99%

Reconnaissance of the Hr 8799 Exosolar System. I. Near-Infrared Spectroscopy

Oppenheimer

Baranec

Beichman

et al. 2013

ApJ

153

185

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“…The visible light photoreactor was composed of two dichroic lamps, fixed at 21 cm from the hair samples, with an irradiance of 2.0 W cm −2 . The average irradiance of the sunlight is 136.7 mW cm −2 .…”

Section: Methodsmentioning

confidence: 99%

“…This is especially relevant when someone is exposed to the sun at the beach, for example, since the radiant exposure can be quite significant. One hour of direct sun exposition presents a total radiant exposure of 492 J cm −2 , since the normal total surface irradiance of sunlight is 136.7 mW cm −2 . Indeed, 24.5 J cm −2 is the radiant exposure for the UV region for an exposure of 1 h at the beach (6.8 mW cm −2 irradiance), while it is 221.4 J cm −2 in the visible range (61.5 mW cm −2 ).…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy as a tool to evaluate hair damage and protection

Pavani

Severino²,

Santos³

et al. 2018

Intern J of Cosmetic Sci

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OBJECTIVE: Methods that can be used to analyse hair damage and to support a claim of hair protection are important for the cosmetic industry. There are many approaches available, but they are usually laborious and expensive. The researchers propose a simple fluorescence method that is based upon the emissive properties of damaged hair. METHODS: Hair fluorescence was observed when using both fluorimetry and microscopic procedures. The method was developed by comparing native hair with hair that was damaged by UVA and visible light. RESULTS: Spectroscopic properties (absorption and emission) of hair in the visible range are presented. The changes in the emissive properties of hair during irradiation were characterized and they were correlated with photobleaching, which is due to the generation of singlet oxygen. Emissions were also obtained in the hair shafts that had been previously treated with chamomile extract and this treatment was able to avoid hair bleaching. CONCLUSION: The emissive properties of hair in the visible range can be used as a tool for the evaluation of hair damage and protection. This method can be useful as a tool in order to claim substantiation. R esum e OBJECTIF: Les m ethodes pouvantêtre utilis ees pour analyser les dommages caus es aux cheveux et pour soutenir une revendication de protection des cheveux sont importantes pour l'industrie cosm etique. Il existe de nombreuses approches disponibles, mais elles sont g en eralement laborieuses et coûteuses. Les chercheurs proposent une m ethode simple de fluorescence qui repose sur les propri et es emissives de cheveux abîm es. M ETHODES: La fluorescence des cheveux a et e observ ee en utilisant des proc edures de fluorim etrie et de microscopie. La m ethode a et e d evelopp ee par comparaison de cheveux de Br esiliens avec des cheveux endommag es par l'action des UVA et de la lumi ere visible. R ESULTATS: Les propri et es spectroscopiques (absorption et emission) des cheveux dans le domaine visible sont pr esent ees. Les changements dans les propri et es emissives des cheveux au cours de l'irradiation ont et e caract eris es et ont et e corr el es avec le photoblanchiment, qui sont dûs a la g en eration d'oxyg ene singulet. Des emissions ont egalement et e obtenues dans les tiges capillaires pr ec edemment trait es a l'extrait de camomille et ce traitement a pu eviter le blanchiment des cheveux. CONCLUSION: Les propri et es emissives des cheveux dans le visible peutêtre utilis e comme outil d' evaluation des dommages et de la protection des cheveux. Cette m ethode peutêtre utile en tant qu'outil pour une justification des revendications.The chamomile extract, generously provided by Farma Service Bioextract Ltda, was diluted in a hydroglicolic vehicle (HG) to 10% (v/v). The hair shafts were immersed in this solution for 30 min. The excess liquid was removed by absorbent paper and the samples were exposed to photodamage by the ultraviolet or visible light. Processing and the obtention of the hair cross sectionsThe hair strands were embedded with...

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“…However, this question remains debatable (Beer et al, 2000;Foukal et al, 2006;Abdusamatov, 2007;Mackey, 2009: Kopp andLeun, 2011). Another reason is related to celestial mechanical processes (changes in the Earth-Sun dis tance) resulting from the orbital motion of the Earth being perturbed by the nearest celestial bodies (Borisenkov et al, 1985;Fedorov, 2012). During the unperturbed (keplerian) motion of the Earth, the insolation changes within the annual orbital motion of the Earth around the Sun with regular annual variation (maximum is in the perihelion, minimum is in the aphelion).…”

Section: Introductionmentioning

confidence: 99%

“…Studies for calculation of the Earth's insolation were started at A. I. Voeikov Main Geophysical Observa tory; however, there were no further developments (Borisenkov et al, 1983;1985). Currently, such studies are conducted at Lomonosov MSU (Fedorov, 2012;2013;2015). In this paper we assume the following notations for the components of interannual variabil ity of the Earth's insolation.…”

Section: Introductionmentioning

confidence: 99%

Theoretical calculation of the interannual variability of the Earth’s insolation with daily resolution

Fedorov

2016

Sol Syst Res

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Based on the astronomical ephemerides DE 406, theoretical calculations have been performed of the interannual variability of the Earth's insolation related to celestial mechanical processes for 365 points of a tropical year in the time period from 1900 to 2050. It has been determined that the average amplitude of variations of the interannual insolation is 0.310 W/m 2 (0.023% of the solar constant). The calculated varia tions are characterized by strict periodicity that corresponds with the length of a synodic month. Connection between the extreme values of the calculated insolation variability and syzygies has been defined. The average amplitude of the calculated variability exceeds by 1.7 times (0.01% of the solar constant) the amplitude of the interannual variability in the 11 year variation of the total Earth's insolation.

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Interannual variability of the solar constant

Cited by 21 publications

References 3 publications

Reconnaissance of the Hr 8799 Exosolar System. I. Near-Infrared Spectroscopy

Reconnaissance of the Hr 8799 Exosolar System. I. Near-Infrared Spectroscopy

Spectroscopy as a tool to evaluate hair damage and protection

Theoretical calculation of the interannual variability of the Earth’s insolation with daily resolution

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