105,723 research outputs found
Unusual polarimetric properties for interstellar comet 2I/Borisov
No full textSo far, only two interstellar objects have been observed within our Solar System. While the first one, 1I/‘Oumuamua, had asteroidal characteristics, the second one, 2I/Borisov, showed clear evidence of cometary activity. We performed polarimetric observations of comet 2I/Borisov using the European Southern Observatory Very Large Telescope to derive the physical characteristics of its coma dust particles. Here we show that the polarization of 2I/Borisov is higher than what is typically measured for Solar System comets. This feature distinguishes 2I/Borisov from dynamically evolved objects such as Jupiter-family and all short- and long-period comets in our Solar System. The only object with similar polarimetric properties as 2I/Borisov is comet C/1995 O1 (Hale-Bopp), an object that is believed to have approached the Sun only once before its apparition in 1997. Unlike Hale-Bopp and many other comets, though, comet 2I/Borisov shows a polarimetrically homogeneous coma, suggesting that it is an even more pristine object.This work is based on observations made with ESO Telescopes at the La Silla Paranal Observatory thanks to Director Discretionary Time under programme ID 2104.C-5003. The work of T.S.-R. was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE)
Cometary observations in light-polluted environments: a case study of interstellar comet 2I/Borisov
No full textComets and asteroids have long captured human curiosity, and until recently, all documented examples belonged to our Solar System. That changed with the discovery of the first known interstellar object, 1I/2017 U1 (‘Oumuamua), in 2017. Two years later, on August 30, 2019, Gennady Borisov discovered a second interstellar object, 2019 Q4, which was officially designated 2I/Borisov. From its initial images, the object’s diffuse appearance hinted at its cometary nature. To better understand the photometric evolution of comet 2I/Borisov as it traveled through the inner Solar System, we compiled observations using medium-sized telescopes. This data is crucial for gaining insights into its size and composition, as well as how such objects, after millions of years in interstellar space, behave when exposed to the Sun’s radiation. Given that 2I/Borisov is the first interstellar comet ever observed, constraining its behavior is of great scientific interest. In this paper, we present photometric data gathered from observatories in Crimea and Catalonia, highlighting the importance of systematic photometric studies of interstellar objects using meter-class telescopes. Our observations showed a steady increase in the comet’s brightness as it approached perihelion, likely due to the slow sublimation of ices. Over the five-month pre-perihelion observation period, we did not detect any significant changes in magnitude. The analysis of observations reveals a steady increase in comet 2I/Borisov brightness as it approached perihelion, likely due to the sublimation of ices, with no observable outbursts during the five-month pre-perihelion period. Additionally, we discuss the challenges in ground-based observation of comets posed by light pollution today, particularly in urban areas, where visual observations are severely limited. Using sample surface brightness measurements, we demonstrate the impact of light pollution and outline the importance of systematic photometric studies for interstellar objects.We acknowledge support from the Spanish Ministry of Science and Innovation, research projects PGC2018-097374-B-I00 and PID2021-128062NB-I00 (PI: JMTR), funded by FEDER/Ministerio de Ciencia e Innovación – Agencia Estatal de Investigación, the Academy of Finland project no. 325806 “PlanetS” (PI: MG), and the Centre for Innovation and Transfer of Natural Sciences and Engineering Knowledge, University of Rzeszów, Poland (RPPK.01.03.00-18-001/10-00). The programme of development within Priority-2030 is acknowledged for supporting the research at UrFU. We thank Herbert Raab for his kind support with Astrometrica software. We also thank the feedback received from A. Fraser Gillan. TJO images at OAdM were scheduled by Toni Santana (UB).Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Peer reviewe
Research data supporting "Nonlinear Optical Response of a Plasmonic Nanoantenna to Circularly Polarized Light: Rotation of Multipolar Charge Density and Near-Field Spin Angular Momentum Inversion"
No full textWe include the dataset corresponding to the figures of the paper "Nonlinear Optical Response of a Plasmonic Nanoantenna to Circularly Polarized Light: Rotation of Multipolar Charge Density and Near-Field Spin Angular Momentum Inversion" by M. Quijada, A. Babaze, J. Aizpurua, and A.G. Borisov, published in the journal ACS Photonics, with DOI: 10.1021/acsphotonics.3c00783 . The set includes data to generate: optical spectra, charge density maps, time evolution of multipolar moments, and all the plots in the paper.Peer reviewe
Homogenization of the planar waveguide with frequently alternating boundary conditions
No full textWe consider the Laplacian in a planar strip with a Dirichlet boundary condition on the upper boundary and with a frequent alternation boundary condition on the lower boundary. The alternation is introduced by the periodic partition of the boundary into small segments on which Dirichlet and Neumann conditions are imposed in turns. We show that under certain conditions the homogenized operator is the Dirichlet Laplacian and prove the uniform resolvent convergence. The spectrum of the perturbed operator consists of its essential part only and has a band structure. We construct the leading terms of the asymptotic expansions for the first band functions. We also construct the complete asymptotic expansion for the bottom of the spectrum
Dust environment model of the interstellar comet 2i/borisov
No full text2I/Borisov is the first interstellar comet discovered on 2019 August 30, and it soon showed a coma and a dust tail. This study reports the results of images obtained at the Telescopio Nazionale Galileo telescope, on La Palma-Canary Islands, in 2019 November and December. The images have been obtained with the R filter in order to apply our dust tail model. The model has been applied to the comet 67P/Churyumov-Gerasimenko and compared to the Rosetta dust measurements showing a very good agreement. It has been applied to the comet 2I/Borisov, using almost the same parameters, obtaining a dust environment similar to that of 67P/Churyumov-Gerasimenko, suggesting that the activity may be very similar. The dust tail analysis provided a dust-loss rate Qd≈ 35 kg s-1in 2019 November and Qd≈ 30 kg s-1in 2019 December
Photometric Follow-Up of Interstellar Comet 2I/ BORISOV Since Its Discovery
No full textTalk delivered in 51st Lunar and Planetary Science Conference in Texas, USA, 16-20 March 2020In this abstract we compile the photometric measurements made of comet Borisov to exemplify the relevance of a systematic photometric study of interstellar visitors using meter-class instruments
Planar waveguide with “twisted” boundary conditions: Small width
No full textWe consider a planar waveguide with "twisted" boundary conditions. By twisting we mean a special combination of Dirichlet and Neumann boundary conditions. Assuming that the width of the waveguide goes to zero, we identify the effective (limiting) operator as the width of the waveguide tends to zero, establishes the uniform resolvent convergence in various possible operator norms, and gives the estimates for the rates of convergence. We show that studying the resolvent convergence can be treated as a certain threshold effect and we present an elegant technique which justifies such point of view. (C) 2012 American Institute of Physics. [doi:10.1063/1.3681895
Planar waveguide with “twisted” boundary conditions: Discrete spectrum
No full textWe consider a planar waveguide with combined Dirichlet and Neumann conditions imposed in a "twisted" way. We study the discrete spectrum and describe it dependence on the configuration of the boundary conditions. In particular, we show that in certain cases the model can have discrete eigenvalues emerging from the threshold of the essential spectrum. We give a criterium for their existence and construct them as convergent holomorphic series. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3670875
Complete asymptotic expansions for eigenvalues of Dirichlet laplacian in thin three-dimensional rods
No full textWe consider the Dirichlet Laplacian in a thin curved
three-dimensional rod. The rod is finite. Its cross-section is
constant and small, and rotates along the reference curve in an
arbitrary way. We find a two-parametric set of the eigenvalues of
such operator and construct their complete asymptotic expansions. We
show that this two-parametric set contains any prescribed number of
the first eigenvalues of the considered operator. We obtain the
complete asymptotic expansions for the eigenfunctions associated
with these first eigenvalues
Research data supporting "Electronic Exciton-Plasmon Coupling in a Nanocavity Beyond the Electromagnetic Interaction Picture"
No full textWe include the dataset corresponding to the figures of the paper "Electronic Exciton−Plasmon Coupling in a Nanocavity Beyond the Electromagnetic Interaction Picture" by A. Babaze, R. Esteban, A.G. Borisov, and J. Aizpurua, published in the journal Nano Letters, with DOI: 10.1021/acs.nanolett.1c03202 . The set includes data to generate: optical spectra, charge and current density maps, projected density of electronic states, and plots in the paper.Peer reviewe
- …
