Results 141 to 150 of about 146,804 (365)
UBVRI photometric comparison sequences for symbiotic stars [PDF]
, 2000 We present accurate UBVRI photometric comparison sequences around 20 symbiotic stars. The sequences extend over wide brightness and color ranges, and are suited to cover quiescence as well as outburst phases. The sequences are intended to assist both present time photometry as well as measurement of photographic plates from historical archives.
arxiv +1 more source
Symbiotic Nova PU Vul - 33 Years of Observations
Open Astronomy, 2012 We present UBVRI light curves of the symbiotic nova PU Vul after its outburst in 1978. Three observed eclipses of the hot component by the cool one were used to determine the ephemeris of the binary system as JD (Min I) = 2444550(15) + 4897(10) × E days.
Shugarov S., Chochol D., Kolotilov E.
doaj +1 more source
The Slow‐Rotating Nucleus of Comet C/2013 R1 (Lovejoy)
Astronomische Nachrichten, EarlyView.ABSTRACT The close approach of comet C/2013 R1 (Lovejoy) allowed us to conduct an in‐depth study of the morphology of the inner coma. From the measurement of the dust emission structures expanding near the cometary nucleus in November–December 2013, we derived a slow rotation period of 47.8±1.2$$ 47.8\pm 1.2 $$ h.
Federico Manzini +12 more
wiley +1 more source
Ultraviolet Passbands for a Space Multicolor Photometric System
Open Astronomy, 2003 The results of search for the optimal location of ultraviolet passbands for an extra-atmospheric photometric system are given. The addition of passbands near the well-known extinction bump at 218 nm to the photometric system makes it possible to ...
Ambartsoumian A. R. +2 more
doaj +1 more source
Astronomische Nachrichten, EarlyView.ABSTRACT Classification of galaxies, stars, and quasars using spectral data is fundamental to astronomy, but often relies heavily on redshift. This study evaluates the performance of 10 machine learning algorithms on SDSS data to classify these objects, with a particular focus on scenarios where redshift information is unavailable.
Debashis Chatterjee, Prithwish Ghosh
wiley +1 more source
Interstellar Extinction in the Direction of The Barnard 1 Dark Cloud in Perseus
Open Astronomy, 2003 Spectral and luminosity classes, absolute magnitudes, color excesses, interstellar extinctions and distances are determined for 98 stars down to 18 mag in the Barnard 1 dark cloud belonging to the Per OB2 association. The classification of stars is based
Černis K., Straižys V.
doaj +1 more source
Color Photometric Stereo Using Multi-Band Camera Constrained by Median Filter and Occluding Boundary
Journal of Imaging, 2019 One of the main problems faced by the photometric stereo method is that several measurements are required, as this method needs illumination from light sources from different directions.
Daisuke Miyazaki +2 more
doaj +1 more source
Photometric Redshifts of Galaxies in the Hubble Deep Field [PDF]
arXiv, 1997 We describe our application of broad-band photometric redshift techniques to faint galaxies in the Hubble Deep Field. To magnitudes AB(8140) < 26, the accuracy of the photometric redshifts is a few tenths and the reliability of the photometric redshifts approaches 100%. At fainter magnitudes the effects of photometric error on the photometric redshifts
arxiv
A Slowly Pulsating Run‐Away B Star at High Galactic Latitude Ejected From a Spiral Arm
Astronomische Nachrichten, EarlyView.ABSTRACT We report the discovery of the young B6 V run‐away star LAMOST J083323.18 + 430825.4, 2.5 kpc above the Galactic plane. Its atmospheric parameters and chemical composition are determined from LAMOST spectra, indicating normal composition. Effective temperature (Teff$$ {T}_{\mathrm{eff}} $$ = 14,500$$ \mathrm{14,500} $$ K) and gravity (logg ...
Ulrich Heber +3 more
wiley +1 more source
The Photophysics of Nucleic Acids: Consequences for the Emergence of Life
ChemSystemsChem, Volume 5, Issue 1, January 2023., 2023 Photochemical reactions in nucleic acids induced by ultraviolet (UV) radiation could have played an important role in the prebiotic selection of the building blocks of life. This Review summarizes the quantum efficiencies of the photorelaxation pathways of nucleic acids and discusses its implications for the emergence of an initial sequence pool on ...
Corinna L. Kufner +2 more
wiley +1 more source