The Asiago Database on Photometric Systems (ADPS) and the Design of the GAIA Photometric System

The Asiago Database on Photometric Systems (ADPS) is a compilation of basic information and reference data on 201 photometric systems (both ground-based and space-born), available in book format (Moro and Munari, 2000) and electronically (http://ulisse.pd.astro.it/ADPS). It is a relevant source of information to address the legacy of existing photometric systems to the one being designed for the GAIA mission. Its use in such a context and the planned developments are briefly discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Long-term V(RI)_c CCD photometry of pre-main-sequence stars in the association Cepheus OB3

Results from optical CCD photometric observations of 13 pre-main-sequence stars collected during the period from February 2007 to November 2020 are presented. These stars are located in the association Cepheus OB3, in the field of the young star V733 Cephei. Photometric observations, especially concerning the long-term variability of the stars, are missing in the literature. We present the first longterm V(RI)_c monitoring for them, that cover 13 years. Results from our study indicate that all of the investigated stars manifest strong photometric variability. The presented paper is a part of our program for the photometric study of pre-main-sequence stars located in active star-forming regions.     

Study of photometric phase curve: assuming a cellinoid ellipsoid shape for asteroid(106) Dione

We carried out new photometric observations of asteroid(106) Dione at three apparitions(2004, 2012 and 2015) to understand its basic physical properties. Based on a new brightness model,new photometric observational data and published data of(106) Dione were analyzed to characterize the morphology of Dione's photometric phase curve. In this brightness model, a cellinoid ellipsoid shape and three-parameter(H, G_1, G_2) magnitude phase function system were involved. Such a model can not only solve the phase function system parameters of(106) Dione by considering an asymmetric shape of an asteroid, but also can be applied to more asteroids, especially those without enough photometric data to solve the convex shape. Using a Markov Chain Monte Carlo(MCMC) method, Dione's absolute magnitude of H = 7.66_(-0.03)~(+0.03) mag, and phase function parameters G_1= 0.682_(-0.077)~(+0.077) and G_2= 0.081_(-0.042)~(+0.042) were obtained. Simultaneously, Dione's simplistic shape, orientation of pole and rotation period were also determined preliminarily.     

A visible and near-infrared photometric correction for Moon Mineralogy Mapper (M3)

Observations of the Moon obtained by the Moon Mineralogy Mapper (M³) instrument were acquired at various local viewing geometries. To compensate for this, a visible near-infrared photometric correction for the M³ observations of the lunar surface has been derived. Images are corrected to the standard geometry of 30° phase angle with an incidence of 30° and an emission of 0°. The photometric correction is optimized for highland materials but is also a good approximation for mare deposits. The results are compared with ground-based observations of the lunar surface to validate the absolute reflectance of the M³ observations. This photometric model has been used to produce the v1.0 Level 2 delivery of the entire set of M³ data to the Planetary Data System (PDS). The photometric correction uses local topography, in this case derived from an early version of the Lunar Orbiter Laser Altimeter data, to more accurately determine viewing geometry. As desired, this photometric correction removes most of the topography of the M³ measurements. In this paper, two additional improvements of the photometric modeling are discussed: (1) an extrapolated phase function long ward of 2500 nm to avoid possible misinterpretation of spectra in the wavelength region that includes possible OH/H₂O absorptions and (2) an empirical correction to remove a residual cross-track gradient in the data that likely is an uncorrected instrumental effect. New files for these two effects have been delivered to PDS and can be applied to the M³ observations.     

Magnetic,chemically peculiar (CP2) stars in the SuperWASP survey

The magnetic chemically peculiar (CP2) stars of the upper main sequence are well‐suited for investigating the impact of magnetic fields on the surface layers of stars, which leads to abundance inhomogeneities (spots) resulting in photometric variability. The light changes are explained in terms of the oblique rotator model; the derived photometric periods thus correlate with the rotational periods of the stars. CP2 stars exhibiting this kind of variability are classified as α² Canum Venaticorum (ACV) variables. We have analysed around 3850000 individual photometric WASP measurements of magnetic chemically peculiar (CP2) stars and candidates selected from the catalogue of Ap, HgMn, and Am stars, with the ultimate goal of detecting new ACV variables. In total, we found 80 variables, from which 74 are reported here for the first time. The data allowed us to establish variability for 23 stars which had been reported as probably constant in the literature before. Light curve parameters were obtained for all stars by a least‐squares fit with the fundamental sine wave and its first harmonic. Because of the scarcity of Strömgren uvbyβ measurements and the lack of parallax measurements with an accuracy better than 20%, we are not able to give reliable astro‐physical parameters for the investigated objects. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Photometrische Untersuchungen im Zentralgebiet der Praesepe (NGC 2632)

In supplementing the photometric sequence in the central part of the Praesepe cluster and its extension to fainter stars a photographic photometry in UBV on plates of the 134/200/400 cm – Schmidt telescope of Karl-Schwarzschild-Observatory was done. The already known photometric data from stars obtained by HAFFNER , HECKMANN and WEIS were completed by (U – B) colours on the base of JOHNSON'S photoelectric photometry. Besides, a number of brighter and fainter stars, cluster members, white dwarfs inclusively and field stars were investigated to set up a photometric sequence down to V ≈ 18.^m9. A finding chart where all the measured stars are marked is given.     

Results of the Photometric Observations of the NEA (2100) Ra-Shalom During an Encounter in 2019

Solar System Research - This paper presents the results of the photometric CCD observations of the NEA (2100) Ra-Shalom carried out on August 24–29, 2019, at the 1-m telescope of the Sanglokh...     

The pulsating hydrogen-deficient star LSS 3184 (BX Cir)

We present extensive photometry and spectroscopy of the extremely hydrogen-deficient star, LSS 3184, recently discovered to be a rapid variable (period ∼0.1066 d) strikingly similar to V652 Her. Over 95 h of photometry confirms the reported variability, which is of rather low amplitude (Δ V ∼0.03 mag), defines the light curve with greater precision and establishes a much more accurate ephemeris (period ∼0.106 578 4 d) to form a basis for detecting period change. Attention is drawn to the usefulness of a period-finding technique that fits harmonic components to the photometric observations. Spectroscopy shows a peak-to-peak variation in radial velocity of about 30 km s⁻¹, which, when combined with the photometric observations, confirms the pulsational nature of the variability and strongly indicates that the pulsations are radial in nature.     

Initial Calibration of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO)

The Atmospheric Imaging Assembly (AIA) instrument onboard the Solar Dynamics Observatory (SDO) is an array of four normal-incidence reflecting telescopes that image the Sun in ten EUV and UV wavelength channels. We present the initial photometric calibration of AIA, based on preflight measurements of the response of the telescope components. The estimated accuracy is of order 25%, which is consistent with the results of comparisons with full-disk irradiance measurements and spectral models. We also describe the characterization of the instrument performance, including image resolution, alignment, camera-system gain, flat-fielding, and data compression.     

Measurements of the Gegenschein brightness from the Solar Mass Ejection Imager (SMEI)

The Gegenschein is viewed by the Solar Mass Ejection Imager (SMEI), which has provided near-full-sky broadband visible-light photometric maps for over 5 years. These have an angular resolution of about 0.5° and differential photometric stability of about 1% throughout this time. When individual bright stars are removed from the maps and an empirical sidereal background subtracted, the residue is dominated by the zodiacal light. The unprecedented sky coverage and duration of these measurements enables a definitive characterization of the Gegenschein. This article describes the analysis method for these data, presents a movie with time of the Gegenschein brightness distribution, determines empirical formulae describing its average shape, and discusses its variation with time. These measurements unambiguously confirm previous reports that the Gegenschein surface-brightness distribution has a decided peak in the antisolar point, which rises above a broader background.     

Astrometry and photometry of asteroid (308635) 2005 YU55

Astrometric and photometric observations of asteroid (308635) 2005 YU55 were carried out at the computer-aided ZA-320M and MTM-500M telescopes of the Pulkovo observatory in the period of its closest approach to the Earth, from November 9 to 20, 2011. The new orbit of the asteroid changed after its close approach to the Earth was determined. From this orbit, a close approach to Venus on January 19, 2029, was precalculated, and the distance at the closest approach—359000 km—was estimated. From the analysis of the acquired photometric data, the axial rotation period of the asteroid was more accurately determined, and it amounted to 16.3 ± 0.4 h. The color indexes of the asteroid, B-V, V-R, and R-I, were estimated, which allowed the taxonomic class of the asteroid, B, to be determined from them. In addition, from our photometric observations of the asteroid, the earlier unknown change in its brightness with a period of 0.9–1.2 h was detected; the cause of this change has not been completely studied yet.     

Photometric and spectroscopic variability of the pre‐main sequence star V1184 Tauri (CB 34V)

We present recent results from optical photometric and spectroscopic observations of the pre‐main sequence star V1184 Tau (CB 34V). The star is associated with the Bok globule CB 34 and was considered as a FUOR candidate in previous studies. Our photometric data obtained from October 2000 to April 2003 show that the stellar brightness varies with an amplitude of about 0.m 5 (I ), but from August 2003 the photometric behavior of the star has changed dramatically. Three deep brightness minima (ΔI ∼ 4^m.2) were observed during the past two years. The analysis of available photometric data suggests that V1184 Tau shows two types of variability produced (1) by rotation of large cool spotted surface and (2) by occultation from circumstellar clouds of dust or from features of a circumstellar disk. The behavior of the V – I index indicates that the star becomes redder towards minimum light, but from a certain turning point (V ∼ 18^m.2) it gets bluer and is fading further. Five medium dispersion optical spectra of V1184 Tau were obtained in the period 2001–2004. Signi.cant changes in the profile and strength of the emission lines in the spectrum of V1184 Tau were found. During minimum light the equivalent width of the Hα emission line increases from 4 Å to 9 Å. The [O I] lines (λλ 6003, 6363 Å) are also seen in emission while the sodium doublet keeps its absorption strength and equivalent width. The possibility to reconstruct the historical light curve of V1184 Tau using photographical plate archives is brie.y discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Determination of rotational parameters of asteroid (360) Carlova

Information on the rotational parameters of asteroids may provide data for research on the collision and evolution of asteroids, or even the evolution of the solar system. We carried out new CCD photometric observation of the main belt carbon-type asteroid (360) Carlova with the 1-m telescope of Yunnan Observatory, and obtained the following results:. rotational sidereal period, 0.25780417 ± 0.00000003d, ecliptic coordinates of the rotating axis, (95°±3°, 40°±1°). These are found by using the epoch-method of retrieval with our and previously published photometric data. Our results are consistent with those of our predecessors, while being slightly more accurate.     

An analysis of close binaries (CB) based on photometric measurements (IV)

The paper is devoted to the actual problematics in the determination of orbital and physical parameters of active CB on the basis of the interpretation of photometric observations. One solves the problem in two stages: by obtaining a synthetic light curve in the case when the parameters of the corresponding CB model are given a priori (direct problem) and by determining the parameters of the given model for which the best fit between the synthetic light curve and the observations is achieved (inverse problem). In this paper, the above procedure is applied to a particular case of CB AG Vir.     

Global photometric properties of Asteroid (4) Vesta observed with Dawn Framing Camera

Dawn spacecraft orbited Vesta for more than one year and collected a huge volume of multispectral, high-resolution data in the visible wavelengths with the Framing Camera. We present a detailed disk-integrated and disk-resolved photometric analysis using the Framing Camera images with the Minnaert model and the Hapke model, and report our results about the global photometric properties of Vesta. The photometric properties of Vesta show weak or no dependence on wavelengths, except for the albedo. At 554 nm, the global average geometric albedo of Vesta is 0.38 ± 0.04, and the Bond albedo range is 0.20 ± 0.02. The bolometric Bond albedo is 0.18 ± 0.01. The phase function of Vesta is similar to those of S-type asteroids. Vesta’s surface shows a single-peaked albedo distribution with a full-width-half-max ∼17% relative to the global average. This width is much smaller than the full range of albedos (from ∼0.55× to >2× global average) in localized bright and dark areas of a few tens of km in sizes, and is probably a consequence of significant regolith mixing on the global scale. Rheasilvia basin is ∼10% brighter than the global average. The phase reddening of Vesta measured from Dawn Framing Camera images is comparable or slightly stronger than that of Eros as measured by the Near Earth Asteroid Rendezvous mission, but weaker than previous measurements based on ground-based observations of Vesta and laboratory measurements of HED meteorites. The photometric behaviors of Vesta are best described by the Hapke model and the Akimov disk-function, when compared with the Minnaert model, Lommel–Seeliger model, and Lommel–Seeliger–Lambertian model. The traditional approach for photometric correction is validated for Vesta for >99% of its surface where reflectance is within ±30% of global average.     

Negative detection of the four-hour periodicity of the central star of M1-2 (VV8)

Four-hour (4.0002 hr) binary periodicity of the emission-line object M1-2 (=VV8), claimed by Drummond (1980), is examined on the basis of photometric and spectroscopic observations. However, neither positive variation of the light nor that of the radial velocity associated with that period has been found.     

On nova Scorpii 2007 N.1 (V1280 Sco)

We present the results of our photometric and spectroscopic observations of Nova Sco 2007 N.1 (V1280 Sco). The photometric data was represented by a single data point in the light curve since the observation was carried out only for one night. The spectra cover two different phases of the object’s evolution during the outburst, i.e. pre-maximum and post-maximum. Measurements of the P-Cygni profile on Na I ‘D’ line (5889 Å) was derived as the velocity of shell expansion, yielding 1567.43±174.14 km s^?1. We conclude that V1280 Sco is a fast Fe II-type nova.     

Observation Plan for Refining Shape Model of (6) HEBE

As the number of observatories located on the surface of Earth is increasing largely in decades more and more photometric data of asteroids is observed to make the research about their various physical and chemical characteristics. Compared with hundreds of thousands of asteroids found up to now, rare hundreds of three-dimensional shape models of asteroids have been built from the tremendous photometric data with incessant observations, i.e. lightcurves. For some specific asteroid already with many observed lightcurves, the unceasing observation is not too much valuable, nevertheless an additional lightcurve observed in a request viewing aspect can refine the shape model and other related parameters. This article taking the asteroid (6) HEBE for example, attempts to introduce a method to make the observation plan by combining the request of the shape model and the orbital limitation of asteroids. Through analyzing the distribution of lightcurves of (6) HEBE, small cabins without any lightcurve data are found, which can be filled by new observations at some specified dates when the positions of Asteroid, Sun, Earth are limited as the request geometry.     

Photometric investigations of distant comets C/2002 VQ94 (LINEAR) and 29P/Schwassmann-Wachmann-1

We present an analysis of the results of photometric investigations of two distant comets, C/2002 VQ94 (LINEAR) and 29P/Schwassmann-Wachmann-1, obtained with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The comets under study demonstrate sufficient activity out of the zone of water ice sublimation (at heliocentric distances longer than 5 AU). In the spectra of the investigated comets, we found the CO⁺ and N₂⁺ emission. The presence of this emission may say that the comets were formed in the outer parts of the Solar System, in a protoplanetary cloud at a temperature ≤25 K. We found that the photometric maximum of the ionosphere (in the CO⁺ filter) of the comet C/2002 VQ94 (LINEAR) is shifted relative to the photometric center of the dust coma by 1.4″ (7.44 × 10³ km) in the direction deflected by 63° from the direction to the Sun. Using special filters to process the images, we picked out active structures (jets) in the dust coma of the 29P/Schwassmann-Wachmann-1 comet.     

Photometric Investigation of the Peculiar Galaxy NGC 7468 (Mrk 314)

The results of a photometric investigation of the peculiar galaxy NGC 7468 are presented. Based on its integrated characteristics, NGC 7468 is a relatively small galaxy of a late morphological type, resembling the Large Magellanic Cloud (LMC). The differences of NGC 7468 from the LMC (bluer color indices, an increased luminosity, an increased H I abundance, and strong emission in the FIR range) may be related to a higher rate of star formation in it. The increased star-forming activity in the central regions of NGC 7468 and its other properties may be related to a gravitational interaction with a small neighboring galaxy, the remnants of which are now observed as a companion.