Photographic Photometry Research Articles

The Old Open Cluster Melotte 66

Photoelectric and photographic photometry of the open cluster Melotte 66 is presented. The CM diagram shows most of the characteristics of an old cluster. The giant branch is broad with its blue edge populated preferentially by stars from the outer parts of the cluster. There is no detectable horizontal subgiant sequence. The main sequence turn-off colour, two-colour diagram and the colour difference between the turn-off and the subgiants are used to estimate the age and composition. Melotte 66 appears to have reddening E(B–V) = 0m.17 and ultraviolet excess |$\delta(U-B) \sim 0^{\text{m}.}1$| corresponding to [Fe/H]⊙ = –0·3. The cluster is probably between 6 and |$7 \times 10^{9}$| yr old. A distance modulus |$(m-M)_{0} = 12^{\text{m}.}4$| is derived, which implies that the cluster lies about 750 pc from the galactic plane.

A Spectrographic survey of 21 planetary nebulae.

view Abstract Citations (58) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A spectrographic survey of 21 planetary nebulae. Kaler, J. B. ; Aller, L. H. ; Czyzak, S. J. Abstract We present a blue spectral survey and coarse photographic photometry for 21 planetary nebulae, of which eight have not been heretofore observed with any detail. We have observed eight of the nebulae photoelectrically. Most of the planetaries studied are of intermediate excitation; five present no detectable He ii lines, and two are of high excitation with powerful He ii A4686. The chief value of the photographic part of the study is to locate objects deserving of further study. We have, however, derived rough electron densities for the nebulae from either or both of the [0 ii] or [Ar iv] doublet ratios, and electron temperatures from the [0 iii] lines. Values are generally within the normal range except for Hb 12, for which Ne may be as high as 4 x 10 . Subject headings: nebulae: planetary - spectrophotometry Publication: The Astrophysical Journal Pub Date: February 1976 DOI: 10.1086/154122 Bibcode: 1976ApJ...203..636K full text sources ADS | data products SIMBAD (24)

Mass-luminosity distribution and physical conditions of ionized gas in NGC 4575

Photographic photometry and spectroscopic observations of NGC 4575 suggest it to be a galaxy of reduced dimensionsD×d=14.4×13.5 kpc and of high luminosityM=−20.7. The rotation curve was also determined. Assuming a model of three homogeneous similar spheroids, we derived the density and mass distribution, and their total mass was found to be ℳ T =2.33 × 1010ℳ.

Photographic photometry of the asteroid 291 Alice

During its 1974 opposition the asteroid 291 Alice was observed photographically with the Schmidt telescope at the Kvistaberg Observatory. This article describes the reduction method of the iris readings. The synodic period of 291 Alice is found to be 4 h 18 m ̇ 9 and the amplitude of the light curves 0 m ̇ 25.

INTERMEDIATE- AND WIDE-BAND PHOTOMETRY OF NGC 6025.

ABSTRACT The uvby photoelectric photometry and UBV photographic photometry of NGC 6025 have yielded a distance modulus of 9.7 j 0.1 and an age of 90 million years. No major deviation from a normal interstellar reddening law has been noted. A gap in the (B- V) distribution of stars has been detected and the luminosity flinction has been derived. Key words: uvby UBV photometry - galactic cluster - luminosity flinction - stellar evolution

New color-magnitude data for twelve globular clusters

This paper presents results of a major program of BV photoelectric and photographic photometry of southern globular clusters. The observational data for this program have been obtained primarily at Las Campanas, Chile, with additional material from Cerro Tololo. New color-magnitude diagrams are presented for 11 clusters (NGC 2808, 4590, 5694, 5824, 6325, 6517, 6681, 6715, 6809, 6864, and 7089); and for one additional cluster (NGC 6266) measurements of the variable stars are listed. For 10 of these objects, no C-M diagrams in the UBV system have previously been published. The features of the diagrams are discussed briefly and used to derive basic information about the clusters, such as their distances, reddenings, and characteristics of the giant and horizontal branches. More extensive discussions are presented for four particularly interesting clusters (NGC 2808, 5694, 6864, and 7089). The first of these (NGC 2808) shows a unique HB morphology, and the third (NGC 6864) is a moderately metal-rich object with an unusually large population of HB stars relative to the giant-branch stars. The second object, NGC 5694, has long been known as a possible ''intergalactic'' cluster that may be escaping from the Galaxy. The information discussed here indicates that NGC 5694 may bemore » gravitationally bound to the Galaxy if the galactic halo within approx.25 kpc is slightly more massive than in conventional models. Finally, NGC 7089 (M2) is shown to have characteristics that modify earlier conclusions from Arp's classical (m/subp// subg/, m/subp//subv/) photometry. (AIP)« less

UBV-photometry of flare stars in the Pleiades

At present about 450 flare stars are known in the Pleiades region, the majority of which belong to the cluster. Their coloz-magnitude diagram and (U -- B, B V) color-color diagram have great significance for the study of the nature of these stars, and also for the problems of evolution of the stars. The first systematic photographic investigations of the stars in the Pleiades were carried out by Binnendijk [6] and by Hertzsprung et al. [7]. Colors of a large number of stars have been determined in the UBV system by photographic and photoelectric methods by Johnson and Mitchell [8], Ahmed, Lawrence, and Reddish [9], and Iriarte [10-12]. However, only a few tens of known flare stars are contained in the papers indicated above. The present paper has been devoted to UBV photographic photometry of flare stars in the Pleiades.

Dynamics of early type galaxies. I - The rotation curve of the elliptical galaxy NGC 4697

The rotation curve, up to O'.6 from the center, has been derived from Ca ii H and K lines for the elliptical galaxy NGC 4697. A maximum seems to be reached at 15" with 65 km s '. The same galaxy has been investigated by means of photographic photometry in the B system. The luminosity profile follows the r114 law, and the mean ellipticity is 0.4. The total apparent magnitude is B = 10.30 mag, and the corresponding absolute magnitude reaches MB = - 20.5 mag, assuming a distance of 14.8 Mpc. The spatial velocity curve and the light density profile are derived. Mass and angular momentum have been computed on the hypothesis that the mass-to-light ratio is constant through the galaxy, leaving it as a free parameter. Under several assumptions it is found that the angular momentum of the elliptical NGC 4697 is lower than that of a spiral of comparable mass by a factor 5 to a factor 30, when the mass-to-light ratio varies from 5 to 50. Subject headings: galaxies, individual galaxies, motion in

Study of the inner satellites of Saturn by photographic photometry

Good photographs of Saturn and its five inner satellites were obtained on January 2, 1974 with the 105 cm telescope at Pic du Midi Observatory with exposure times of 45 sec. The spread function is constant over the field, and isotropic. The true photometric profiles of the satellites are obtained after deriving a model for the stray light coming from the rings. The magnitudes, computed by integration, are in good agreement with published values except for Mimas, which is nearly one magnitude fainter then previously believed.

The distribution of interstellar matter in NGC 654

The young cluster NGC 654 is studied using UBV photographic photometry with a view to determining the distribution of interstellar matter in a region where star formation recently occurred.

UBV PHOTOMETRY OF NGC 6649.

ABSTRACT This paper reports UBV photographic photometry of NGC 6649 and the analysis to derive a minimum distance modulus, (m - AI)o, of which indicates the cluster is well within the Carina-Sagittarius-Scutum arm of the Milky Way. Distance and age of the cepheid V367 Sct near the cluster center are consistent with cluster membership. Key words: galactic cluster - UBV photometry - cepheid variables

Astronomical supplement to the 1:5 000 000 albedo map of the moon and the establishment of a 1:2 500 000 auxiliary mosaic

view Abstract Citations (2) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Astronomical supplement to the 1:5000000 albedo map of the moon and the establishment of a 1:2500000 auxiliary mosaic. Wildey, R. L. Abstract A photoelectrically calibrated isodensity mosaic of the full Moon has been produced at a scale of 1:2 300 000. A control grid was produced for guiding the mosaicking of the isodensitracing as an ortho- graphic projection of the system of selenographic coordinates in the direction of the observing station ac- cording to the deduced topocentric libration of the epoch. The source of photometric error due to the spectral mismatch between photoelectric and photographic photometry is fully investigated and found to be negligible. This conclusion also applies to the U.S. Geological Survey 1:5 000000 albedo map. Since recent results indicate that correction to a true phase angle of zero is often too large to be a blanket correc- tlo over the whole lunar face and is also variable according to the geologic nature of the terrain, a graphi- cal device has been produced that allows one to read the true phase angle applicable at any selenographic coordinate for either the 1:5000000 albedo map or the 1:2500000 iso den sity mosaic. The new calibration has been rendered in terms of "infranormal" albedo, an observational lower bound to the true normal al- bedo, which can easily be normalized at the investigator's discretion. An alternative absolute calibration method was employed, which produced agreement with the previous scale provided an effective wavelength of 5390 A is assumed. Analysis of the dependence on data scatter of the least-square relationship between photoelectric albedo and photographic density shows that an accurate curve has been obtained. The present document provides all necessary information for using and assessing the reliability of the 1:2 500000 iso- density mosaic, which is in five colors, now housed at the U.S. Geological Survey, Flagstaff, Arizona. Publication: The Astronomical Journal Pub Date: December 1974 DOI: 10.1086/111703 Bibcode: 1974AJ.....79.1471W Keywords: Albedo; Astronomical Photometry; Lunar Maps; Lunar Photography; Ubv Spectra; Black Body Radiation; Electrophotometry; Light Curve; Luminance; Mosaics; Optical Density; Spectral Energy Distribution; Lunar and Planetary Exploration full text sources ADS |

Reducing the influence of the development upon the photographic photometry of continuous spectra and line spectra

Reducing the influence of the development upon the photographic photometry of continuous spectra and line spectra

FAINT OB STAR BEHIND THE COALSACK.

ABSTRACT An investigation of OB stars in the Coalsack region is done by means of UBV photographic photometry. The study includes previously known OB stars within a 1 radius circle centered at = 302? 4, b = -0? 2, and newly discovered faint OB stars in five small areas (80 square arc minutes each) within the same circle. Total visual absorption values and minimum distance moduli are derived for all the stars, and the absorption vs. distance modulus diagram is presented. A possible distant OB association is noted in the region sur rounding the compact cluster Hogg 15. Key words: interstellar matter - reddening - OB stars - spiral structure

A Martian yellow cloud—July 1971

A short-term yellow cloud was observed in the southern hemisphere of Mars from July 10 to 22, 1971. The initial cloud was first photographed on the morning limb at 7:45 am local Martian sun time in the Serpentis-Hellespontus region (315°W; 27°S), 74 Earth days (72 Martian days) prior to the onset of the September major yellow storm. Historical observations from the Lowell Observatory archives indicate that prestorm yellow clouds of limited extent are not uncommon. Positional measurement and photographic differential photometry of the July yellow cloud were possible throughout its entire evolution because Mars was favorably situated and photographic coverage by the International Planetary Patrol was adequate. Maps showing the cloud's initial location, hourly and diurnal behavior, apparent motion, and areal coverage by haze are presented. The similarities between the July cloud and other southern hemisphere yellow clouds are summarized. Its relationships to classical albedo features and Mariner 9 topographic data are discussed. Photographic photometry indicates that the enhanced contrast between the yellow cloud and its surroundings is probably due more to the brightening of the cloud-covered areas than to any darkening of contiguous areas.

UBV Photometry of Bright Stars and Variables in the Globular Cluster NGC 6723

Photographic photometry on the UBV system is presented for stars brighter than V = 17 m in NGC 6723. The height of the giant branch, |$\Delta V=2^\text m.3$| , and the colour of the subgiant branch, |$(B-V)_{0, \text g}=0.92$| , are consistent with a relatively high metal abundance in the cluster stars. This is supported by the value for the ultraviolet excess of the giants, |$\delta(U-B)=0.15$| , obtained from the two-colour diagram. From the position of the blue horizontal branch stars in the latter diagram, the reddening is found to be negligible. Ten new RR Lyrae stars and two red, possibly semi-regular, variables have been discovered in the cluster and one nearby H α emission star which is probably associated with the Corona Australis dark cloud was also found to be variable. BV photographic photometry is presented for these and for most of the already known variables in the cluster. Periods have been found for all the measurable RR Lyrae stars. The ratio by number of c-type to ab-type variables is 5/24 and the mean periods of the two groups are 0.291 days and 0.540 days, respectively, which are characteristic of an Oosterhoff type I cluster. The amplitude–period, amplitude–colour and period–colour diagrams for 12 RR Lyrae variables with the best photometry are consistent with a metal abundance in NGC 6723 between that of M3 and that of NGC 6171. The distribution of stars along the horizontal branch shows a marginal bias to the red side of the RR Lyrae gap and there appears to be a minimum in the number of stars as a function of ( B−V ) which coincides with the region occupied by the c-type RR Lyrae stars. This feature is also evident in the horizontal branches of two other relatively metal rich clusters, NGC 6712 and NGC 6981.

The Turn-off Point of Omega Centauri

Photoelectric and photographic photometry to below V = 19 in the globular cluster ω Cen indicate that the main sequence turn-off point occurs at about V = 18.3, nearly four magnitudes below the horizontal branch. ω Cen thus differs from most other clusters which have been studied, since this magnitude difference is usually near 3.4 mag. Some implications are discussed briefly.

Photographic photometry in the field of NGC 2264.

Photographic photometry in the field of NGC 2264.

Photographic Surface Photometry of the Nebulae Surrounding V380 Ori and R Mon

The results presented here are the first in an extensive programme of multi-colour photographic surface photometry of peculiar nebulosities surrounding young stars which is made possible by the use of the galaxy plate measuring machine. The method of producing brightness and colour maps which are calibrated by in-focus stellar images recorded by Galaxy's incremental scan facility is described. The present observations of the nebulosities surrounding V380 Ori and R Mon in U B V H/sub alpha / and I show that both nebulae are biuer than the stars and that NGC 2261 surrounding R Mon has a distinct colour pattern. (auth)

Photographic photometry of compact galaxies near the north galactic pole

AbstractPhotographic photometry in U, B, r, of 265 compact galaxies from a sample selected by RICHTER, RICHTER, and SCHNELLER (1972) is presented. The colours of most of them resemble the colour of E‐galaxies. A few objects show a blue or ultraviolet excess if compared with E‐galaxies. Some of these may be galaxies with an active nucleus (Seyfert or N‐Type).