Оглавление
Изображения
Загрузить ваше изображение
DSS Images Other Images
Публикации по объекту
Coordinates and Identifications of Harvard Variables
Coordinates and identifications are presented for 726 Harvard Variablestars and suspected variables, discovered or studied by D. Hoffleit andannounced in Harvard Bulletins 874, 884, 887, 901, and 902; plus 141others, previously known, lying in the same fields.
| The overlapping open clusters NGC 1750 and NGC 1758. III. Cluster-field segregation and clusters physical parameters
Cluster-field segregation and determination of physical parameters ofthe open clusters NGC 1750 and NGC 1758 were performed from CCD andphotographic photometric and astrometric surveys previously published bythe authors. Membership probabilities were computed to a brightnesslimit of R=15 mag through a non-standard method in a fullynon-parametric approach, using proper motions, positions and photometry.This study allowed several parameters for NGC 1750 and NGC 1758 to bedetermined, including position, size, density profile, absorption,distance, age, luminosity function and mass. The common colour excess ofboth clusters is E(B-V)=0.34 mag. NGC 1750 is slightly younger (log t =8.3), closer (V-M_v=9.0 mag) and less concentrated than NGC 1758 (log t= 8.60 and V-M_v=9.4 mag). We also conclude that NGC 1746 is anerroneous assignation (not corresponding to any real open cluster), andthat NGC 1750 and NGC 1758 are overlapping clusters, but they do notconstitute a gravitationally bounded system.
| The overlapping open clusters NGC 1750 and NGC 1758. II. $\vec BVR photographic photometry and proper motions
Astrometry (positions and proper motions) and photographic BVRphotometry were determined from a set of 29 photographic plates and CCDdata in a region of 2.3(deg}x2.3({deg)) in the area of open clusters NGC1750 and NGC 1758 in Taurus. The iterative central overlap algorithm wasused for the proper motion calculations. Plate-to-plate transformationsand astrometric magnitude effects are discussed in detail. CCD datainteract with photographic material in three different ways: for theelimination of astrometric magnitude effects, for the photometricstandard calibration of photographic plates and for building a CCDpseudo-plate used for astrometric purposes as any other photographicplate. A preliminary analysis of the resulting photometric andastrometric catalogue confirmed the reality of two different clusters inthe zone (NGC 1750 and NGC 1758). There were no indications for theexistence of NGC 1746. Tables 6 and 11 are only available in electronicform from CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/Abstract.html
| Determination of proper motions and membership of the open clusters NGC 1750 and NGC 1758
The kinematic state of the open clusters NGC 1750 and NGC 1758 has beenstudied using newly determined proper motions for 540 stars in a fieldof 1.5 deg x 1.5 deg in the Taurus dark cloud region. The proper motionsare obtained from the reduction of PDS measurements of 20 plates thatspan a total time interval of 68 years, resulting in an average propermotion accuracy of 0.67 mas/yr. These proper motions are used todetermine the membership probabilities of stars in the region by meansof a new, improved method described in this paper. Of the 540 starsanalyzed here, 332 are found to be probable members of NGC 1750, and 23are probable members of NGC 1758. The core radii of NGC 1750 and NGC1758 are determined to be 17'2 and 2'25 respectively.
| The overlapping open clusters NGC 1750 and NGC 1758. I. UBVRI-CCD photometry
The existence and relationship of the possible clusters NGC 1746, NGC1750 and NGC 1758 has been a matter of discussion during the lastdecades. This star field is close to the galactic anticenter and lies inthe direction of the Taurus dark cloud complex. As part of acomprehensive astrometric and photometric analysis of this zone, wepresent a brief historical introduction together with deep UBVRI-CCDphotometry of the area. The presence of at least one cluster can bededuced from these data. This object has a position and apparent sizecompatible with those previously quoted for NGC 1750 and NGC 1758. It isnot possible to distinguish the single or double nature of the clusteron the sole basis of our photometry and the spatial distribution of thestars. No photometric evidence was found for NGC 1746. Based onobservations made at the Centro Astronómico Hispano-Alemánand the Observatorio Astronómico Nacional in Calar Alto, Almeria,Spain. Table 5 is only available in electronic form from CDS viaanonymous ftp 130.79.128.5, and by e-mail request todgaladi@pchpc5.am.ub.es
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| Stars classified as constant in the General Catalog of Variable Stars
Photometric observations have been made of 16 stars classified asconstant, CST, or CST; in the General Catalog of Variable Stars. Onestar, U Tauri, was found to be a rapid irregular variable and threeothers may vary at a low level. In two cases, FV Delphini and FPGeminorum, the star identified as the variable on published findingcharts is not variable but a nearby star did vary. It is suggested thatthe wrong stars were marked on the charts but the possibility remainsthat the variables may have exhibited constancy during earlierobservations.
| Probable open clusters NGC 1750 and NGC 1758 behind the Taurus dark clouds
The area of 2.5 x 2.5 deg in the direction of the Taurus dark cloudscontaining stellar groupings NGC 1746, NGC 1750, and NGC 1758 isinvestigated in the Vilnius photometric system. Magnitudes V, colorindices, color excesses, interstellar extinctions, and distances aredetermined for 116 stars, some of which are as faint as V = 13. It isconcluded that NGC 1746 is probably not a cluster. Other two groupingsof stars, NGC 1750 and NGC 1758, if real, may be open clusters at 510and 680 pc distances. Interstellar reddenings E(B-V) of both groups are0.42 and 0.37 mag, respectively. The distance of the Taurus dark cloudsin the area is found to be 175 pc, i.e. by 45 pc larger than in otherdirections farther to the south from the galactic equator.
| Cracow Observations of Variable Stars
Not Available
| Infrared Observations of Southern RV Tauri Stars
Abstract image available at:http://adsabs.harvard.edu/abs/1972PASP...84..768G
| The periods of long-period variable stars and their dependence on the galactic position
Not Available
| Photoelectric light curves of FG Hya.
Abstract image available at:http://adsabs.harvard.edu/abs/1963AJ.....68...30B
| Le type de population des céphéides galactiques; critères de distinction des types et catalogue
Not Available
| Red indices in galactic clusters
Not Available
|
Добавить новую статью
Внешние ссылки
- - Внешних ссылок не найдено -
Добавить внешнюю ссылку
Группы:
|
Наблюдательные данные и астрометрия
| Созвездие: | Телец |
| Прямое восхождение: | 05h04m13.97s |
| Склонение: | +23°38'50.9" |
| Видимая звёздная величина: | 9.983 |
| Собственное движение RA: | -1.4 |
| Собственное движение Dec: | -3 |
| B-T magnitude: | 10.2 |
| V-T magnitude: | 10.001 |
Каталоги и обозначения:
|
