uvby-beta Photometry for Bright O-G0 Southern Stars
Short Name:
II/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalog includes for each star as described in the title, the CDS number, HR number, V magnitude, (b-y) color index, m1, c1, beta, mean errors, sum of remarks. The rms errors of one observation are 0.013 mag, 0.005 mag, 0.006 mag and 0.008 mag for V, (b-y), m1 and c1, respectively.
In recent years a significant development has become evident in the study of the stellar structure of the Galactic disk. This is especially true for the 3rd Galactic quadrant, where the stellar population was extensively investigated beyond 10kpc, revealing details about the warped geometry of the thin and thick disks and outer arm. The 4th Galactic quadrant offers even better opportunity to follow the distribution of the young stellar populace to a large distance, since the line of sight is parallel to the largest single segment of a spiral arm seen from our position in the Galaxy: the Carina spiral feature. This paper further contributes to the study of the structure of the Galactic disk in the direction of Carina field utilizing homogeneous photometric distances of a sample of about 600 bright early-type stars seen in this direction up to 6kpc. The derived stellar distances are based on uvby{beta} photometry. All O and B type stars with uvby{beta} data presently available are included in the study.
Stroemgren uvby{beta} photometry has been collected for a total of 1017 stars earlier than G0 lying in an area of the sky containing the Southern Coalsack, the Musca, and the Chamaeleon dark clouds. The targets were selected from the SAO star catalog, and the results give V, b-y, m_1_, c_1_, and {beta} on the standard systems, with overall rms errors for one observation of one star of 0.008mag , 0.004mag , 0.006mag , 0.009mag , and 0.011mag , respectively.
We present the uvby{beta} data used to locate the dust and derive distances for nearby diffuse interstellar clouds in the EUV shadows lb27-31, lb165-32 and lb329+46 discovered by the Extreme Ultraviolet Explorer. The photometrically derived parallaxes of our program stars are compared to the parallaxes listed in the Hipparcos Catalog. Within the photometric distance limit of 150pc, the photometric parallaxes of 21 ``normal" stars are consistent with the Hipparcos measurements within an uncertainty of 15%. Much as expected for the Stroemgren system. Since all program stars are brighter than V=~11.5 most of them are included in the Tycho photometry. For our sample of ~200 stars we find V_by_ and V_T_ to be consistent. Few stars are common to published uvby{beta} catalogs, ~10, V and the indices compare well apart from {beta} where a zero point difference of 11mmag is noticed.
This investigation presents a study of the Galactic structure toward the Norma section of the Milky Way. The field studied is located between 325{deg} and 335{deg} Galactic longitude and -8{deg} to 8{deg} Galactic latitude. New observations in the uvby{beta} system are combined with all uvby{beta} data currently available to collate a sample of 130 O and B stars. A uniform procedure is applied to obtain the color excesses and stellar distances for all of the stars in the sample. The sample is magnitude limited to about V=9.5mag and contains the brightest stars of the open clusters NGC 6087 and Ly 6, the field 2158 of Loden, the OB association Nor OB1, and stars located in the directions of R 103 and R 105.
Results are presented of Stromgren uvby(beta) photometry for 213 stars earlier than G0 and brigher than mpg of about 10.7mag in Selected Area 203. The observed area lies close to the geometric center of the Chamaeleon-Musca dark clouds complex. The results yield V, (b-y), m1, c1, and beta on the standard systems, with overall rms errors for one observation of one star of 0.010, 0.004, 0.007, 0.009, and 0.011, respectively.
Photometric color excesses and distances plus heliocentric coordinates are calculated for 3762 southern A and early-F stars. The present results, combined with those previously published for the Northern Hemisphere, complete the coverage of the spatial distribution of interstellar reddening in the entire solar neighborhood. The new reddening maps show that the interstellar matter within 300pc of the Sun forms a single very large cloud complex that is somewhat asymmetrical with respect to both the galactic center and the galactic plane. This complex is characterized by pronounced local irregularities in both density and spatial extent. The observations further indicate that (1) the cloud complex is not associated with Gould's belt; (2) there exist large regions of the sky devoid of dust; (3) interstellar reddening is negligible at the galactic poles; (4) the role of intercloud dust in the Southern Hemisphere is minor although more important than in the Northern Hemisphere; (5) the Sun is not located in a dust-free, spherically symmetric bubble as previously thought; and (6) the Sun is, however, located in an elongated dust-free region known as the "local trough."
We present Stroemgren uvby and H_{beta}_ photometry for a set of 575 northern main sequence A type stars, most of them belonging to the Hipparcos Input Catalogue, with V from 5mag to 10mag and with known radial velocities. These observations enlarge the catalogue we began to compile some years ago to more than 1500 stars. Our catalogue includes kinematic and astrophysical data for each star. Our future goal is to perform an accurate analysis of the kinematical behaviour of these stars in the solar neighbourhood.
