Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/127/1632
- Title:
- UBVR(UIT) photometry of O and OB stars in SMC
- Short Name:
- J/AJ/127/1632
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distribution of N*, the number of OB stars per association or cluster, appears to follow a universal power-law form (N*)^-2^ in the local universe. We evaluate the distribution of N* in the Small Magellanic Cloud using recent broadband optical and space-ultraviolet data, with special attention to the lowest values of N*. We find that the power-law distribution in N* continues smoothly down to N*=1. This strongly suggests that the formation of field massive stars is a continuous process with those in associations and that the field stars do not originate from a different star formation mode.
1873. UBV sequences in Cen
- ID:
- ivo://CDS.VizieR/J/A+A/14/164
- Title:
- UBV sequences in Cen
- Short Name:
- J/A+A/14/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric UBV observations were made with the ESO 1m telescope and the ESO photometer on 6 nights between 1970-04-01 and 1970-05-03. The observations were centered around (B1950)13:24-62:23 The positions and identifications of the 3 sequences were computed by B. Skiff (Lowell Obs.) in September 2010, from a comparison of the published charts with the computer screen-plots of UCAC2.
- ID:
- ivo://CDS.VizieR/J/AJ/75/167
- Title:
- UBV sequences near 3 globulars
- Short Name:
- J/AJ/75/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results concerning photoelectrically observed UBV magnitudes and colors of bright to intermediately faint stars near three globular clusters (NGC 2808, 5927, and 6101) are assembled.
- ID:
- ivo://CDS.VizieR/J/A+AS/125/11
- Title:
- UBV & V(RI)c photometry of 23 active stars
- Short Name:
- J/A+AS/125/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the progress of our ongoing photometric monitoring program of spotted late-type stars with automatic photoelectric telescopes (APTs) on Mt. Hopkins in Arizona and on Mt. Etna in Sicily. We present 9250 differential UBV and/or V(RI)c observations for altogether 23 chromospherically active stars, singles and binaries, pre-main-sequence and post-main-sequence, taken between 1991 and 1996. For a description of the UBV and (RI)c photometric system, see e.g. <GCPD/01> and <GCPD/54>
- ID:
- ivo://CDS.VizieR/J/A+A/364/205
- Title:
- UBVy photometry of cool stars
- Short Name:
- J/A+A/364/205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision photometry, high- and medium-resolution spectroscopy for a sample of 32 stars likely to be the optical counterparts of X-ray sources serendipitously detected by the EXOSAT satellite. Using also recent results from the Hipparcos satellite, we infer spectral types, compute X-ray luminosities and Li abundances and investigate the single or binary nature of the sample stars. We found eleven new variable stars, whose photometric periods fall in the 1.2-27.5 day range, for most of which the optical variability is consistent with the presence of photospheric cool spots. For our sample of X-ray selected stars we confirm the existence of a strong correlation between the stellar rotation rate and the level of activity, and also between the X-ray and bolometric luminosities. Two stars in our sample are likely to be pre-main sequence objects, one is likely to be a previously unknown M-type star within 25pc.
1877. UCAC4 nearby star survey
- ID:
- ivo://CDS.VizieR/J/AJ/148/119
- Title:
- UCAC4 nearby star survey
- Short Name:
- J/AJ/148/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use data from the U.S. Naval Observatory fourth CCD Astrograph Catalog (UCAC4) in combination with photometry from the AAVSO Photometric All-Sky Survey and Two Micron All-Sky Survey to identify stars within 25pc of the Sun. A sample of nearby stars with accurate trigonometric parallaxes from the Research Consortium On Nearby Stars is used to generate a set of 16 new photometric color-M_K_ relations that provide distance estimates with uncertainties of 15%. This work expands the available suites of well-calibrated photometric distance relations that can be used to identify nearby stellar systems. The distance relations are used with quality cuts to extract an initial sample of stars from the UCAC4 estimated to be within 25pc. Color, proper motion, and existing literature sources are then used to obtain a clean sample of red dwarfs, while limiting the amount of contamination from background giants, resulting in a sample of 1761 candidate nearby stars within 25pc. Of these, 339 are new discoveries with no previously known published parallax or distance estimate, primarily with proper motions less than 0.2arcsec/yr. Five stars are estimated to be within 10pc, with the nearest, TYC 3980 1081 1, with V=10.50 estimated to be at 5.9pc. That several hundred new stars have been revealed so close to the Sun illustrates once again that there is considerable work yet to be done to map the solar neighborhood and that additional nearby stars are likely still to be discovered.
- ID:
- ivo://CDS.VizieR/J/ApJS/123/377
- Title:
- u*g*r*i*z* Photometry of stars, galaxies, QSOs
- Short Name:
- J/ApJS/123/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog (table 5 of the paper) contains the measurements of 2262 sources, including 334 extended sources, 1915 point sources, and 13 known QSOs, in five passbands close to the u'g'r'i'z' passbands of SDSS (see the definition of the photometric system in Richards et al., 1997PASP..109...39R). Of these objects, over 1600 are measured in 15 fields covering 0.5deg^2^, with a limiting magnitude of r*<19.5, similar to the photometric limit of the SDSS spectroscopic survey.
- ID:
- ivo://CDS.VizieR/J/A+AS/145/399
- Title:
- UKS 2 open cluster BV photometry
- Short Name:
- J/A+AS/145/399
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Colour-magnitude diagrams are presented for the first time, of the faint southern star cluster UKS 2, which was for a long time reported as a globular cluster candidate. The V vs. B-V diagrams indicate that UKS 2 is an open cluster with age comparable to that of the Hyades. It has a reddening of E(B-V)=0.40 and is located at a distance from the Sun of d_{sun}_=~7kpc. The cluster is located outside the solar radius at galactocentric distance projected on the plane r_GC_=~11kpc, and a height z=~-370pc.
- ID:
- ivo://CDS.VizieR/J/AJ/141/163
- Title:
- Ultimate light curve of SN 1998bw/GRB 980425
- Short Name:
- J/AJ/141/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multicolor light curves of SN 1998bw which appeared in ESO184-G82 in close temporal and spatial association with GRB 980425. The light curves are based on observations conducted at Cerro Tololo Inter-American Observatory (CTIO) and data from the literature. The CTIO photometry reaches ~86-days after the gamma-ray burst (GRB) in U and ~160-days after the GRB in BV(RI)C. The observations in U extend the previously known coverage by about 30-days and determine the slope of the early exponential tail. We calibrate a large set of local standards in common with those of previous studies and use them to transform published observations of the supernova (SN) to our realization of the standard photometric system.
