- ID:
- ivo://CDS.VizieR/J/A+AS/146/365
- Title:
- O & B stars uvby-Hbeta photometry. III.
- Short Name:
- J/A+AS/146/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stroemgren and H{beta} photometry of O and B type stars, generally brighter than 9.5 mag is reported for the field of the Carina Spiral Feature. The observations are based on the PPM (Cat. <I/193>) catalogue identifications and are designed to improve the completeness of the existing uvby{beta} data for the bright early-type stars in the field. We present new uvby photometry for 283 stars and H{beta} photometry for 225 of them. These observations are part of an ongoing effort to study the structure of selected star-forming regions in the Milky Way by means of uvby{beta} photometry. A comparison of the new data to other uvby{beta} data sets for this field is presented.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/459/880
- Title:
- Open clusters in Auriga OB2
- Short Name:
- J/MNRAS/459/880
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the area around the HII region Sh 2-234, including the young open cluster Stock 8, to investigate the extent and definition of the association Aur OB2 and the possible role of triggering in massive cluster formation. We obtained Stromgren and J, H, Ks photometry for Stock 8 and Stromgren photometry for two other cluster candidates in the area, which we confirm as young open clusters and name Alicante 11 and Alicante 12. We took spectroscopy of ~33 early-type stars in the area, including the brightest cluster members. We calculate a common distance of 2.80+0.27-0.24kpc for the three open clusters and surrounding association. We derive an age 4-6Ma for Stock 8, and do not find a significantly different age for the other clusters or the association. The star LS V +34 23, with spectral type O8 II(f), is likely the main source of ionization of Sh 2-234. We observe an important population of pre-main-sequence stars, some of them with discs, associated with the B-type members lying on the main sequence. We interpret the region as an area of recent star formation with some residual and very localized ongoing star formation. We do not find evidence for sequential star formation on a large scale. The classical definition of Aur OB2 has to be reconsidered, because its two main open clusters, Stock 8 and NGC 1893, are not at the same distance. Stock 8 is probably located in the Perseus arm, but other nearby HII regions whose distances also place them in this arm show quite different distances and radial velocities and, therefore, are not connected.
- ID:
- ivo://CDS.VizieR/J/AJ/151/125
- Title:
- Optical and UV photometry of SN 2013dy
- Short Name:
- J/AJ/151/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extensive and independent observations of Type Ia supernova (SNIa) SN2013dy are presented, including a larger set of UBVRI photometry and optical spectra from a few days before the peak brightness to ~200days after explosion, and ultraviolet (UV) photometry spanning from t~-10days to t~+15days refers to the B band maximum. The peak brightness (i.e., M_B_=-19.65+/-0.40mag; L_max_=[1.95+/-0.55]*10^43^/ergs) and the mass of synthesized ^56^Ni (i.e., M(^56^Ni)=0.90+/-0.26M_{Sun}_) are calculated, and they conform to the expectation for an SNIa with a slow decline rate (i.e., {Delta}m_15_(B)=0.90+/-0.03mag). However, the near infrared (NIR) brightness of this SN (i.e., M_H_=-17.33+/-0.30mag) is at least 1.0mag fainter than usual. Besides, spectroscopy classification reveals that SN2013dy resides on the border of "core normal" and "shallow silicon" subclasses in the Branch et al. classification scheme, or on the border of the "normal velocity" SNeIa and 91T/99aa-like events in the Wang et al. system. These suggest that SN2013dy is a slow-declining SNIa located on the transitional region of nominal spectroscopic subclasses and might not be a typical normal sample of SNeIa.
- ID:
- ivo://CDS.VizieR/J/A+A/399/271
- Title:
- Oscillations in the PMS star V346 Ori
- Short Name:
- J/A+A/399/271
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of periodicities in the light curve of the Pre-Main Sequence (PMS) Herbig Ae star V346 Ori. We interpret variations in the light curve of the star as the superposition of at least two periodic signals that result from delta Scuti-type stellar oscillations. The computation of linear non-adiabatic radial pulsation models for PMS stars reproduces these periods for a 1.55M_{sun}_ star with Teff=7410K and log(L/L_{sun}_)=0.74 pulsating in the fundamental and in the second overtone. If our assumption of radial oscillations is indeed correct, the star's location on the HR diagram places it at a distance significantly smaller than that of the Orion star forming region, hence raising questions regarding the evolutionary status of V346 Ori. Observations with better time sampling and spanning a longer period of time are needed if the latter question is to be addressed fully.
- ID:
- ivo://CDS.VizieR/II/207A
- Title:
- Palomar-Green catalog UV-excess stellar objects
- Short Name:
- II/207A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Palomar-Green Catalogue of UV-excess stellar objects provides positions accurate to about 8arcsec in each coordinate, photographic B-magnitudes accurate to 0.29mag, spectral types, some cross-references, and photoelectric broad-band, multichannel, and Stroemgren colors when available. Of the 1874 objects in the catalogue as published in 1986 (1878 in this version), 1715 comprise a statistically complete sample covering 10714 square degrees from 266 fields taken on the Palomar 18-inch Schmidt telescope. Limiting magnitudes vary from field to field, ranging from 15.49 to 16.67. The overall completeness is estimated to be 84%, but that figure and the relative contributions of magnitude, color, and accidental errors vary depending on the magnitude and color distribution of the spectroscopic subsample.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A28
- Title:
- Period variation in BW Vulpeculae redux
- Short Name:
- J/A+A/544/A28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the past 25 years, BW Vulpeculae has been the topic of period analyses centered on a secular period change with a periodic variation superposed, presumed to be due to light time effects in a binary system. According to this paradigm, one would expect what seems like a period increase of about 0.5s during or soon after the year 2001. I have continued photometric monitoring through the year 2012, adding 40 new timings of maximum and minimum light. This expected change in period did not occur, which rules out that interpretation of the period variation. As of 2012, the observed timings are about two hours early compared to those predicted by the quadratic ephemeris, but are very close to those predicted by the linear ephemeris. In fact, the period has remained constant for the last 32 years, indicating that the previous epochs of constant period are almost certainly the correct interpretation, though the cause of the period changes is still not clear. Continued photometric monitoring of BW Vul leads to the conclusion that the period changes are abrupt, followed by epochs of constant period lasting between 12 and at least 32 years.
- ID:
- ivo://CDS.VizieR/V/92A
- Title:
- Photometric and Spectroscopic Databases for LSS Stars
- Short Name:
- V/92A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains databases of published photoelectric UBVbeta data, MK-system spectral classifications, and Stroemgren four-color uvby photometry for objects in the Stephenson-Sanduleak "Luminous Stars in the Southern Milky Way" catalog (LSS catalog). The catalog contains mostly OB stars and A and F supergiants. These databases have been compiled from the literature.
- ID:
- ivo://CDS.VizieR/J/A+AS/140/29
- Title:
- Photometric monitoring of 47 late-type stars
- Short Name:
- J/A+AS/140/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present continuous multicolor photometry for 47 stars from October 1996 through June 1997. Altogether, 7073 V(RI)_c_, UBV, and by data points, each the average of three individual readings, were acquired with three automatic photoelectric telescopes (APTs) at Fairborn Observatory in southern Arizona. Most of our targets are chromospherically active single and binary stars of spectral type G to K but there are also four pre-main-sequence objects and three pulsating stars in our sample. The light variability is generally due to rotational modulation of an asymmetrically spotted stellar surface and therefore precise rotational periods and their seasonal variations are determined from Fourier analysis. We also report on photometric variations of {gamma} CrB (A0V) with a period of 0.44534 days. All data are available in numerical form.
- ID:
- ivo://CDS.VizieR/V/125
- Title:
- Photometry and Spectroscopy for Luminous Stars
- Short Name:
- V/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- of the paper: The birthrate of stars of masses >=10M_{sun}_ is estimated from a sample of just over 400 O3-B2 dwarfs within 1.5kpc of the Sun and the result extrapolated to estimate the Galactic supernova rate contributed by such stars. The solar-neighborhood Galactic-plane massive star birthrate is estimated at ~176stars/kpc^3^/Myr. On the basis of a model in which the Galactic stellar density distribution comprises a "disk+central hole" like that of the dust infrared emission (as proposed by Drimmel and Spergel), the Galactic supernova rate is estimated at probably not less than ~1 nor more than ~2 per century and the number of O3-B2 dwarfs within the solar circle at ~200000.
- ID:
- ivo://CDS.VizieR/J/AJ/147/7
- Title:
- Photometry and spectroscopy of NGC 6520
- Short Name:
- J/AJ/147/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use CCD and photoelectric photometry with Stromgren filters along with medium resolution spectra to investigate NGC 6520, an open cluster very nearly in the direction of the galactic center. We find an age of 60Myr, a distance of 2kpc, and an average reddening E(b-y)=0.295, which increases toward the south. The average heliocentric radial velocity of the B stars is -29km/s, while the velocity of the nearby Barnard 86 is about 0 (heliocentric; -11km/s compared to the LSR). This velocity difference amounts to about 1.8kpc since the cluster formed, implying that it is extremely doubtful NGC6520 is related to Barnard 86.
