- ID:
- ivo://CDS.VizieR/J/A+A/532/A78
- Title:
- Long-period variables in NGC 147 and NGC 185
- Short Name:
- J/A+A/532/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies on the stellar content of the two nearby dwarf galaxies NGC 147 and NGC 185 reveal a rich population of late-type giants in both systems, including a large number of carbon-rich objects. These stars are known to show pronounced photometric variability, which can be used for a more detailed characterisation of these highly evolved stars. Owing to their well-studied parameters, these Local Group members are ideal candidates for comparative studies. Through photometric monitoring, we attempt to provide a catalogue of long-period variables (LPVs), including Mira variables, semi-regular variables, and even irregular variables in NGC 147 and NGC 185. We investigate the light variations and compare the characteristics of these two LPV populations with the results found for other galaxies, such as the LMC.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/585/A111
- Title:
- Long period variables in omega Cen
- Short Name:
- J/A+A/585/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies have detected multiple populations in globular clusters. The massive globular cluster {omega} Cen hosts at least three populations of different metallicity. The most metal-rich one is thought to show also an overabundance of He. These differences should become visible in the structure, evolution, and pulsation of its stars. We aim to study the effects of the different starting compositions of the three populations in {omega} Cen on the most luminous red giants in this cluster. The long-periodic variability of evolved stars in {omega} Cen opens a comparably easy access window to the structure and composition of these objects. We made a detailed search for long-period variables (LPVs) in {omega} Cen leading to the detection of many new variables and period determinations for a significant number of them. Periods and luminosities were then compared with the most recent pulsation models for these kinds of stars.
- ID:
- ivo://CDS.VizieR/J/other/RAA/18.137
- Title:
- Long-term BVRI photometry of 15 PMS stars
- Short Name:
- J/other/RAA/18.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports results from the multicolor photometric observations of 15 pre-main sequence stars collected in the period September 2010 - October 2017. The stars from our study are located in the star-forming HII region IC 5070. These objects were previously detected as either emission line stars, flare stars, T Tauri variables or Herbig Ae/Be stars. Photometric observations, especially concerning the long-term behavior of the objects, are missing in the literature. We present the first photometric monitoring for all stars from our study. The analysis of the obtained BVRI photometric data allows us to draw the conclusion that all investigated objects are variable stars. In the case of LkHa 146, we identified previously unknown periodicity in its photometric variability.
- ID:
- ivo://CDS.VizieR/J/other/PASA/35.7
- Title:
- Long-term BVRI photometry of V2492 Cygni
- Short Name:
- J/other/PASA/35.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results from BVRI photometric observations of the young stellar object V2492 Cyg collected during the period from August 2010 to December 2017 are presented. The star is located in the field of the Pelican Nebula and it was discovered in 2010 due to its remarkable increase in the brightness by more than 5mag in R-band. According to the first hypothesis of the variability, V2492 Cyg is an FUor candidate. During subsequent observations, it was reported that the star shows the characteristics inherent to EXor- and UXor-type variables. The optical data show that during the whole time of observations the star exhibits multiple large amplitude increases and drops in the brightness. In the beginning of 2017, we registered a significant increase in the optical brightness of V2492 Cyg, which seriously exceeds the maximal magnitudes registered after 2010.
- ID:
- ivo://CDS.VizieR/J/other/BAJ/29.10
- Title:
- Long-term BVRI photometry of V1704 Cygni
- Short Name:
- J/other/BAJ/29.1
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Results from BVRI photometric observations of the pre-main sequence star V1704 Cyg collected during the time period from August 2010 to December 2017 are presented. The star is located in the star-forming HII region IC 5070 and it exhibits photometric variability in all optical passbands. After analysing the obtained data, V1704 Cyg is classified as a classical T Tauri star.
- ID:
- ivo://CDS.VizieR/J/other/Ser/202.31
- Title:
- Long-term BVRI photometry of V900 Mon
- Short Name:
- J/other/Ser/202.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from photometric monitoring of V900 Mon, one of the newly discovered and still under-studied object from the FU Orionis type. The FUor phenomenon is very rarely observed, but it is essential for stellar evolution. Since we only know about twenty stars of this type, the study of each new object is very important for our knowledge. Our data were obtained in optical spectral region with the BVRI Johnson-Cousins set of filters during the period from September 2011 to April 2021. In order to follow the photometric history of the object, we measured its stellar magnitudes on available plates from the Mikulski Archive for Space Telescopes. The collected archival data suggest that the rise in brightness of V900 Mon began after January 1989 and the outburst goes on so far. In November 2009, when the outburst was registered, the star had already reached the level of brightness close to the current one. Our observations indicate that during the period 2011-2017 the stellar magnitude increased gradually in each pass band. The observed amplitude of the ourburst is about 4 magnitudes (R). During the last three years, the increase in brightness has stopped and there has even been a slight decline. The comparison of light curves of the known FUor objects shows that they are very diverse and are rarely repeated. However, the photometric data we have so far show that V900 Mon's light curve is somewhat similar to those of V1515 Cyg and V733 Cep.
- ID:
- ivo://CDS.VizieR/J/AZh/88/34
- Title:
- Long-term (1984-2008) JHKLM photometry of stars
- Short Name:
- J/AZh/88/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Long-term (1984-2008) JHKLM photometry for 254 objects is presented. The observations were carried out in the standard JHKLM photometric system using an original method and a modern IR photometer designed and built at the Sternberg Astronomical Institute. Our program of studies included searches for and studies of relatively hot circumstellar dust envelopes.
- ID:
- ivo://CDS.VizieR/J/A+AS/131/321
- Title:
- Long-term monitoring of active stars. VIII.
- Short Name:
- J/A+AS/131/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a part of an extensive program focusing on the global properties and evolution of active stars, high-precision UBV(RI)c photometry of 31 selected stars, collected at the European Southern Observatory over the 14-29 February 1992 interval, is presented. Significant evolution of the light curves, period variations and evidence for long-term variability of the global degree of spottedness are found. Some spectral classifications are revised and the inferred photometric parallaxes are compared, whenever possible, with the values measured by the Hipparcos satellite. Flare events were detected for the star HD 16157=CC Eri, EXO 055609-3804.4=TY Col and HD 119285=V851 Cen. Optical variability was discovered for the Pop II binary HD 89499. These observations contribute to the establishment of a time-extended photometric database which can give important clues on topics such as the stability of spotted areas, differential rotation, solar-like cycles and the correlation between inhomogeneities at different atmospheric levels.
- ID:
- ivo://CDS.VizieR/J/A+A/499/967
- Title:
- Long-term monitoring of {gamma} Dor stars
- Short Name:
- J/A+A/499/967
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- gamma Dor stars are excellent targets for asteroseismology since the gravity modes present in these stars probe the deep stellar interiors. Mode identification will improve the knowledge of these stars considerably. A selected group of gamma Dor stars and some candidates were observed with the Mercator telescope to find and/or confirm the periodicities in the light variations and to derive reliable amplitude ratios in different pass bands. A frequency analysis was performed on all new data obtained in the Geneva photometric system. In order to have more reliable and accurate frequencies, the new data were combined with similar data from the literature and with Hipparcos observations. A set of frequencies that minimized the residuals in a harmonic fit was searched for while allowing means and amplitudes to vary from one observation set to another.
- ID:
- ivo://CDS.VizieR/J/other/PASA/32.21
- Title:
- Long-Term Multicolour Photometry of YSOs
- Short Name:
- J/other/PASA/32.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results from long-term multicolour optical photometric observations of the pre-main sequence stars FHO 26, FHO 27, FHO 28, FHO 29, and V1929 Cyg collected during the period from 1997 June to 2014 December are presented. The objects are located in the dense molecular cloud L935, named 'Gulf of Mexico', in the field between the North America and Pelican nebulae. All stars from our study exhibit strong photometric variability in all optical passbands. Using our BVRI observations and data published by other authors, we tried to define the reasons for the observed brightness variations. The presented paper is a part of our long-term photometric study of the young stellar objects in the region of 'Gulf of Mexico'.
