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Start Over Subject infrared photometry Subject variable stars Subject pre-main sequence stars
1. BVRI observations of the FUor star V582 Aur
ID:
ivo://CDS.VizieR/J/A+A/556/A60
Title:
BVRI observations of the FUor star V582 Aur
Short Name:
J/A+A/556/A60
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from optical photometric and spectroscopic observations of the eruptive pre-main sequence star V582 Aur. Variability of the star was reported a few years ago when it was suspected as a possible FU Orionis object. Due to the small number of currently known FUors, a new object of this type is ideal target for follow-up photometric and spectroscopic observations. We carried out BVRI CCD photometric observations in the field of V582 Aur from 2009 August to 2013 April. We acquired high-, medium-, and low-resolution spectroscopy of V582 Aur during this period. To study the pre-outburst variability of the target and construct its historical light curve, we searched for archival observations in photographic plate collections. The pre-outburst photographic observations of V582 Aur show low-amplitude light variations typical of T Tauri stars. Archival photographic observations indicate that the increase in brightness began in late 1984 or early 1985 and the star reached the maximum level of brightness at 1986 January. Our BVRI photometric observations show large amplitude variations ({Delta}V~2.8mag.) during the 3.5 year period of observations. Most of the time, however, the star remains in a state close to the maximum brightness. The deepest drop in brightness was observed in the spring of 2012, when the brightness of the star fell to a level close to the pre-outburst. The multicolor photometric data show a color reversal during the minimum in brightness, which is typical of UX Ori variables.
2. BVRI Photometry of 14 PMS stars
ID:
ivo://CDS.VizieR/J/other/BAJ/24.62
Title:
BVRI Photometry of 14 PMS stars
Short Name:
J/other/BAJ/24.6
Date:
21 Oct 2021
Publisher:
CDS
Description:
New photometric data from CCD multicolour BVRI observations of 14 pre-main sequence stars during the period from 2013 April to 2015 September are presented. The studied objects are located in the field of 'Gulf of Mexico' in the NGC 7000/IC 5070 star-forming complex. The stars from our study exhibit different types of photometric variability in all optical passbands. Using our long-term observations and data published by other authors, we tried to define the reasons for the observed brightness variations. On the basis of our new data previously unknown periodicity in the light curve of the star LkHa 189 (2.45-days) was registered.
3. BVRI photometry of 5 PMS stars
ID:
ivo://CDS.VizieR/J/other/BAJ/22.3
Title:
BVRI photometry of 5 PMS stars
Short Name:
J/other/BAJ/22.3
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new data from BVRI photometric observations of five PMS stars during the period from April 2013 to July 2014. The stars are located in the field of NGC 7000/IC 5070 ("Gulf of Mexico") - a region with active star formation. The presented paper is a continuation of our long-term photometric investigations of the young stellar objects in this region. The long-term multicolor photometric observations of PMS stars are very important for their exact classification. Our results show that the studied stars exhibit different types of photometric variability in all bands. We tried to classify them using our data from the long-term photometry and data published by other authors.
4. CCD photometry of YY Orionis stars
ID:
ivo://CDS.VizieR/J/A+AS/129/337
Title:
CCD photometry of YY Orionis stars
Short Name:
J/A+AS/129/337
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of photometric monitoring in the UBVRI bands of 5 YY Orionis stars and 2 other variable stars are presented. Each source was observed in the period of 1996, Nov. 23 to Dec. 2 and of 1996, Dec. 23 to 1997,Jan. 2 at the 1-m telescope of Wise Observatory, Israel. Tables.dat contain the luminosity variation of each star as deviation from its average observed magnitude.
5. Cygnus OB2 association NIR light curves
ID:
ivo://CDS.VizieR/J/A+A/640/A128
Title:
Cygnus OB2 association NIR light curves
Short Name:
J/A+A/640/A128
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a J, H, and K photometric variability survey of the central 0.78 square degrees of the young OB association Cygnus OB2. We used data observed with the Wide-Field CAMera at the United Kingdom Infrared Telescope in 2007 (spanning 217 days) to investigate the light curves of 5083 low mass candidate members in the association and explore the occurrence and main characteristics of their near-infrared variability. We identified 2529 stars (~50% of the sample) with significant variability with time-scales ranging from days to months. We classified the variable stars into the following three groups according to their light curve morphology: periodic variability (1697 stars), occultation variability (124 stars), and other types of variability (726 stars). We verified that the disk-bearing stars in our sample are significantly more variable in the near-infrared than diskless stars, with a steep increase in the disk-fraction among stars with higher variability amplitude. We investigated the trajectories described by variable stars in the color-space and measured slopes for 335 stars describing linear trajectories. Based on the trajectories in the color-space, we inferred that the sample analyzed is composed of a mix of young stars presenting variability due to hot and cold spots, extinction by circumstellar material, and changes in the disk emission in the near-infrared. We contemplated using the use of near- infrared variability to identify disk-bearing stars and verified that 53.4% of the known disk-bearing stars in our sample could have been identified as such based solely on their variability. We present 18 newly identified disk- bearing stars and 14 eclipsing binary candidates among CygOB2 lower-mass members.
6. JHK photometry near the Trapezium region
ID:
ivo://CDS.VizieR/J/AJ/121/3160
Title:
JHK photometry near the Trapezium region
Short Name:
J/AJ/121/3160
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of J, H, and Ks time-series photometry obtained with the southern 2MASS telescope over a 0.84{deg}x6{deg} region centered near the Trapezium region of the Orion Nebula cluster. These data are used to establish the near-infrared variability properties of premain-sequence stars in Orion on timescales of ~1-36days, ~2 months, and ~2 years. A total of 1235 near-infrared variable stars are identified, ~93% of which are likely associated with the Orion A molecular cloud.
7. JHKs photometry of Cha I variables
ID:
ivo://CDS.VizieR/J/AJ/124/1001
Title:
JHKs photometry of Cha I variables
Short Name:
J/AJ/124/1001
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a J, H, and Ks photometric monitoring campaign of a 0.72{deg}x6{deg} area centered on the Chamaeleon I star-forming region. Data were obtained on 15 separate nights over a 4 month time interval, from January to May 2000, using the Two Micron All Sky Survey south telescope. Out of a total of 34,539 sources brighter than the photometric completeness limits (J=16.0, H=15.2, and Ks=14.8), 95 exhibit near-infrared variability in one or more bands. The variables can be grouped into a population of bright, red objects that are associated with the Chamaeleon I association and a population of faint, blue variables that are dispersed over the full 6{deg} of the survey and are likely field stars or older pre-main-sequence stars unrelated to the present-day Chamaeleon I molecular cloud. Ten new candidate members of Chamaeleon I, including eight brown dwarf candidates, have been identified based on variability and/or near-infrared-excess emission in the J-H versus H-Ks color-color diagram. We also provide a compendium of astrometry and J, H, and Ks photometry for previously identified members and candidate members of Chamaeleon I.
8. Long-term BVRI photometry of 15 PMS 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.
9. Long-term BVRI photometry of V1704 Cygni
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.
10. Long-term BVRI photometry of V2492 Cygni
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.

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