Deep census of variable stars in a VLT/VIMOS field in Carina

Pietrukowicz, P.; Minniti, D.; Fernández, J. M.; Pietrzyński, G.; Ruíz, M. T.; Gieren, W.; Díaz, R. F.; Zoccali, M.; Hempel, M.

doi:10.1051/0004-6361/200912142

Cited by 7 publications

(15 citation statements)

References 31 publications

(42 reference statements)

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“…The simple search method we applied to our short-period data, the eye inspection of all light curves, turned out to be very effective. It is interesting that we have obtained almost the same rate of eclipsing/ellipsoidal systems as in our previous search in a VIMOS field in Carina (Pietrukowicz et al 2009). The binary detection rate would be very probably higher if the observations lasted considerably longer than only two days.…”

Section: Discussionsupporting

confidence: 81%

“…We used the DOPHOT package (Schechter et al 1993) Fernández et al (2006), Díaz et al (2007), Hoyer et al (2007), Minniti et al (2007), Pietrukowicz et al (2009) and Pietrukowicz et al (2010).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…In Table 2 we provide a census of the different types of variables found in field F170. It is worth to compare this table with Table 2 in Pietrukowicz et al (2009), which was prepared for the field F113, located at similar galactic latitude but ∼16 • farther away from the Galactic centre. The lower percentage of detected variables, 0.393% vs. 0.692%, can be explained by the shorter time coverage of the observations (two nights vs. four nights).…”

Section: The Variablesmentioning

confidence: 99%

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Variability and stellar populations with deep optical-IR images of the Milky Way disc: matching VVV with VLT/VIMOS data

Pietrukowicz

Minniti

Alonso-García

et al. 2012

A&A

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Aims. We have used deep V-band and JHK s -band observations to investigate variability and stellar populations near the Galactic plane in Centaurus, and compared the observations with the Galactic model of Besançon. Methods. By applying image subtraction technique to a series of over 580 V-band frames taken with the ESO VLT/VIMOS instrument during two contiguous nights in April 2005, we have detected 333 variables among 84 734 stars in the brightness range 12.7 < V < 26.0 mag. Infrared data collected in March 2010 with the new ESO VISTA telescope allowed us to construct deep combined optical-IR colour-magnitude and colour-colour diagrams. Results. All detected variables but four transit candidates are reported for the first time. The majority of the variables are eclipsing/ellipsoidal binaries and δ Scuti-type pulsators. The occurrence rate of eclipsing/ellipsoidal variables reached ∼0.28% of all stars. This is very close to the highest fraction of binary systems detected using ground-based data so far (0.30%), but still about four times less than the average occurrence rate recently obtained from the Kepler space mission after 44 days of operation. Comparison of the observed K s vs. V − K s diagram with a diagram based on the Besançon model shows significant effects of both distance and reddening in the investigated direction of the sky. We demonstrate that the best model indicates the presence of absorbing clouds at distances 11-13 kpc from the Sun in the minor Carina-Sagittarius arm.

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Section: Discussionsupporting

confidence: 81%

Section: Observations and Data Reductionmentioning

confidence: 99%

Section: The Variablesmentioning

confidence: 99%

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Variability and stellar populations with deep optical-IR images of the Milky Way disc: matching VVV with VLT/VIMOS data

Pietrukowicz

Minniti

Alonso-García

et al. 2012

A&A

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“…All effects that influence the JHK lightcurve are likely also visible in the mid-IR. Our fraction of variable objects with a class III SED is similar (1.8%) to what Wolk et al found. In the optical and near-IR, the fraction of variable field stars is lower than that value (Pietrukowicz et al 2009(Pietrukowicz et al , 2012Wolk et al 2013b).…”

Section: Evolutionary Trends Of the Variabilitymentioning

confidence: 99%

Ysovar: Mid-Infrared Variability in the Star-Forming Region Lynds 1688

Günther

Cody

Covey

et al. 2014

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The emission from young stellar objects (YSOs) in the mid-IR is dominated by the inner rim of their circumstellar disks. We present an IR-monitoring survey of ∼ 800 objects in the direction of the Lynds 1688 (L1688) star forming region over four visibility windows spanning 1.6 years using the Spitzer space telescope in its warm mission phase. Among all lightcurves, 57 sources are cluster members identified based on their spectral-energy distribution and X-ray emission. Almost all cluster members show significant variability. The amplitude of the variability is larger in more embedded YSOs. Ten out of 57 cluster members have periodic variations in the lightcurves with periods typically between three and seven days, but even for those sources, significant variability in addition to the periodic signal can be seen. No period is stable over 1.6 years. Non-periodic lightcurves often still show a preferred timescale of variability which is longer for more embedded sources. About half of all sources exhibit redder colors in a fainter state. This is compatible with time-variable absorption towards the YSO. The other half becomes bluer when fainter. These colors can only be explained with significant changes in the structure of the inner disk. No relation between mid-IR variability and stellar effective temperature or X-ray spectrum is found.

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“…At faint limits the colors of reddened background stars can mimic faint cluster members. This issue can be combated with multiple observations to identify members by variability, since only a tiny fraction of field stars are variable (e.g., Morales-Calderón et al 2009;Pietrukiwicz et al 2009;Wolk et al 2013aWolk et al , 2013b.…”

Section: Introductionmentioning

confidence: 99%

Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

Meng

Rieke

Kim

et al. 2019

ApJ

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We have monitored nearly a square degree in IC 1396A/Tr 37 over 21 epochs extending over 2014-2016 for sources variable in the JHK bands. In our data, 65%±8% of previously identified cluster members show variations, compared with 0.3% of field stars. We identify 119 members of Tr 37 on the basis of variability, forming an unbiased sample down to the brown dwarf regime. The K-band luminosity function in Tr 37 is similar to that of IC 348 but shifted to somewhat brighter values, implying that the K-and M-type members of Tr 37 are younger than those in IC 348. We introduce methods to classify the causes of variability, based on behavior in the color-color and color-magnitude diagrams. Accretion hot spots cause larger variations at J than at K with substantial scatter in the diagrams; there are at least a dozen, with the most active resembling EXors. Eleven sources are probably dominated by intervention of dust clumps in their circumstellar disks, with color behavior indicating the presence of grains larger than for interstellar dust, presumably due to grain growth in their disks. Thirteen sources have larger variations at K than at J or H. For 11 of them, the temperature fitted to the variable component is very close to 2000 K, suggesting that the changes in output are caused by turbulence at the inner rim of the circumstellar disk exposing previously protected populations of grains.

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Deep census of variable stars in a VLT/VIMOS field in Carina

Cited by 7 publications

References 31 publications

Variability and stellar populations with deep optical-IR images of the Milky Way disc: matching VVV with VLT/VIMOS data

Variability and stellar populations with deep optical-IR images of the Milky Way disc: matching VVV with VLT/VIMOS data

Ysovar: Mid-Infrared Variability in the Star-Forming Region Lynds 1688

Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

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