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					        VII Bulgarian-Serbian Astronomical Conference
             .
                        ASTROINFORMATICS
             .



Astroinformatics for the Flare Stars in Stellar Clusters and
                       Associations
                           Katya Tsvetkova

                 Institute of Mathematics and Informatics,
                            Institute of Astronomy,
                       Bulgarian Academy of Sciences




                  Chepelare, Bulgaria, June 1-4, 2010
                    .           Flare Star Definition
                    .
Flare activity:
- a very quick increase of the brightness and a decline from maximum to minimum for
some minutes up to some hours;
- a common characteristic in the early evolution of all red dwarf stars.
Belonging:
- to the population of young stellar clusters and associations.
Flare-like activity: some Wolf-Rayet stars, stars of B and A spectral types, RS Cvn
system, some members of Algol and W UMa systems, FK Com stars and even evolved
systems, containing white dwarfs.
All observed characteristics - energy, amplitudes, time-scales, frequencies, shows
differences which could be due to the different origin. That is why collecting flare star
data we have restricted the observed phenomena - so called flares, classical flares,
flashes, microflaring, to the UV Ceti type variability as is classified in the General
Catalogue of Variable Stars (GCVS, Kholopov et al. 1985).

                        Chepelare, Bulgaria, June 1-4, 2010
           .       Flare Star Light Curves
           .

LS6=ABC145
 14 Jan 1985
Min (pg)=16.75
Max(pg)=15.60
Delta m=1.35




               Chepelare, Bulgaria, June 1-4, 2010
                Cooperative Programme for Flare Star Searches in
  International .
                . Stellar Clusters and Associations



Observatories: Tonantzintla, Byurakan, Asiago, Abastumani, Konkoly, Rozhen, etc.
Period: 1960 – 1995.
Wide-field telescopes: Schmidt or Maksutov type.
Method: photographic multi-exposure plate observations by the method of stellar
chains.




                       Chepelare, Bulgaria, June 1-4, 2010
         .                Results
  from the Flare Star Monitoring Optical Observations
         .
           in Stellar Clusters and Associations

Stellar cluster         Number of       Number of          Observing time
 or association         flare stars    registered flares      (hours)

Orion M42/M43                564             827                1591
The Pleiades                 547             1635               3250
Taurus Dark Clouds          102              122                870
Cygnus NGC 7000              83              120                1168
Praesepe                     59              146                680
NGC 2264                     42              43                 105
Cygnus IC 1318               17              18                 300
Coma Open Cluster            14              21                 338
Alpha Persei Cluster         7               7                  128
Scorpius-Ophiuchus           14              15                 321
Others                       70              70                 800

Total1                      1519             3024               9551




                  Chepelare, Bulgaria, June 1-4, 2010
                                                       .
                                                    Flare Stars in Stellar Clusters and Associations
                                                       .


                        600           564
                                                         547


                        500                                                                                                    Total Number of Flare Stars: 1519
Number of Flare Stars




                        400


                        300


                        200

                                                                    102
                                                                                     83
                        100                                                                           59                                                                                         70
                                                                                                                     42
                                                                                                                                       17           14              7             14
                          0
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                                                                   Chepelare, Bulgaria, June 1-4, 2010
                                         .
                                      Flare Stars in Stellar Clusters and Associations
                                         .

                      1800
                                      1635
                      1600
                                                                                      Total Number of Flare-ups: 3024
                      1400
Number of Flare-ups




                      1200

                      1000
                             827
                       800

                       600

                       400

                       200                       122      120        146
                                                                                 43                                                70
                                                                                            18        21        7         15
                         0
                             Orion   Pleiades   Taurus   CygnusI   Praesepe   Monoceros   CygnusII   Coma    Perseus    ScoOphi   Others




                                                Chepelare, Bulgaria, June 1-4, 2010
                .
             Flare Stars in Stellar Clusters and Associations
                .


                            Total Observing Time: 9551 hours
                                                                           Orion
                                                                           Pleiades
                             8%
                                                                           Taurus
                  3%                                           17%         CygnusI
             1%
        4%                                                                 Praesepe
   3%                                                                      Monoceros
 1%
                                                                           CygnusII
7%
                                                                           Coma
                                                                           Perseus
                                                                           ScoOphi
                                                                           Others


     12%                                                             35%


                           9%




                       Chepelare, Bulgaria, June 1-4, 2010
                     Catalogues of Flare Stars
              .
              .

  1. Machine-readable version of the Tonantzintla Pleiades Flare
Stars (Haro+ 1982), Boletin Inst. Tonantzintla 3, No. 1, 3, VizieR
                   Catalogue - II/131 since 1987.
 2. Catalogues of the Cygnus flare stars (Tsvetkov and Tsvetkova,
1990), Proceedings of the 137th Symposium of the IAU Flare Stars
   in Star Clusters Associations and the Solar Vicinity, eds. L. V.
Mirzoyan, B. R. Pettersen and M. K. Tsvetkov, Kluwer Academic
                         Publishers, p. 105.
3. Catalogue of flare stars in the Praesepe cluster (K.P.Tsvetkova,
               M.K.Tsvetkov and I.Jankovics, 1991).



                  Chepelare, Bulgaria, June 1-4, 2010
              .   Flare Stars Database (FSDB)
              .
            Tsvetkova et al. 1995, Tsvetkova et al. 1996

     Database not only for UV Ceti type stars, but also for their
   registered flare-events, which are missing in the other existing
    astronomical catalogues and data sets like GCVS, the Set of
 Identifications, Measurements and Bibliography for Astronomical
Data (SIMBAD), and the Database on UV Ceti Type Flare Stars and
                  Related Objects (for 230 objects) of
                        Gershberg et al. (1993).




                 Chepelare, Bulgaria, June 1-4, 2010
             Structure and Content of the FSDB
                         MAIN DATA FILE
         .                     
         .              Flare-event identifier
Equatorial coordinates (R. A., DEC) of flare star for equinox J2000.0
Equatorial coordinates (R. A., DEC) of flare star for equinox J1950.0
            Galactic coordinates in the l(II), b(II) system
                    Julian date of the flare-event
                     First registered flare-event
                            Telescope used
     Stellar magnitude at minimum in U or Pg/ BPOSS bands
       Stellar magnitudes at maximum in U- and Pg bands
                   Amplitudes in U and Pg bands
                         Criterion - m > 5
          V magnitude, B-V and U-B indices at minimum
                            Spectral class
                       Aggregate membership
              Pointers to tables SIMBAD and NOTES
                                
                    File CROSS-IDENTIFICATION
                   File IDENTIFICATION CHARTS
                          File REFERENCES
                             File SIMBAD
                              File NOTES
              Chepelare, Bulgaria, June 1-4, 2010
                   Flare Stars Identifier
        .
        .




DF                  CNC           750218
V 426               TAU            711112         1
V 426               TAU           721206          2




            Chepelare, Bulgaria, June 1-4, 2010
         .
FSDB                 RA Dec      RA Dec       Date
         .
Identifier           (1950)       (2000)

V1581CYG750706 1953.9+4425 1952.3 +4417 19750706001
V1513CYG710730 2005.1+5427 2003.9 +5418 19710730002
V1513CYG710731 2005.1+5427 2003.9 +5418 19710731002

V 426TAU690918     033042+2226             19690918001
V 426TAU711112     033042+2226             19711112002
V 426TAU721206     033042+2226             19721206003
V 594TAU730226     033042+2308             19730226001
V 485TAU681019     033048+2250             19681019001

DF   CNC750218    083524 +1815             19750218007
DF   CNC750313    083524 +1815             19750313007
DF   CNC750402    083524 +1815             19750402007
DF   CNC760228    083524 +1815             19760228007
DF   CNC760325    083524 +1815             19760325007
DF   CNC760330    083524 +1815             19760330007
DF   CNC800319    083524 +1815             19800319007

             Chepelare, Bulgaria, June 1-4, 2010
                 . Flare Stars Database: Problems
                 .

   A most serious obstacle for the FSDB is the lack in the literature for
some stars of some necessary parameters of the flare-event: beginning of
 flare-events, duration, flare star identification charts, in the GCVS the
    information on stellar magnitude at minimum and maximum is not
sufficient for assigning the flare event parameters. Very often, the lack of
  flare star identification charts is a reason for some missidentifications
              and errors here (Tsvetkova and Tsvetkov, 1989).




                   Chepelare, Bulgaria, June 1-4, 2010
                        .   Automated Flare Stars Search:
                        .             Results
When the plates are compared with a blink-comparator a selection effect due to the used 10-minute
duration of the single exposure, which is a low time resolution, appears. Thus it may preclude detection
of energetic, but low amplitude flare-events on bright stars. The flare star surveys with used flare star
monitoring photographic method of multi-exposure images each of 10-minute duration usually
discover the most chromospherically active stars. The less active stars could be missed. If the star is
very faint it will be impossible to observe small flares.

•An automated flare stars search method was applied for some
southern stellar aggregates with different age (Aniol et al. 1990,
Winterberg et al. 1995).
•This procedure removes partially the selection effect and increases
the number of discovered flares by 50 % compared to visual
inspection by a Zeiss-comparator.
•The number of slow flare events, flares on bright stars and on In-
type variables was mainly increased.

                            Chepelare, Bulgaria, June 1-4, 2010
                   .         Digital Plate Archives
                   .

According to the main observing programmes:
Aims: to assemble and explore massive data sets in order to reveal a new knowledge
existing in the data, but still not recognized in any individual data set.
Preparation of digital plate archives - as a part of the long-time
programme for search, preservation and re-usage of the world wide-
field photographic astronomical plate collections.
The last step before the systematic astronomical research:
The organization of the plate scans in an image database and the
development of a software system for object plate identifications and for
searching in an image database with many data storage variants as
current tasks.



                       Chepelare, Bulgaria, June 1-4, 2010
                    . Digital Plate Archives: Examples
                    .
•The Pleiades Plate Database - about 3100 plates obtained in the period 1885
– 1998 were found in the observatories in Asiago (Italy), Sonneberg (Germany),
Harvard (USA), Kyiv (Ukraine), Moscow (Russia), Rozhen (Bulgaria), Konkoly
(Hungary), Byurakan (Armenia), Potsdam (Germany), Edinburgh (UK), Bamberg
(Germany). It gives the opportunity to obtain almost continuous photometric data set for
the red dwarf stars in the cluster.
The precise coordinates of the known Pleiades flare stars were determined as a
necessary step to the further work of automated search for long-term brightness
variations.
The archive of the digitised plates in the Pleiades stellar cluster contains already about
1500 plates. The plate images are included into the developed Pleiades Plate Data Base
(PPDB, Borisova et al. 2003; Tsvetkov et al. 2005).




                       Chepelare, Bulgaria, June 1-4, 2010
                       Digital Plate Archives: Examples
                 .
•Konkoly Supernova Digital Plate Archive (Tsvetkova et al. 2008, Baltic Astronomy) -
                 .
observing programmes carried out with the 60/ 90/180 cm Schmidt telescope, started at
the end of 1963, with which Konkoly Observatory for about more than a 30-year period
took part in the international campaign initiated by F. Zwicky.

•Konkoly Flare Star Digital Archive – of representative plates obtained with the
Schmidt telescopes of Konkoly observatory during the observation campaign for search
and investigations of the flare stars in stellar clusters and associations in 1970-1990.
Besides the primary aim to serve for investigations of the flare stars another result is
the realization of an interlinking the electronic Information Bulletin on Variable Stars
(IBVS) with the Wide-Field Plate Database (WFPDB). The plates are scanned with
resolution 1200 dpi for plate visualization and to preserve the observer marks. The
image is saved as TIFF file format with size 51.12MB and as JPEG file (compressed to
2000x2000 pixels) with size 1.65MB. After the cleaning the observer marks the plate is
scanned with high resolution (2400 dpi) and saved as FITS file with size 409 MB.

•Carte du Ciel Plate Digital Archives – Uccle (Tsvetkova et al. 2007),
Potsdam (Tsvetkova et al. 2009, Astronomische Nachrichten).

                       Chepelare, Bulgaria, June 1-4, 2010
                Rozhen Flare Stars Digital Plate Archives
                 .
                 .


Now having at disposal an observing material from the monitoring flare star
observations in the Rozhen Observatory, done with the 50/70/172 cm Schmidt
telescope in the period 1979 – 1994, we are going to apply an automated flare stars
search method on the basis of scanned flare stars monitoring plates of the Rozhen
Observatory.




                     Chepelare, Bulgaria, June 1-4, 2010
Rozhen Flare Stars Observations:Telescope
  .
          50/70/172 cm Schmidt
  .




    Chepelare, Bulgaria, June 1-4, 2010
Rozhen Flare Stars Observations:Telescope
  .
          50/70/172 cm Schmidt
  .




    Chepelare, Bulgaria, June 1-4, 2010
           Rozhen Flare Stars Observations:Telescope
              .
              .

                            50/70/172 cm Schmidt
                              Main Characteristics

 WFPDB Tel.Orig. Aperture Focal     Scale Tel. Field     Years of   Plate
Instr. Ident. Name (m)    Length (m) "/mm Type Size (deg) Operation Number


ROZ050     Schmidt   0.50/0.70 1.72   120   Sch      4.5   1979-1994   7348




                     Chepelare, Bulgaria, June 1-4, 2010
Plate Library in Rozhen Observatory
.
.




  Chepelare, Bulgaria, June 1-4, 2010
                . Rozhen Flare Stars Observations:
                .          Number of Plates
   Stellar clusters and associations: the Pleiades, Gamma Cygni
region, M42/43 in Orion, Praesepe, Alpha Per, Tauri Dark Clouds,
   the open cluster NGC 2264, the emission nebula NGC 7000.
             Number of Plates: totally 1564 plates.




                Chepelare, Bulgaria, June 1-4, 2010
. Rozhen Flare Stars Observations:
.        Number of Plates




  Chepelare, Bulgaria, June 1-4, 2010
Rozhen Flare Stars Observations:Telescope
  .   WFPDB ROZ050 Catalogue
  .




    Chepelare, Bulgaria, June 1-4, 2010
  Rozhen Flare Stars Observations:
.    Emulsions and Plate Size
.




     Used emulsions: ORWO, Kodak
     Plate Size: 13x13 cm; 16x16 cm




  Chepelare, Bulgaria, June 1-4, 2010
          Rozhen Flare Stars Digital Plate Archive: Scanners
                .
                .



Sofia Sky Archive Data Center:
PDS1010plus microdensitometer with possibility for high precision;
Flatbed Scanner: EPSON EXPRESSION 1640XL
Flatbed Scanner: EPSON PERFECTION V700 PHOTO



Rozhen Observatory:
Flatbed Scanner: EPSON EXPRESSION 10000XL




                      Chepelare, Bulgaria, June 1-4, 2010
               Sofia Sky Archive Data Center: FB Scanner
                  .
                  .

EPSON EXPRESSION
1640XL
Scanning platform:
310x437 mm;
Resolution: 1600x3200dpi,
Duration: 5min 16x16 cm
plate;
Plate Storage: FITS with
volume 120 MB.




                       Chepelare, Bulgaria, June 1-4, 2010
                       . Rozhen Observatory: FB Scanner
                       .
EPSON EXPRESSION
10000XL
Scanning platform:310x437
mm
Resolution: 1600x3200dpi
Duration: 5min 16x16 cm
Plate Storage: FITS


2m RCC plates 30x30 cm
Previews:Adobe Photoshop
600dpi, 24bit colour
TIFF; JPEG
Scans: Scanfits
1600dpi, 16bit grayscale
FITS (612MB)




                           Chepelare, Bulgaria, June 1-4, 2010
          Rozhen Flare Stars Digital Plate Archive: Scanning
                .
                . Main parameters of the available flatbed scanners
    Scanner              Dmax     Color depth   Grayscale depth   Resolution (dpi)


         1640XL    3.6              42/42              14/14           1600
         10000XL         3.8        42/42              16/16      2400x4800




The used software for scanning is the standard one for making preview images - Adobe
Photoshop, and the programme Scanfits for the real scans in FITS format.




                         Chepelare, Bulgaria, June 1-4, 2010
           Rozhen Flare Stars Digital Plate Archive: Scanning
                 .
                 .
Preview images: aim: easier web accessibility and to store the information from the
observer’s marks on the plate a system for quick plate visualization
Parameters: 1200 dpi in TIFF format and compressed 1000x1000 pxl JPEG format;
color depth:    8-bit 24 bit Color
Real scans:
Scanning Parameters: 2400 dpi, FITS format, density range (0 – 255) and Gamma =
1.00; color depth - 16-bit Grayscale.




                      Chepelare, Bulgaria, June 1-4, 2010
  Rozhen Flare Stars Digital Plate Archive: Scanned plates
          .
          .
 ROZ050 000291
Gamma Cyg region




             Chepelare, Bulgaria, June 1-4, 2010
Rozhen Flare Stars Digital Plate Archive : Scanned plates
           .
           .
 ROZ050 000383
 M42/43 region




              Chepelare, Bulgaria, June 1-4, 2010
            .
            .
                     Acknowledgements
This work is supported by the Bulgarian National Science
           Fund (grant BG NSF DO-02-275).




                Chepelare, Bulgaria, June 1-4, 2010

				
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