chepelare, bulgaria, june 1-4, 2010 vii bulgarian-serbian astronomical conference astroinformatics...

.

.

Chepelare, Bulgaria, June 1-4, 2010

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

.

.


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).

.

.


Flare Star Light Curves

LS6=ABC145

14 Jan 1985

Min (pg)=16.75

Max(pg)=15.60

Delta m=1.35

.

.


International Cooperative Programme for Flare Star Searches in 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.

.

.


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

.

.


Total Number of Flare Stars: 1519

564547

10283

5942

17 14 7 14

70

0

100

200

300

400

500

600

Nu

mb

er o

f F

lare

Sta

rs

Flare Stars in Stellar Clusters and Associations

.

.



Total Number of Flare-ups: 3024

827

1635

122 120 146

43 18 21 7 1570

0

200

400

600

800

1000

1200

1400

1600

1800

Orion Pleiades Taurus CygnusI Praesepe Monoceros CygnusII Coma Perseus ScoOphi Others

Num

ber

of F

lare

-ups

.

.



Total Observing Time: 9551 hours

17%

35%

9%

12%

7%

1%3%

4%1%

3%8%

OrionPleiadesTaurusCygnusIPraesepeMonocerosCygnusIIComaPerseusScoOphiOthers

.

.


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).

.

.


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).

.

.


Structure and Content of the FSDBMAIN DATA FILE

Flare-event identifier

Equatorial coordinates (R. A., DEC) of flare star for equinox J2000.0Equatorial coordinates (R. A., DEC) of flare star for equinox J1950.0

Galactic coordinates in the l(II), b(II) systemJulian date of the flare-eventFirst registered flare-event

Telescope usedStellar magnitude at minimum in U or Pg/ BPOSS bands

Stellar magnitudes at maximum in U- and Pg bandsAmplitudes in U and Pg bands

Criterion - m > 5V magnitude, B-V and U-B indices at minimum

Spectral classAggregate membership

Pointers to tables SIMBAD and NOTES

File CROSS-IDENTIFICATIONFile IDENTIFICATION CHARTS

File REFERENCESFile SIMBADFile NOTES

.

.


Flare Stars Identifier

DF CNC 750218

V 426 TAU 711112 1

V 426 TAU 721206 2

.

.


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

.

.


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).

.

.


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.

.

.


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.

.

.


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).

.

.


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).

.

.


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.

Rozhen Flare Stars Digital Plate Archives

.

.


Rozhen Flare Stars Observations:Telescope 50/70/172 cm Schmidt

.

.


50/70/172 cm Schmidt

Main Characteristics

Rozhen Flare Stars Observations:Telescope

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

.

.


Plate Library in Rozhen Observatory

.

.


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.

Rozhen Flare Stars Observations: Number of Plates

.

.


Rozhen Flare Stars Observations: Number of Plates

.

.


Rozhen Flare Stars Observations:Telescope WFPDB ROZ050 Catalogue

.

.


Rozhen Flare Stars Observations: Emulsions and Plate Size

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

.

.


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

Rozhen Flare Stars Digital Plate Archive: Scanners

.

.


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.

.

.


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)

.

.


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.

.

.


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.

.

.


Rozhen Flare Stars Digital Plate Archive: Scanned plates

ROZ050 000291

Gamma Cyg region

.

.


Rozhen Flare Stars Digital Plate Archive : Scanned plates

ROZ050 000383

M42/43 region

.

.


Acknowledgements

This work is supported by the Bulgarian National Science Fund (grant BG NSF DO-02-275).

chepelare, bulgaria, june 1-4, 2010 vii bulgarian-serbian astronomical conference astroinformatics...

Documents

catalogue of flare stars

catalogues of flare

association flare stars

iau flare stars

cygnus flare stars tsvetkov

associations slide

stars of b

flare star searches