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J/A+A/372/477       ubvyβ photometry of h & chi Persei  (Marco+, 2001)

Photometric study of the double cluster h & χ Persei Marco A., Bernabeu G. <Astron. Astrophys. 372, 477 (2001)> =2001A&A...372..477M
ADC_Keywords: Clusters, open ; Photometry, uvby, beta Keywords: techniques: photometric - Galaxy: open clusters and associations: individual: h Persei, chi Persei - stars: evolution - emission-line, Be - formation Abstract: We present uvbyβ CCD photometry of the central region of the double cluster h&χ Persei. We identify ≃350 stars, of which 214 were not included in Oosterhof's catalogue. Our magnitude limit V=16.5 allows us to reach early F spectral type and obtain very accurate fits to the ZAMS. We derive reddening values of E(b-y)=0.44±0.02 for h Persei and E(b-y)=0.39±0.05 for χ Persei. From the ZAMS fitting, we derive distance moduli V0-MV=11.66±0.20 and V0-MV=11.56±0.20 for h and χ Persei respectively. These values are perfectly compatible with both clusters being placed at the same distance and having identical reddenings. The shift in the main-sequence turnoff and isochrone fitting, however, show that there is a significant age difference between both clusters, with the bulk of stars in h Persei being older than χ Persei. There is, however, a significant population of stars in h Persei which are younger than χ Persei. All this argues for at least three different epochs of star formation, corresponding approximately to logt=7.0, 7.15 and 7.3. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 02 22 24 +57 07.0 NGC 884 = chi PER 02 19 00 +57 09.0 NGC 869 = h PER ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2a.dat 49 91 *New stars in h Persei (not in Oosterhoff catalog) table2b.dat 49 125 *New stars in χ Persei, not in Oosterhoff catalog table8.dat 82 165 Stromgren photometry of member of h Per table9.dat 82 137 Stromgren photometry of member of χ Per table14a.dat 35 157 Intrinsic photometry of member of h Per table14b.dat 31 132 Intrinsic photometry of member of χ Per
Note on table2a.dat, table2b.dat: Oosterhoff, 1937AnLei..17a...1O
See also: V/27 : Proper Motions and UBV Photometry in h+chi Per (Muminov 1980) Byte-by-byte Description of file: table2a.dat table2b.dat
Bytes Format Units Label Explanations
1- 4 I4 ---- Name Name of the source (1) 7 I1 ---- Frame [1/2] 1 for h Persei and 2 for χ Persei 10- 17 F8.3 pix Xpix X Position in pixel (2) 20- 27 F8.3 arcsec Xpos X Position in arcsec 30- 37 F8.3 pix Ypix Y position in pixel (2) 41- 47 F7.3 arcsec Ypos Y position in arcsec
Note (1): Number references for stars: 4NNN: stars in the field of h Persei 7NNN: stars in the field of χ Persei Note (2): Origin of the coordinates: Frame 1 (h Per): RA = 2 15 9.42 (1950) DE = +56 57 6.87 Frame 2 (chi Per): RA = 2 18 7.58 (1950) DE = +56 57 21.05
Byte-by-byte Description of file: table8.dat table9.dat
Bytes Format Units Label Explanations
1- 4 I4 ---- Name Name of the source (1) 7- 12 F6.3 mag Vmag V magnitude 15- 19 F5.3 mag b-y b-y colour index 22- 27 F6.3 mag m1 m1 colour index 30- 34 F5.3 mag c1 c1 colour index 37- 41 F5.3 mag beta ? β colour index 44- 48 F5.3 mag e_Vmag ? Standard deviation in Vmag 51- 55 F5.3 mag e_b-y ? Standard deviation in b-y 58- 62 F5.3 mag e_m1 ? Standard deviation in m1 65- 69 F5.3 mag e_c1 ? Standard deviation in c1 72- 76 F5.3 mag e_beta ? Standard deviation in beta 79 I1 --- o_uvby Number of measurements in each filter 81 I1 --- o_beta Number of measurement in beta
Note (1): The nomenclature is that of Oosterhoff (1937AnLei..17a...1O). Those stars that were not observed by Oosterhoff (1937AnLei..17a...1O) are listed after a "4" prefix for h Persei field, and a "7" prefix for χ Persei field.
Byte-by-byte Description of file: table14a.dat table14b.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Name Name of the source 6- 11 F6.3 mag V0mag V0 magnitude 13- 18 F6.3 mag (b-y)0 (b-y)0 colour index 20- 26 F7.4 mag c0 c0 index 28- 31 A4 --- SpType Spectral Type (1)
Note (1): Unless otherwise indicated in the text, luminosity class is always taken to be V.
Acknowledgements: Amparo Marco
(End) Patricia Bauer [CDS] 23-Mar-2001
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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