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J/A+A/475/677       X-ray emission from A-type stars         (Schroeder+, 2007)

X-ray emission from A-type stars. Schroeder C., Schmitt J.H.M.M. <Astron. Astrophys., 475, 677-684 (2007)> =2007A&A...475..677S
ADC_Keywords: Stars, A-type ; X-ray sources Keywords: X-rays: stars - stars: activity - stars: coronae - stars: general Abstract: Being fully radiative, stars of spectral type A are not expected to harbor magnetic dynamos and hence such stars are not expected to produce X-ray emission. Indeed, while the X-ray detection rate of such stars in X-ray surveys is low, it is not zero and some of the brighter A-type stars have been detected on different occasions and with different instruments. To study systematically the puzzle of the X-ray emitting A-type stars, we carried out an X-ray study of all A-type stars listed in the Bright Star Catalogue using the ROSAT public data archive. We found a total of 312 bright A-type stars positionally associated with ROSAT X-ray sources; we analyzed the X-ray light curves as well as searched for evidence of RV variations to identify possible late-type companions producing the X-ray emission. In this paper we present a list of X-ray active A-type stars, including the collected data about multiplicity, X-ray luminosity and spectral peculiarities. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 102 84 List of X-ray associated "bona fide" single or resolved multiple A-type stars table3.dat 102 226 List of X-ray associated A-type stars in binary or multiple systems or with hints of hidden companions
See also: IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999) IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000) IX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000) III/135 : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989) Byte-by-byte Description of file: table[23].dat
Bytes Format Units Label Explanations
1- 4 I4 --- HR HR number, from the Bright Star Catalog V/50 6- 7 A2 --- Bin Binarity flag (1) 9- 11 I3 km/s vsini ? Rotational velocity or lower value of rotational velocity when interval 12 A1 --- --- [-] 13- 15 I3 km/s vsiniu ? Upper value of rotational velocity when interval 17 A1 --- l_Sep Limit flag on Sep 18- 25 F8.4 arcsec Sep ? Separation for visual binary systems 27 A1 --- --- [/+] 28- 32 F5.1 arcsec Sep2 ? Second value of separation for visual binary systems 33- 34 A2 --- n_Sep2 Note on Separation values 36- 40 F5.1 mag Dmag ? Difference in the magnitude between the star and its closest companion 41 A1 --- --- [/+] 42- 45 F4.1 mag Dmag2 ? Second value of difference in the magnitude between the A star and its closest companion 46- 51 A6 --- n_Dmag Additional informations on Dmag 52- 67 A16 --- SpType MK spectral types of the components 69- 72 I4 pc Dist ?=- Distance of the star as given by Hipparcos (Cat. I/239) parallaxes 74- 76 A3 --- Obs Catalog flag indicating in which observation mode the star has been observed (2) 78- 84 F7.5 ct/s CR Count rate of the associated X-ray source (3) 86- 92 F7.5 ct/s e_CR ?=0.0 Error of the count rate (4) 94-100 F7.1 10+20W LX ?=- X-ray luminosity (5) 102 I1 --- Notes [1/3]? Notes (6)
Note (1): Binary flag as follows: S = single star B = visual or eclipsing binary SB = spectroscopic binary PB = potential binary Note (2): Flags as follows: R = ROSAT all-sky survey P = PSPC pointing H = HRI pointing Note (3): First choice were PSPC pointing source data, second HRI and third survey observation data. Note (4): Errors with a value of 0.0 mark sources with flags in the ROSAT catalogs that indicate a suspect source or false detection in the field. Note (5): X-ray luminosity derived from the distance as given in Col. 7 and the count rates as given in Col. 9. The values are given in units of 1027erg/s (1020W). Note (6): Individual notes as follows: 1 = Simon et al. (1995PASP..107.1034S) calculate an Lx of 33x1027erg/s from PSPC pointing observations. The Second ROSAT Source Catalog of Pointed Observation (2001) lists false detections in the field and therefor no count rate for the source. 2 = In The Second ROSAT Source Catalog of Pointed Observation (2001) this source is flagged as suspect in lightcurve, variability and spectrum. No count rate for the source is listed. 3 = See Zinnecker & Preibisch (1994A&A...292..152Z) and Hamaguchi et al. (2005ApJ...618..360H).
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 31-Dec-2007
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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