J/A+AS/128/29 X-ray/optical observations of A8-G2V stars (Piters+ 1998)
X-ray/optical observations of stars with shallow convection zones (A8-G2 V)
Piters A.J.M., Van Paradijs J., Schmitt J.H.M.M.
<Astron. Astrophys. Suppl. Ser. 128, 29 (1998)>
=1998A&AS..128...29P 1998A&AS..128...29P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Photometry, VBLUW ; Effective temperatures ;
X-ray sources
Keywords: stars: activity; fundamental parameters - X-rays: stars
Description:
Table 1 lists the sample of 173 stars observed for this study. They
are selected from the Bright Star Catalogue (Cat. V/50), with the
following selection criteria:
- Spectral type between A8 and G2; no spectral peculiarities noted;
not double in spectral type classification (e.g., HR 32 with
spectral type F2V+F6V is excluded);
- Luminosity class V;
- Right ascension between 0h and 2h, or between 14h and 24 h,
declination south of +10 degrees (defining the region on the sky
visible during the appointed observation times);
- Binaries for which both components occurred in the BSC are excluded,
if the separation is less than 10". Not listed are five stars for
which no (Walraven photometric and ROSAT X-ray) data are available.
These are HR 591, HR 5542, HR 6593, HR 8245 and HR 8735.
Table 2 lists the Walraven photometric (VBLUW) data for all but four
stars from Table 1. Also listed in Table 2 are the effective
temperature, surface gravity and the reddening, as derived from
comparison with theoretical colours.
Table 5 lists the ROSAT All Sky Survey data for all but 11 stars from
Table 1.
For a description of the Walraven photometric system, see e.g. GCPD/11
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1 23 173 Sample stars
table2 123 169 Walraven photometry data
table5 110 162 ROSAT X-ray data
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- HR HR (Cat. V/50) number
6 A1 --- Note [AB] See Note (1)
8- 12 A5 --- Type Spectral Type (2)
14- 18 F5.2 mag Vmag Apparent visual Johnson V magnitude (2)
20- 23 F4.2 mag B-V Johnson's B-V colour (2)
--------------------------------------------------------------------------------
Note (1): A: No Walraven data available
B: No ROSAT data available
Note (2): Data from HR (Cat. V/50) catalog
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- HR HR number (as in table1)
6 A1 --- Note [*] See Note (1)
8- 15 F8.5 mag VWmag visual (Walraven) magnitude V
17- 23 F7.5 mag e_VWmag standard deviation in VWmag
25- 31 F7.5 mag V-B Walraven colour V-B
33- 39 F7.5 mag e_V-B Standard deviation in V-B
41- 47 F7.5 mag B-U Walraven colour B-U
49- 55 F7.5 mag e_B-U Standard deviation in B-U
57- 63 F7.5 mag U-W Walraven colour U-W
65- 71 F7.5 mag e_U-W Standard deviation in U-W
73- 79 F7.5 mag B-L Walraven colour B-L
81- 87 F7.5 mag e_B-L Standard deviation in B-L
89- 90 I2 --- o_B-L Number of observations
92- 95 I4 K Teff Effective temperature
97- 99 I3 K e_Teff ? Uncertainty in Teff (2)
101-104 F4.2 [cm/s2] logg Logarithm of surface gravity
106-109 F4.2 [cm/s2] e_logg ? Uncertainty in logg (2)
111-116 F6.4 mag E(V-B) The reddening E(V-B)
118-123 F6.4 mag e_E(V-B) ? Uncertainty in E_V-B (2)
--------------------------------------------------------------------------------
Note (1): *: Probably variable: standard deviation of the brightness or one of
the Walraven colours is more than 4 times as large as the average
standard deviation.
Note (2): If the uncertainties are not given, no consistent stellar parameters
could be found by the method applied here (minimum chi-square
larger than 10).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- HR HR number (as in table1)
6 A1 --- Note [U] See Note (1)
8- 11 F4.2 s-1 Count X-ray count rate
13- 16 F4.2 s-1 E_Count ? Positive uncertainty in Count
18- 21 F4.2 s-1 e_Count ? Negative uncertainty in Count
23- 26 F4.2 --- XHR ? Hardness ratio
28- 31 F4.2 --- E_XHR ? Positive uncertainty in XHR
33- 36 F4.2 --- e_XHR ? Negative uncertainty in XHR
38- 42 F5.2 [10+7cm2/J] logCx Log of energy-conversion factor (2)
44- 47 F4.2 [10+7cm2/J] E_logCx ? Positive uncertainty in logCx
49- 52 F4.2 [10+7cm2/J] e_logCx ? Negative uncertainty in logCx
54- 58 F5.2 [cm-2] lognH Logarithm of hydrogen column density
60- 63 F4.2 [cm-2] e_lognH Uncertainty in lognH
65- 69 F5.2 --- logRx Log of Normalized X-ray flux density (3)
71- 74 F4.2 --- E_logRx ? Positive uncertainty in logRx
76- 79 F4.2 --- e_logRx ? Negative uncertainty in logRx
81- 84 F4.2 --- logFx Log of X-ray surface flux density (3)
86- 89 F4.2 --- E_logFx ? Positive uncertainty in logFx
91- 94 F4.2 --- e_logFx ? Negative uncertainty in logFx
96-100 F5.2 --- logLx Logarithmic X-ray luminosity (3)
102-105 F4.2 --- E_logLx ? Positive uncertainty in logLx
107-110 F4.2 --- e_logLx ? Negative uncertainty in logLx
--------------------------------------------------------------------------------
Note (1): U: upper limit values for Count, logRx, logFx, and logLx;
hardness ratio h and the uncertainties (E_h, e_h, E_logRx, e_logRx,
E_logFx, e_logFx, E_logLx, and e_logLx-) are not given (left blank).
Note (2): The unit of the energy-conversion factor CX is: cm^2/ergs, so that
fX = rs / CX is the flux density in ergs/(sec.cm^2) received at
the detector.
Note (3): log Rx = log fX + 0.1(VJ + BC) + 4.574 (BC: bolometric correction)
log Fx = log Rx + 4logTeff - 4.246
log Lx = log Fx + 2log(R*/R☉) + 22.784
--------------------------------------------------------------------------------
Acknowledgements: Ankie Piters
(End) Ankie Piters [Astron. Inst., Amsterdam], Patricia Bauer [CDS] 09-Sep-1997