For this observing program we have selected all stars covering the spectral range from middle F to middle K of luminosity classes IV, III and II listed in "The Bright Star Catalog'' (Hoffleit & Jaschek [1982]; Hoffleit et al. [1983]) and in the list of supergiants compiled by Egret ([1980]), located north of declination zero degrees for the subgiant and giant stars, and north of declination -25 degrees for the bright giant stars. For the luminosity classes IV and III our sample is complete to apparent visual magnitude mv = 6.3 (e.g. Bahcall et al. [1981]), whereas for luminosity class II the sample is complete to apparent visual magnitude mv of about 8.0 (De Medeiros et al. [1999]). To have a better statistics in the spectral region of the Hertzsprung gap and for comparative purposes, we have added several dozen more of F5 to G5 stars of luminosity class III south of zero degrees from "The Bright Star Catalogue''. A systematic radial velocity survey of cool supergiant stars has been carried out in the northern and southern hemispheres for about 10 years (Burki & Mayor [1983]). This survey mostly devoted to a systematic study of binarity and variability will be used here to extend our research towards the Ib and Ib-II luminosity classes. For the latter luminosity classes the sample is complete to apparent visual magnitude mv of about 8.0 (De Medeiros et al. [1999]). With these criteria in hand we prepared a list of approximately 1960 stars. The total number for each luminosity class is:
In addition, a few dozen of G and K active evolved stars nearly brighter
than mv = 8.0 and north of
from Fekel et al. ([1986]) and
Fekel (1997), as well as 4 G5III stars from Alschuler ([1975]) have been
added to the observing list for comparison purposes. Thus, some 2000 evolved stars
were taken for observation, which were selected regardless of binarity characteristics, radial
velocity variations or some peculiarity pointed out in the literature.
The large amount of data presently available allowed a detailed comparative analysis of the spectral classification. To check the different luminosity classes, the classifications of different authors for the classes IV, III, II and Ib were compared from data provided by the CDS "Centre de Données Stellaires'' of Strasbourg Observatory. Essentially we have adopted the classification given by the "Bright Star Catalogue'' for those stars with mv < 6.5, and by Jaschek (1978) for stars with mv > 6.5.
The results presented in this catalog are based on the observations obtained
with the CORAVEL spectrometer (Baranne et al. [1979]), where
the spectrum of a given star is cross-correlated with an adequate
mask located in the focal plane of the instrument. Three free parameters
can be derived from the
resulting cross-correlation function: position of the minimum, half-width at
half-minimum and the cross-correlation area. These parameters are clearly
related to the physical quantities: radial velocity, atmospheric velocity
fields and, in some cases, stellar metallicity. The large majority of the
observations presented here were carried out from March 1986 to May 1994,
except for those stars having a larger time base. All stars north of
declination ,
which represent approximately 80% of our
program stars, were observed with
the CORAVEL mounted on the Swiss 1-meter telescope at the Haute-Provence
Observatory, Saint-Michel (France). The stars south of declination
have been measured
with the southern CORAVEL at the Cassegrain focus of the 1.5 m Danish telescope
at ESO La Silla (Chile).
HD | ![]() |
![]() |
remark |
(Gray) | (COR) | ||
17506 | 6.8 | 5.8 | |
20902 | 17.9 | 16.8 | |
26630 | 7.4 | 8.8 | |
31398 | 3.5 | 3.8 | |
48329 | 7.1 | 8.8 | |
84441 | 4.2 | 5.7 | |
92125 | 4.7 | 7.7 | |
156283 | 3.7 | 1.3 | |
157999 | 3.2 | 4.2 | SB |
159181 | 7.3 | 10.7 | SB |
163770 | 3.4 | 6.3 | |
173009 | 6.5 | 5.1 | SB |
173764 | 5.2 | 7.8 | SB |
177249 | 5.2 | 5.0 | |
180809 | 3.6 | 3.5 | |
183912 | 3.0 | 1.4 | |
185758 | 5.2 | 7.1 | SB |
186791 | 3.2 | 3.8 | |
192876 | 6.2 | 7.3 | |
195295 | 6.4 | 9.5 | SB |
196725 | 0.0 | 2.9 | |
200905 | 1.6 | 3.5 | |
201223 | 5.6 | 7.9 | |
201251 | 3.1 | 6.3 | SB |
204075 | 6.2 | 7.6 | SB |
205349 | 6.7 | 6.4 | |
206731 | 6.2 | 5.2 | |
206778 | 6.5 | 6.0 | |
206859 | 5.7 | 6.1 | |
209750 | 6.7 | 7.8 | |
210745 | 7.8 | 8.0 | |
216206 | 5.8 | 5.4 | |
218356 | 3.9 | 4.4 | SB |
221861 | 7.8 | 7.9 | |
222047 | 7.1 | 6.4 | |
223173 | 4.1 | 4.2 | |
224165 | 3.9 | 2.6 |
HD | ![]() |
![]() |
remark |
(Fekel) | (COR) | ||
1833 | 18.2 | 16.3 | SB |
9746 | 9.0 | 8.7 | |
10909 | 3.0 | 2.7 | SB |
12929 | 1.8 | 1.0 | SB |
17144 | 21.3 | 18.9 | |
23249 | 0.6 | 1.0 | |
25893 | 5.2 | 5.1 | |
26162 | 2.2 | 1.0 | |
28591 | 28.8 | 27.2 | SB |
31993 | 33.4 | 31.1 | |
32357 | 13.1 | 11.5 | SB |
33021 | 0.7 | 2.0 | |
37160 | 0.4 | 1.0 | |
37824 | 14.9 | 13.1 | SB |
39743 | 9.5 | 9.8 | SB |
61421 | 4.9 | 6.1 | SB |
62345 | 2.8 | 1.6 | |
66141 | 2.5 | 1.1 | |
69267 | 4.0 | 2.1 | |
71369 | 3.4 | 4.3 | SB |
80953 | 4.0 | 1.2 | SB |
81410 | 27.1 | 26.1 | SB |
82210 | 5.9 | 5.5 | |
82328 | 6.4 | 8.3 | SB? |
94481 | 2.4 | 2.8 | |
95689 | 3.2 | 1.6 | SB |
104979 | 2.5 | 1.4 | SB |
106225 | 31.3 | 28.8 | SB |
107328 | 4.0 | 1.3 | |
113226 | 3.2 | 2.3 | |
113996 | 3.2 | 1.8 | |
120136 | 14.8 | 15.4 | SB? |
121107 | 15.8 | 14.5 | |
124570 | 4.1 | 5.6 | |
124897 | 3.3 | 1.0 | |
126868 | 15.7 | 14.4 | SB? |
136202 | 4.3 | 4.8 | |
142091 | 0.6 | 1.0 | SB |
142980 | 2.2 | 1.0 | SB |
144284 | 27.7 | 28.0 | SB |
145148 | 0.6 | 1.0 | |
148856 | 3.0 | 4.8 | SB |
150680 | 3.9 | 4.8 | SB |
160538 | 6.7 | 7.2 | SB |
161096 | 2.5 | 1.0 | |
161239 | 6.0 | 5.9 | |
161797 | 1.2 | 1.7 | SB? |
173009 | 6.4 | 5.1 | SB |
173920 | 8.4 | 8.0 | |
175225 | 2.2 | 1.0 | SB? |
176095 | 11.6 | 13.2 | |
180809 | 3.9 | 3.5 | |
181809 | 4.2 | 5.1 | SB |
182572 | 2.6 | 1.7 | |
185510 | 19.6 | 16.0 | SB |
185758 | 6.0 | 7.1 | SB |
HD | ![]() |
![]() |
remark |
(Fekel) | (COR) | ||
188512 | 1.4 | 1.2 | |
188947 | 1.8 | 1.0 | |
196524 | 41.2 | 49.8 | SB |
196755 | 2.7 | 3.3 | |
197964 | 2.9 | 1.0 | |
197989 | 2.0 | 1.4 | SB |
198149 | 0.6 | 1.4 | |
203251 | 46.5 | 44.8 | SB |
208110 | 5.2 | 3.3 | SB |
212943 | 1.0 | 1.0 | |
213389 | 35.7 | 34.4 | SB |
215648 | 7.8 | 7.9 | |
216489 | 28.2 | 25.6 | SB |
217188 | 4.2 | 3.0 | SB |
218153 | 28.9 | 27.1 | SB |
As a rule, we tried to obtain two observations for each program star, separated by approximately one-year intervals, searching for spectroscopic variability. Several new spectroscopic binaries were discovered and, for some stars, the radial velocity variations have been followed up with a suitable cadence to derive the orbital elements. These data will be published in a separate paper which will deal with the spectroscopic binary stars in this program. The radial velocities are derived from a one-Gaussian-curve fitted to the correlation dip obtained with CORAVEL. However, for stars with very wide dips, mostly F stars exhibiting high rotation rates, a parabola is fitted. For double-lined spectroscopic binaries, radial velocities are derived through a fit with two Gaussians. The integration time for a CORAVEL observation in the present survey was typically 5 minutes for the bright stars later than the spectral type G0 and 15 minutes for the earlier ones. For some faint stars, namely mv > 10, as well as blended double-lined spectroscopic binaries, moderate or high rotators, the integration time was typically 15 to 20 minutes.
Although the CORAVEL spectrometer has been initially developed for measuring
high-precision radial velocities of late-type stars, Benz & Mayor
([1981], [1984])
have shown that accurate measurements for dwarf stars could be
deduced from the correlation function of this instrument.
HD | ST | ![]() |
![]() |
(COR) | (Alschuler) | ||
5137 | G5III | 2.0 | 22 |
97561 | G5III | 3.8 | 21 |
127742 | G5III | 5.9 | 26 |
210264 | G5III | 5.0 | 27 |
The general procedure and calibration outlined by Benz & Mayor
([1984]) was
applied here to determine the projected rotational velocities for the present
stellar sample. A comparison with the values determined by Fourier
transform analysis of the lines, allows an estimation
of the effects of macroturbulence acting on stars of different luminosity classes.
This procedure enables us to determine, if necessary, a correction for each
luminosity class to apply to the rotational velocities derived from the standard
calibration established by Benz & Mayor ([1984]). Let us recall that
the Fourier transform technique is the only direct method to deduce both rotation
and macroturbulence (e.g. Gray 1989).
In order to accomplish this study we compare firstly our measurements
with those determined by Gray & Nagar ([1985]) and Gray
([1989]) for the subgiant and giant stars. Table 1 gives the stars with
their rotational velocity values measured respectively by CORAVEL and Gray for
these luminosity classes. A least-squares fit to the data yields the following
relations:
Classes IV and III:
(COR) =
-1.15 + 1.18
(Gray)
)
= 1.3 km s-1
where
)
is the
rms of the rotational velocity differences. This comparison shows
the excellent agreement between CORAVEL
values and those of Gray.
Furthermore, this comparison between CORAVEL
and those
derived by the Fourier transform of a line profile by D. Gray clearly
demonstrates that the original
calibration by Benz & Mayor
([1984])
is valid from luminosity classes V to III.
Taking into account the median error on Gray's measurements (
(Gray) = 0.55 km s-1 for the classes V, IV and III) we have a good
estimation for the CORAVEL external precision of
,
such an external precision
being valid for bright stars of
luminosity classes V to III. Up to magnitude 10 or 11 and typical integration
time, photon noise adds very little to this typical uncertainty.
For luminosity classes II and Ib/Ib-II the increase of the macroturbulence
imposes to adapt a new calibration for the width of the correlation dip
if we are to obtain reliable
values.
In the original calibration, the parameter
is the characteristic
width of the cross-correlation dip of a solar-type star without rotational
broadening. Using the light of the sun reflected by minor planets
Benz & Mayor ([1981]) have derived
km s-1 for the luminosity class V. From the
values
measured by Gray & Toner
([1986], [1987]) for bright giants and Ib supergiants we can
derive
as a function of the luminosity classes. The value
of
is 7.16 and 7.98 km s-1 respectively
for the bright giants
(luminosity class II) and the supergiants of luminosity class Ib/Ib-II (de
Medeiros [1990]).
The values listed in Table 2 have been derived from the
cross-correlation dips using the Benz & Mayor ([1984])
calibration, where the
parameter is a function of the luminosity
class. A least-squares fit of the data gives:
Classes II and Ib:
(COR) = 1.45 + 0.86
(Gray)
) = 1.4 km s-1.
These results show an excellent agreement between CORAVEL measurements
and those from Gray, also for the luminosity classes II and Ib/Ib-II.
If changes in the non-rotational part of the line broadening are not detected
for the luminosity class V to III (
= 6.88 km s-1),
the variation is important for classes II to Ib/Ib-II
with a
= 0.83 km s-1. The
adopted constant value of
by luminosity class will
probably add some
noise to our
measurements as a result of the discreetness of luminosity
classes. However, the external comparison of Fourier transform
and
cross-correlation
shows that the mean square difference is
always about 1.3 to 1.4 km s-1, independently of the
luminosity class. From this comparison we can conclude that for cool bright stars the
cross-correlation and Fourier transform techniques give
measurements
with an equivalent precision of about 1 km s-1 and present
the same lower limit for a significant detection.
The Fourier transform technique has the advantage to allow the distinction
between the rotation and macroturbulence effects on line profiles, but
unfortunately this method requires very high signal-to-noise ratio and is
therefore applicable only to bright stars.
The cross-correlation
technique does not allow separation between rotation and macroturbulence but
has the advantage to be applicable to faint stars. The signal-to-noise ratio
is sufficiently high to analyse accurately the line profile of stars down to
about magnitude 14. Experience has shown that on a 1.5-meter telescope,
using the CORAVEL spectrometer, such a method gives
values for stars
of magnitude 11, within a few minutes, and for stars of magnitude 14, within
an hour, with a precision of 1 km s-1.
We have carried out a similar comparison between CORAVEL values and
those obtained by Fekel et al. ([1986]) for chromospherically
active stars and Fekel ([1997]) for normal stars. Table 3 gives the
list of the stars with their
values measured respectively with CORAVEL
and then by Fekel and collaborators for the luminosity classes IV, III and II.
The relationship between
(COR) and
(Fekel) is given by:
with a rms of the velocity difference of about 1.4 km s-1.
The correlation between the values determined respectively by
CORAVEL and Fekel is clearly as good as that between CORAVEL and
Gray. However, one should be careful here because Fekel has calibrated his
rotational
velocity measurements by using
data from D. Gray and co-workers.
As we have already recalled, prior to the determination
of rotational velocities
by cross-correlation and Fourier transform techniques a few studies employed
somewhat low or moderate spectral resolution to the measurements. In
general, the lowest limit of such measurements was set by the spectral
resolution. We have observed a few stars in common with some of those studies,
which allow a comparison showing clearly that there is no sense to combine
values obtained by cross-correlation or Fourier transform techniques
with those measured by poor or moderate resolution techniques. This is true at
least for
values smaller than about 25 km s-1, as
we can see from Table 4 which shows a comparison between CORAVEL and
Alschuler ([1975])
values.
The radial-velocity uncertainty is derived from an instrumental error
quadratically added to the photon noise and the scintillation noise,
estimated from observational parameters (Baranne et al. [1979]).
At least for the low rotators, which represent the great majority of our
sample, the radial-velocity
measurements
present a precision better than 0.30 km s-1 (see Duquennoy et al.
[1991]). With
an increase of the uncertainty on the radial velocity increases as a
consequence of the decrease of the cross-correlation dip contrast and the
increase of its width.
HD | (B - V) | ST |
2436 | 1.58 | K5III |
5137 | 0.86 | G5III |
5516 | 0.94 | G8IIIb |
8357 | 0.87 | G8IV |
8949 | 1.12 | K1III |
13480 | 0.78 | G5III+F5V |
17904 | 0.41 | FIV |
18894 | 0.60 | G0IV-V |
18925 | 0.70 | G8III+A2V |
23838 | 0.76 | G2III+F2:V |
24546 | 0.41 | F5IV |
29104 | 0.74 | G5II-III+A |
31738 | 0.71 | G5IV |
32453 | 0.88 | G5III |
34029 | 0.90 | G1III/K0III |
37847 | 1.07 | K2III |
38751 | 1.01 | G8IIIv |
40084 | 1.23 | G5III |
41116 | 0.82 | G7III |
43358 | 0.46 | F5IV: |
46178 | 1.07 | K0III |
47415 | 0.53 | F8IV |
47703 | 0.49 | F8III |
56200 | 0.40 | F4II |
57364 | 1.08 | K0II |
58972 | 1.43 | K3III |
59148 | 1.11 | K2III |
59878 | 1.01 | K0II-III+F |
60318 | 1.01 | K0III |
63799 | 1.12 | K1III |
64235 | 0.41 | F5IV |
68461 | 0.89 | G8III |
73596 | 0.40 | F5III |
78418 | 0.66 | G5IV-V |
81873 | 1.04 | K0III |
82543 | 0.62 | F7IV-V |
92787 | 0.33 | F5III |
102509 | 0.55 | G5III-IV+A7V |
106677 | 1.14 | K0III |
109511 | 1.15 | K2III |
115781 | 1.14 | K0III |
122703 | 0.45 | F5III |
123999 | 0.54 | F9IV |
139862 | 0.94 | G8II |
151237 | 0.49 | F8II |
152830 | 0.34 | F5II |
155638 | 1.07 | K0III |
158614 | 0.72 | G9IV-V |
169268 | 0.34 | F6III-IV |
169689 | 0.92 | G8III-IV+A |
169985 | 0.50 | G0III+A6V |
171802 | 0.37 | F5III |
172088 | 0.55 | F9IV |
174881 | 1.18 | K1II-III |
178619 | 0.52 | F5IV-V |
179094 | 1.09 | K1IV |
182549 | 0.90 | G6II |
HD | (B - V) | ST |
184398 | 1.16 | K2II-IIIe |
185151 | 1.25 | K0III |
185734 | 0.97 | G8III-IV |
192577 | 1.18 | K2II+B3V |
196753 | 0.98 | K0II-III+A |
198084 | 0.54 | F8IV-V |
201051 | 1.05 | K0II-III |
202447 | 0.53 | G0III+A5V |
206901 | 0.43 | F5IV |
210334 | 0.72 | G2IV+K0III |
212280 | 0.70 | G0IV-V |
218527 | 0.91 | G8III-IV |
283533 | 0.71 | G0II |
HD/BD | ST |
+01 1876 | F5II |
+20 4010 | F8II |
+33 3998 | F4II |
+37 4115 | F4II |
1671 | F5III |
4758 | F5III |
11443 | F6IV |
17918 | F5III |
23010 | F5II |
34658 | F5II |
36994 | F5III |
48737 | F5III |
55052 | F5III-IV |
72779 | G0III |
77601 | F6II-III |
84607 | F4IV |
104425 | F6II |
108722 | F5III |
110834 | F6IV |
144070 | F5IV |
159026 | F6III |
169985 | G0III+A6V |
192871 | F3II |
194708 | F6III |
203842 | F5III |
208177 | F5IV |
210459 | F5III |
215807 | F5II |
220657 | F8III |
254429 | F8II |
345740 | F4II |
Concerning the rotational velocities the external comparison with Fourier
transform indicates an uncertainty of about 1.0 km s-1 for the CORAVEL of bright stars. For fainter stars we evidently should take into account the
contribution of the photon noise. Nevertheless, as most of our integrations
are relatively long, about 10 minutes or more for faint stars, the
scintillation noise is not dominant. Despite this point, we take into account
these contributions by adopting
where
is determined from the rms
of the different determinations and where
is a lower limit depending on the luminosity class. For classes IV and
III, the
has been conservatively fixed
to 1.0 km s-1. Independently of the excellent agreement of
our
values with the Fourier transform
for bright giant and
supergiant stars, with
)
between 1.3 and
1.4 km s-1, we prefer to adopt
a more pessimistic uncertainty for the luminosity classes II and Ib/Ib-II,
with
= 2.0 km s-1 for both luminosity classes, because it
is not possible to define precisely what are the limits on rotation and
macroturbulence. In this context, such limiting values should be considered only
to set extreme boundaries on the errors, without any physical meaning.
In fact, these uncertainties are adopted for the
values
lower than 30 km s-1 independently of the luminosity class. For rotations above
30 km s-1 the measurement of the dip becomes difficult
(see Benz & Mayor [1981]) and differences between the fitted Gaussian
and such dip are observed. Consequently, the error for
measurements will
be more important than those estimated in the discussion above. For these high
rotators our best estimations indicate an uncertainty of about 10%, these errors
representing the precision with which the Gaussian matches the observations.
Copyright The European Southern Observatory (ESO)