J/MNRAS/482/4174 Heliocentric radial velocities of R CrB (Feast+, 2019)
R Coronae Borealis: Radial-velocity and other observations, 1950-2007.
Feast M.W., Griffin R.F., Herbig G.H., Whitelock P.A.
<Mon. Not. R. Astron. Soc. 482, 4174 (2019)>
=2019MNRAS.482.4174F 2019MNRAS.482.4174F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Stars, peculiar ; Equivalent widths ;
Radial velocities
Keywords: stars: peculiar - stars: variables: general - stars: mass-loss -
techniques: radial velocities - stars: carbon -
stars: individual: R CrB
Abstract:
Radial-velocity observations made on more than a thousand nights are
presented for the type star of the R Coronae Borealis (RCB) class.
There are four principal sources: the Lick Observatory (1950 to 1953),
the original Cambridge radial-velocity spectrometer (1968 to 1991),
and the Haute-Provence and Cambridge Coravels (1986 to 1998 and 1997
to 2007, respectively). In the case of the last set the size
(equivalent width) and width (expressed as if Vsin(i)) of the Coravel
cross-correlation (dip) profiles are also given, and the variation and
complexity of those profiles are discussed. Although there is often
evidence of cyclical behaviour in radial velocity, no coherent
periodicity is found in any of the series. From time to time, and
especially over 100 days before the great decline of 2007, the
atmosphere was highly disturbed, with evidence of high-velocity
components. We suggest that those are associated with large turbulent
elements and result in mass ejection to sufficient distances for the
formation of soot and other solids and thus the initiation of RCB-type
declines. We associate the changes in light and radial velocity near
maximum light primarily with the combined effect of such turbulent
elements, and not with coherent pulsation. There is some evidence for
a variation in the mean radial velocity on a time scale of about ten
thousand days.
Description:
Heliocentric radial velocities (Vel) of R CrB and the Modified Julian
Date (MJD) on which they were measured.
Table A1 presents data obtained by G.H. Herbig at the Lick
Observatory during 1950, 1951 and 1953; they are described in section
2.1 of the paper. Note 0.5 indicates an underexposed spectrogram.
Table A2 presents data obtained by R.F. Griffin using various
telescopes coded as follows: 218 Palomar, 303 OHP, 123 ESO, 219 DAO,
202 Original Cambridge, 302 Cambridge Coravel, Uncoded Cambridge
Coravel. An o in the note column indicates that the observation was
made during a faint phase.
Table A3: This details R CrB Cambridge Coravel data (R.F. Griffin)
with recorded profiles: o indicates an observation during a faint
phase, while x indicates an observation during the 2006 period, when
the profiles were abnormal. For each observation, parameters related
to the strength and width of the dip are also given. The strength is
given as an equivalent width (EW), defined exactly as for
line-strengths in stellar spectra except (since the abscissae of a
plotted dip are velocities rather than wavelengths) the units the
km/s rather than wavelength units. The dip width is also expressed as
a velocity, in terms of the Vsin(i) value of the best-matching
rotationally broadened model dip. Note that this is only a shorthand
way of quantifying the dip width and is not intended to imply that the
numbers refer to rotation of the star.
Objects:
-----------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------
15 48 34.41 +28 09 24.3 R CrB = HR 5880
-----------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 26 73 Lick radial velocities
tablea2.dat 30 528 Various radial velocities
tablea3.dat 39 512 Coravel radial velocities and widths
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See also:
J/A+A/353/287 : The R CrB stars (Asplund+, 2000)
J/AJ/134/1877 : Spectropolarimetry of R CrB in 1998-2003 (Kawabata+, 2007)
J/ApJ/747/102 : 12C/13C ratio for 18 galactic R CrB stars (Hema+, 2012)
J/A+A/539/A51 : Catalogue enriched with R CrB stars (Tisserand, 2012)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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4- 11 F8.2 d MJD Modified Julian Date
17- 20 F4.1 km/s HRV Heliocentric radial velocity
24- 26 A3 --- Note [0.5] 0.5=underexposed
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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4- 11 F8.2 d MJD Modified Julian Date
13 A1 --- Note [o] =o faint
17- 20 F4.1 km/s HRV Heliocentric radial velocity
28- 30 I3 --- ObsID ? Observatory code
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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4- 11 F8.2 d MJD Modified Julian Date
17- 20 F4.1 km/s HRV Heliocentric radial velocity
24- 26 F3.1 km/s EW ? strength of dip
28- 31 F4.1 km/s Vsini ? width of dip
39 A1 --- Note [ox] =o faint, =x abnormal
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Acknowledgements:
Patricia Whitelock, paw(at)saao.ac.za
(End) Patricia Vannier [CDS] 23-Dec-2018