J/A+A/531/A8 Activity indices and velocities for 890 stars (Jenkins+, 2011)
Chromospheric activities and kinematics for solar type dwarfs and subgiants.
Jenkins J.S., Murgas F., Rojo P., Jones H.R.A., Day-Jones A.C., Jones M.I.,
Clarke J.R.A., Ruiz M.T., Pinfield D.J.
<Astron. Astrophys. 531, A8 (2011)>
=2011A&A...531A...8J 2011A&A...531A...8J
ADC_Keywords: Stars, nearby ; Stars, dwarfs ; Stars, M-type ;
Radial velocities ; Rotational velocities ; Space velocities
Keywords: stars: fundamental parameters - stars: activity -
stars: kinematics and dynamics - stars: atmospheres -
stars: rotation - planetary systems
Abstract:
In this work we present chromospheric activity indices, kinematics,
radial-velocities, and rotational velocities for more than 850
FGK-type dwarfs and subgiant stars in the southern hemisphere and test
how best to calibrate and measure S -indices from echelle spectra. We
measured our parameters using the high-resolution and high-S/N FEROS
echelle spectra acquired for this purpose. Results. We confirm the
bimodal distribution of chromospheric activities for such stars and
highlight the role that the more active K-dwarfs play in biasing the
number of active stars. We show that the age-activity relationship
does appear to continue to ages older than the Sun if we simply
compare main sequence stars and subgiant stars with an offset of
around 2.5Gyr between the peaks of both distributions. Also we show
evidence of an increased spin-down timescale for cool K dwarfs
compared with earlier F and G type stars.
We highlight that activities drawn from low-resolution spectra
(R<2.500') significantly increase the rms scatter when calibrating
onto common systems of measurements like the Mt. Wilson system. Also
we show that older and widely used catalogues of activities in the
south appear to be offset compared to more recent works at the
∼0.1dex level in logR'HK through calibrator drift.
In addition, we show how kinematics can be used to preselect inactive
stars for future planet search projects. We see the well known trend
between projected rotational velocity and activity, however we also
find a correlation between kinematic space velocity and chromospheric
activity. It appears that after the Vaughan-Preston gap there is a
quick step function in the kinematic space motion towards a
significantly broader spread in velocities. We speculate on reasons
for this correlation and provide some model scenarios to describe the
bimodal activity distribution through magnetic saturation, residual
low level gas accretion, or accretion by the star of planets or
planetesimals. Finally, we provide a new empirical measurement for the
disk-heating law, using the latest age-activity relationships to
reconstruct the age-velocity distribution for local disk stars. We
find a value of 0.337±0.045 for the exponent of this power law, in
excellent agreement with those found using isochrone fitting methods
and with theoretical disk-heating models.
Description:
The activities, rotational velocities, radial velocities and kinematic
space motions are presented for over 850 dwarf and subgiant FGK type
stars. The chromospheric activities were measured using the CaII HK
lines and high resolution and high S/N FEROS spectra. The radial
velocities were determined by cross-correlation with a number of
template stars and the rotational velocities were measured using the
cross-correlation functions from this analysis. The UVW kinematic
space motions were then determined using these radial velocities and
the latest Hipparcos proper motions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 90 890 Stellar basic physical parameters, chromospheric
indices, rotational velocities, radial velocities
and kinematic UVW space velocities
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See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [HIP]
4- 9 I6 --- HIP HIP number
11- 15 F5.3 mag B-V Johnson B-V colour index
17- 20 F4.2 mag Vmag Johnson V magnitude
22- 26 F5.3 --- SMW Mount Wilson activity S-index
28- 32 F5.3 --- e_SMW ? rms uncertainty on SMW
34- 38 F5.2 [---] log(R'HK) Chromopspheric activity index
40- 43 F4.1 km/s vsini ? Rotational velocity
45- 50 F6.1 km/s RV ? Radial velocity
52- 54 F3.1 km/s e_RV ? rms uncertainty on RV
56- 61 F6.1 km/s Uvel ? U kinematic component
63- 66 F4.1 km/s e_Uvel ? rms uncertainty on Uvel
68- 73 F6.1 km/s Vvel ? V kinematic component
75- 78 F4.1 km/s e_Vvel ? rms uncertainty on Vvel
80- 85 F6.1 km/s Wvel ? W kinematic component
87- 90 F4.1 km/s e_Wvel ? rms uncertainty on Wvel
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Acknowledgements:
James S. Jenkins, jjenkins(at)das.uchile.cl
(End) James S. Jenkins [UdeC, Chile], Patricia Vannier [CDS] 12-Apr-2011