2018A&A...610A..52B


Query : 2018A&A...610A..52B

2018A&A...610A..52B - Astronomy and Astrophysics, volume 610A, 52-52 (2018/2-1)

The influence of convective blueshift on radial velocities of F, G, and K stars.

BAUER F.F., REINERS A., BEECK B. and JEFFERS S.V.

Abstract (from CDS):

Context. Apparent radial velocity (RV) signals induced by stellar surface features such as spots and plages can result in a false planet detection or hide the presence of an orbiting planet. Our ability to detect rocky exoplanets is currently limited by our understanding of such stellar signals.
Aims. We model RV variations caused by active regions on the stellar surface of typical exoplanet-hosting stars of spectral type F, G, and K. We aim to understand how the stellar magnetic field strength, convective blueshift, and spot temperatures can influence RV signals caused by active regions.
Methods. We use magneto-hydrodynamic (MHD) simulations for stars with spectral types F3V, a G2V, and a K5V. We quantify the impact of the magnetic field strength inside active regions on the RV measurement using the magnetic and non-magnetic FeI lines at 6165Å and 6173Å. We also quantify the impact of spot temperature and convective blueshift on the measured RV values.
Results. Increasing the magnetic field strength increases the efficiency to suppress convection in active regions which results in an asymmetry between red- and blueshifted parts of the RV curves. A stronger suppression of convection also leads to an observed increase in RV amplitude for stronger magnetic fields. The MHD simulations predict convective motions to be faster in hotter stars. The suppression of faster convection leads to a stronger RV amplitude increase in hotter stars when the magnetic field is increased. While suppression of convection increases the asymmetry in RV curves, a decreasing spot temperature counteracts this effect. When using observed temperatures for dark spots in our simulations we find that convective blueshift effects are negligible.

Abstract Copyright: © ESO 2018

Journal keyword(s): techniques: radial velocities - stars: activity - starspots

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 V* EK Dra BY* 14 39 00.2104038120 +64 17 29.979649860   8.243 7.604     G5VFe-0.7CH-1(k) 442 0

Query : 2018A&A...610A..52B

Basic data :
V* EK Dra -- BY Dra Variable
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
* (HD,AG,...), X (2015A&A,1AXG,...), UV (2EUVE,EUVE,...), ** (**,WDS), BY* (2017ARep), SB* (SBC9), Er* ([GKL99]), Ro* (1996ApJ), V* (V*), NIR (2MASS), Opt (SDSS)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
14 39 00.2104038120 +64 17 29.979649860 (Optical) [ 0.0225 0.0200 90 ] A 2020yCat.1350....0G
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
FK4 coord. (ep=B1950 eq=1950) :
14 37 56.3965854170 +64 30 23.590698133 [ 0.0225 0.0200 90 ]
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
Gal coord. (ep=J2000) :
105.5160535706536 +49.0401012036118 [ 0.0225 0.0200 90 ]
Syntax of proper motions is : "pm-ra pm-dec [error ellipse] quality bibcode"
  • pm-ra : mu-ra*cos(dec) (expressed in the ICRS system in mas/yr)
  • pm-dec : mu-dec (expressed in the ICRS system in mas/yr)
  • [error ellipse] : error major axis and minor axis (in mas), orientation angle (in deg)
  • quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality)
  • bibcode : bibcode of the proper motion reference
Proper motions mas/yr :
-135.751 -37.089 [0.030 0.027 90] A 2020yCat.1350....0G
Syntax of radial velocity (or/and redshift) is : "value [error] (wavelength) quality bibcode"
  • value : radial velocity or/and redshift (Heliocentric frame) according to your Output Options
    (redshift may be not displayed if the data value is <0 and the database inside value is a radial velocity)
  • [error] : error of the corresponding value displayed before
  • (wavelength) : wavelength range of the measurement : Rad, mm, IR, Opt, UV, Xray, Gam or  '∼'(unknown)
  • quality : flag of quality ( A=best quality -> E=worst quality, ∼=unknown quality)
  • bibcode : bibcode of the value's origin
Radial velocity / Redshift / cz :
V(km/s) -20.687 [0.0037] / z(spectroscopic) -0.000069 [0.000000] / cz -20.69 [0.00]
   (Opt) A 2018A&A...616A...7S
Syntax of parallax is : 'value quality [error] bibcode'
  • value : parallax value
  • quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality)
  • [error] : mean error
  • bibcode : bibcode of the parallax reference
Parallaxes (mas):
29.0661 [0.0217] A 2020yCat.1350....0G
Spectral type is made of 3 parts: %coding is composed of 4 parts :
  • the spectral type, which is made of a temperature class, eventually a luminosity class (roman number) and/or spectral peculiarities;
  • a quality letter: A=best quality→E=worst quality, {� } =unknown quality %
  • a quality letter: A=best quality -> E=worst quality, {� } =unknown quality
  • bibcode : bibcode of the spectral type reference
Spectral type:
G5VFe-0.7CH-1(k) C 2003AJ....126.2048G
Syntax of fluxes (or magnitudes) is : "filter-name (System) flux-value [error] quality MultVarFlags bibcode"
  • filter-name : U, B, V, R, I, G, J, H, K, u, g, r, i, z
  • (System) : may be AB (default is Vega)
  • flux-value : value of flux or magnitude
  • [error] : error value
  • quality : flag of quality of the flux value ( A=best quality -> E=worst quality, {� } =unknown quality)
  • MultVarFlags : Mult is zero or one char (J) for joined photometry ; Var can be zero or two chars (V[0-4])
  • bibcode : bibcode of the flux reference
Fluxes (11) :
B 8.243 [0.016] D 2000A&A...355L..27H
V 7.604 [0.011] D 2000A&A...355L..27H
G 7.524037 [0.002996] C 2020yCat.1350....0G
J 6.315 [0.020] C 2003yCat.2246....0C
H 6.012 [0.018] C 2003yCat.2246....0C
K 5.914 [0.021] C 2003yCat.2246....0C
u (AB) 12.249 [0.005] C 2009ApJS..182..543A
g (AB) 11.946 [0.005] C 2009ApJS..182..543A
r (AB) 11.227 [0.005] C 2009ApJS..182..543A
i (AB) 11.763 [0.008] C 2009ApJS..182..543A
z (AB) 8.035 [0.001] C 2009ApJS..182..543A
SIMBAD within arcmin
', {sourceSize:12, color:'#30a090'})); aladin.on('objectClicked', function(object) { var objName=object.data.MAIN_ID; aladin.showPopup(object.ra,object.dec,'',''+ objName+''); });" title="Show Simbad objects"> Overlay Simbad points in this preview
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within arcsec The VizieR photometry tool allows for easy visualization of photometry points extracted around the Simbad position from photometry-enabled catalogues in VizieR.
The search radius has to be specified by the user. It is currently limited to a maximum of 30 arcsec. It depends mostly on the precision or quality of the coordinates (SIMBAD and VizieR catalogs), the resolution of the images from which the sources were extracted, source extent, and source crowding.
Suggestions are: crowded field: 0.5 to 1.5 arcsec, 3 arcsec otherwise; uncertain coordinates (SIMBAD quality E or coordinates without reference): 5 to 30 arsec (risky!).
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Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

: 2 : 154 Display criteria :

The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (49) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

HD 129333 GJ 559.1 A RE J1438+641 WDS J14390+6417AB
** KON 1A GJ 559.1 RE J143855+641654 WDS J14390+6417A
AG+64 695 GSC 04176-00540 RX J1439.0+6417 WEB 12346
AGKR 13099 HIC 71631 1RXS J143859.9+641731 2XMM J143900.1+641729
1AXG J143900+6418 HIP 71631 SAO 16453 [FS2003] 0723
BD+64 1017 2MASS J14390026+6417299 SBC9 2553 [GKL99] 306
2EUVE J1438+64.2 PLX 3322 SDSS J143900.24+641730.1 [ZEH2003] RX J1439.0+6417 1
EUVE J1439+64.2 PLX 3322.00 SKY# 26634 Gaia DR2 1668690628102524672
EUVE J1438+64.2 PMC 90-93 3905 SPOCS 608 Gaia DR3 1668690628102524672
GC 19757 PPM 19098 TIC 159613900 Gaia DR1 1668690623807090816
GCRV 8529 RBS 1413 TYC 4176-540-1
GEN# +1.00129333 2RE J143858+641739 uvby98 100129333
GJ 9488 2RE J1438+641 V* EK Dra

References (442 between 1850 and 2024) (Total 442)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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Collections of Measurements


velocities : 10    V* : 2    diameter : 1    distance : 2    ROT : 3    Fe_H : 5    PLX : 6    PM : 7    MK : 4   

   

Observing logs


ISO : 1    IUE : 28    XMM : 1   

   


External archives :

Archive data at HEASARC - High-Energy Astrophysics Science Archive Research Center

Data at NED - NASA/IPAC Extragalactic Database : V* EK Dra

Link by name to the catalogue in VizieR :

HD 129333 AG+64 695 BD+64 1017 EUVE J1439+64.2 EUVE J1438+64.2
GJ 9488 GJ 559.1 A GJ 559.1 GSC 04176-00540 HIC 71631
HIP 71631 2MASS J14390026+6417299 PLX 3322 PPM 19098 2RE J143858+641739
2RE J1438+641 1RXS J143859.9+641731 SAO 16453 SDSS J143900.24+641730.1 TYC 4176-540-1
uvby98 100129333 V* EK Dra WDS J14390+6417AB WDS J14390+6417A [GKL99] 306
Gaia DR2 1668690628102524672 Gaia DR3 1668690628102524672 Gaia DR1 1668690623807090816

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