2018A&A...613A...7Y


Query : 2018A&A...613A...7Y

2018A&A...613A...7Y - Astronomy and Astrophysics, volume 613A, 7-7 (2018/5-1)

Scattering linear polarization of late-type active stars.

YAKOBCHUK T.M. and BERDYUGINA S.V.

Abstract (from CDS):

Context. Many active stars are covered in spots, much more so than the Sun, as indicated by spectroscopic and photometric observations. It has been predicted that star spots induce non-zero intrinsic linear polarization by breaking the visible stellar disk symmetry. Although small, this effect might be useful for star spot studies, and it is particularly significant for a future polarimetric atmosphere characterization of exoplanets orbiting active host stars. Aims. Using models for a center-to-limb variation of the intensity and polarization in presence of continuum scattering and adopting a simplified two-temperature photosphere model, we aim to estimate the intrinsic linear polarization for late-type stars of different gravity, effective temperature, and spottedness. Methods. We developed a code that simulates various spot configurations or uses arbitrary surface maps, performs numerical disk integration, and builds Stokes parameter phase curves for a star over a rotation period for a selected wavelength. It allows estimating minimum and maximum polarization values for a given set of stellar parameters and spot coverages. Results. Based on assumptions about photosphere-to-spot temperature contrasts and spot size distributions, we calculate the linear polarization for late-type stars with Teff=3500K-6000K, logg=1.0-5.0, using the plane-parallel and spherical atmosphere models. Employing random spot surface distribution, we analyze the relation between spot coverage and polarization and determine the influence of different input parameters on results. Furthermore, we consider spot configurations with polar spots and active latitudes and longitudes.

Abstract Copyright: © ESO 2018

Journal keyword(s): starspots - stars: activity - polarization - stars: late-type - stars: individual: XX Tri

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 - 2021
#notes
1 V* XX Tri RS* 02 03 47.1138016857 +35 35 28.669244792   9.52 8.42     K0III 121 0

Query : 2018A&A...613A...7Y

Basic data :
V* XX Tri -- Variable of RS CVn type
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:
RS* (), * (HD,AG,...), SB* (CABS,CCABS,...), V* (V*,AAVSO), IR (IRAS,2MASS), PM* (2018yCat), X (1RXS)
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) :
02 03 47.1138016857 +35 35 28.669244792 (Optical) [ 0.0497 0.0424 90 ] A 2018yCat.1345....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) :
02 00 49.3641678278 +35 21 06.639987505 [ 0.0497 0.0424 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) :
139.1059144742322 -24.9978854181276 [ 0.0497 0.0424 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 :
-53.222 -14.160 [0.100 0.087 90] A 2018yCat.1345....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) -26.35 [0.18] / z(~) -0.000088 [0.000001] / cz -26.35 [0.18]
   A 2004MNRAS.349.1069K
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):
5.0820 [0.0497] A 2018yCat.1345....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:
K0III C 2009A&ARv..17..251S
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 (6) :
B 9.52 [0.03] D 2000A&A...355L..27H
V 8.42 [0.01] D 2000A&A...355L..27H
G 7.5552 [0.0053] C 2018yCat.1345....0G
J 5.864 [0.021] C 2003yCat.2246....0C
H 5.331 [0.026] C 2003yCat.2246....0C
K 5.153 [0.016] C 2003yCat.2246....0C
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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The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (24) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

HD 12545 GJ 3130 PPM 66921 TYC 2316-179-1
AG+35 189 GSC 02316-00179 1RXS J020346.9+353527 uvby98 100012545
BD+34 363 HIC 9630 SAO 55233 V* XX Tri
CABS 16 HIP 9630 SBC9 2459 AAVSO 0157+35
CCABS 17 IRAS 02007+3520 SKY# 3032 Gaia DR1 329324417081409664
GEN# +1.00012545 2MASS J02034713+3535286 TIC 63399689 Gaia DR2 329324421377469696

References (121 between 1850 and 2021) (Total 121)
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 : 3    diameter : 1    distance : 1    Fe_H : 1    PLX : 4    PM : 4    MK : 1   

   

Observing logs


IUE : 5   

   


External archives :

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

Data at NED - NASA/IPAC Extragalactic Database : V* XX Tri

Link by name to the catalogue in VizieR :

HD 12545 AG+35 189 BD+34 363 CABS 16 GJ 3130
GSC 02316-00179 HIC 9630 HIP 9630 IRAS 02007+3520 2MASS J02034713+3535286
PPM 66921 1RXS J020346.9+353527 SAO 55233 TYC 2316-179-1 uvby98 100012545
V* XX Tri Gaia DR1 329324417081409664 Gaia DR2 329324421377469696

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2021.09.18-22:15:09

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