2016A&A...594A..75K


Query : 2016A&A...594A..75K

2016A&A...594A..75K - Astronomy and Astrophysics, volume 594A, 75-75 (2016/10-1)

The nature of the light variability of magnetic Of?p star HD 191612.

KRTICKA J.

Abstract (from CDS):

Context. A small fraction of hot OBA stars host global magnetic fields with field strengths of the order of 0.1-10kG. This leads to the creation of persistent surface structures (spots) in stars with sufficiently weak winds as a result of the radiative diffusion. These spots become evident in spectroscopic and photometric variability. This type of variability is not expected in stars with strong winds, where the wind inhibits the radiative diffusion. Therefore, a weak photometric variability of the magnetic Of?p star HD 191612 is attributed to the light absorption in the circumstellar clouds.
Aims. We study the nature of the photometric variability of HD 191612. We assume that the variability results from variable wind blanketing induced by surface variations of the magnetic field tilt and modulated by stellar rotation.
Methods. We used our global kinetic equilibrium (NLTE) wind models with radiative force determined from the radiative transfer equation in the comoving frame (CMF) to predict the stellar emergent flux. Our models describe the stellar atmosphere in a unified manner and account for the influence of the wind on the atmosphere. The models are calculated for different wind mass-loss rates to mimic the effect of magnetic field tilt on the emergent fluxes. We integrate the emergent fluxes over the visible stellar surface for individual rotational phases, and calculate the rotationally modulated light curve of HD 191612.
Results. The wind blanketing that varies across surface of HD 191612 is able to explain a part of the observed light variability in this star. The mechanism is able to operate even at relatively low mass-loss rates. The remaining variability is most likely caused by the flux absorption in circumstellar clouds.
Conclusions. The variable wind blanketing is an additional source of the light variability in massive stars. The presence of the rotational light variability may serve as a proxy for the magnetic field.

Abstract Copyright: © ESO, 2016

Journal keyword(s): stars: winds, outflows - stars: mass-loss - stars: early-type - stars: variables: general - hydrodynamics

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 - 2023
#notes
1 HD 191612 SB* 20 09 28.6105997664 +35 44 01.286453904 7.40 8.07 7.80     O8fpe 235 0

Query : 2016A&A...594A..75K

Basic data :
HD 191612 -- Spectroscopic Binary
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:
* (2012ApJ,HD,...), SB* (2007MNRAS), X (1RXS,2XMM), UV (CEL,TD1), gam ([AAA2018]), NIR (2MASS)
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) :
20 09 28.6105997664 +35 44 01.286453904 (Optical) [ 0.0172 0.0208 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) :
20 07 35.4364216387 +35 35 08.541445519 [ 0.0172 0.0208 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) :
072.9916633670707 +01.4343903775535 [ 0.0172 0.0208 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 :
-3.164 -5.693 [0.024 0.028 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) -27.60 [3.3] / z(~) -0.000092 [0.000011] / cz -27.60 [3.30]
   C 2006AstL...32..759G
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):
0.5362 [0.0244] 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:
O8fpe C 2007MNRAS.381..433H
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 (7) :
U 7.40 [~] C 2002yCat.2237....0D
B 8.07 [~] C 2002yCat.2237....0D
V 7.80 [~] C 2002yCat.2237....0D
G 7.709889 [0.002839] C 2020yCat.1350....0G
J 7.122 [0.024] C 2003yCat.2246....0C
H 7.12 [0.04] C 2003yCat.2246....0C
K 7.034 [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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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.
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Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

: 1 Display criteria :

The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (34) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

HD 191612 GSC 02683-03518 1RXS J200928.9+354410 uvby98 100191612
AG+35 1969 HIC 99308 SAO 69520 WEB 17713
ALS 10885 HIP 99308 SKY# 37925 2XMM J200928.6+354401
BD+35 3995 LF 3a +35 261 TD1 26170 [AAA2018] FGL J2009.9+3544
CEL 4952 LS II +35 54 TIC 378273410 Gaia DR3 2059130368252069888
CGO 559 2MASS J20092859+3544011 TYC 2683-3518-1 Gaia DR1 2059130363933775104
GCRV 12516 MCW 811 UBV 17380 Gaia DR2 2059130368252069888
GEN# +1.00191612 PPM 84335 UBV M 24571
GOS G072.99+01.43 01 ROT 2924 UCAC3 252-207877

References (235 between 1850 and 2023) (Total 235)
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 : 7    distance : 2    ROT : 5    PLX : 4    PM : 4    MK : 11   

   

Observing logs


IUE : 2   

   


External archives :

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

Link by name to the catalogue in VizieR :

HD 191612 AG+35 1969 ALS 10885 BD+35 3995 CEL 4952
GSC 02683-03518 HIC 99308 HIP 99308 LF 3a +35 261 LS II +35 54
2MASS J20092859+3544011 PPM 84335 1RXS J200928.9+354410 SAO 69520 TD1 26170
TYC 2683-3518-1 UCAC3 252-207877 uvby98 100191612 Gaia DR3 2059130368252069888 Gaia DR1 2059130363933775104
Gaia DR2 2059130368252069888

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2023.09.27-17:25:11

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