2000A&A...358..956P


Query : 2000A&A...358..956P

2000A&A...358..956P - Astronomy and Astrophysics, volume 358, 956-992 (2000/6-3)

2-D non-LTE models of radiation driven winds from rotating early-type stars. I. Winds with an optically thin continuum.

PETRENZ P. and PULS J.

Abstract (from CDS):

We extend previous 2-D models of line-driven winds from rotating hot stars by accounting for the dependence of ionization structure and occupation numbers on local physical properties (density, velocity field) and the non-local stellar radiation field. For this purpose, we formulate for the first time an approximate non-LTE description of 2-D winds. We propose the concept of a ``mean irradiating atmosphere'', which allows one, in a computationally effective way and for all locations in the stellar wind, to consider the frequency dependence of the incident photospheric radiation field, which decisively determines the local ionization equilibrium. Employing 2-D NLTE occupation numbers, force-multipliers and according force-multiplier parameters as functions of (r, Θ), our hydrodynamic models are entirely self-consistent. To estimate maximum effects arising from rotation and a consistent non-LTE approach, we concentrate on rapidly rotating B-star winds, since for this spectral regime the ionization structure is most sensitive to local conditions and variations of the radiation field. In order to avoid any contamination by the bi-stability effect (Lamers & Pauldrach, 1991), we further restrict ourselves to winds with an optically thin Lyman continuum. For all considered models, we find a prolate wind structure if gravity darkening and non-radial line forces are accounted for. Thus, the ``κ-effect'' suggested by Maeder (1999A&A...347..185M), aiming at the possibility to obtain an oblate wind morphology, is actually not present for winds with an optically thin continuum. This result should be valid at least in the OB-star range, excluding B-supergiant winds close to the bi-stability jump. The density contrast between the polar and the equatorial flow grows with rotation rate and decreases from thin winds ({dot}(M)>10–8M/yr: ρpeq≲20...30) to denser ones ({dot}(M)>10–6M/yr^: ρpeq≲5). The latter values are valid for winds rotating at 85% of the break-up velocity. The variation of terminal velocity as function of latitude, however, is only small. In comparison to simplified models with global averages for the force-multiplier parameters, the selfconsistent calculation results in a density contrast ρpeq larger by roughly a factor of two, with a moderately enhanced concentration of wind material over the poles and a significant reduction in the equatorial plane. This difference is shown to be the consequence of ionization effects, related to the specific radial dependence of the mean radiation temperature over the poles and about the equatorial plane, respectively. We conclude that a quantitatively correct description of line-driven winds from rapidly rotating hot stars requires a self-consistent approach if the variation of Trad(Θ) at the stellar surface can induce a (significantly) stratified ionization equilibrium and should be included especially for B-stars with lower luminosities and thinner winds. Our most important finding with regard to the influence of rotation on global wind properties is that the total mass-loss rate {dot}(M)total deviates from its 1-D value {dot}(M)1–D (for vrot=0) by at most 10...20%, even for very high rotation rates (vrot≲0.85vcrit), except for winds from supergiants close to the Eddington-limit, where differences up to a factor of 2 become possible. We explain this remarkable coincidence by appropriate scaling relations and finally discuss our results with special emphasis regarding the wind-momentum luminosity relation of rapidly rotating stars.

Abstract Copyright:

Journal keyword(s): hydrodynamics - methods: numerical - stars: circumstellar matter - stars: early-type - stars: mass-loss - stars: rotation

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 - 2022
#notes
1 HD 93521 * 10 48 23.5113981120 +37 34 13.083332412 5.67 6.79 7.03     O9.5IIInn 412 1

Query : 2000A&A...358..956P

Basic data :
HD 93521 -- Star
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,...), IR (2MASS), UV (TD1), X (3XMM)
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) :
10 48 23.5113981120 +37 34 13.083332412 (Optical) [ 0.0520 0.0615 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) :
10 45 33.5850626957 +37 50 04.571182941 [ 0.0520 0.0615 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) :
183.1403030377946 +62.1520254795529 [ 0.0520 0.0615 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 :
0.389 2.131 [0.072 0.084 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) -14.10 [3.2] / z(~) -0.000047 [0.000011] / cz -14.10 [3.20]
   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):
0.7837 [0.0806] 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:
O9.5IIInn C 2011ApJS..193...24S
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 5.67 [~] D 2003AJ....125.2531R
B 6.79 [0.01] D 2000A&A...355L..27H
V 7.03 [0.01] D 2000A&A...355L..27H
G 6.973444 [0.002810] C 2020yCat.1350....0G
J 7.499 [0.020] C 2003yCat.2246....0C
H 7.647 [0.016] C 2003yCat.2246....0C
K 7.696 [0.024] 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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Some important notes on this object about identifications and objects associations.
notes:

  • WDS J10484+3734 exists only in the notes of the WDS, but is not listed as a binary in the main catalog.


The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (29) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

HD 93521 GEN# +1.00093521 PPM 75477 uvby98 100093521
AG+37 1080 GOS G183.14+62.15 01 ROT 1614 WEB 9621
AGKR 9692 GSC 03009-02547 SAO 62257 3XMM J104823.5+373412
ALS 14745 HGAM 599 SKY# 20691 Gaia DR2 775029739076581248
BD+38 2179 HIC 52849 TD1 15137 Gaia EDR3 775029739076581248
CGO 254 HIP 52849 TIC 8262242
GC 14866 2MASS J10482352+3734130 TYC 3009-2547-1
GCRV 6718 MCW 551 UBV M 16509

References (412 between 1850 and 2022) (Total 412)
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 : 4    ROT : 1    Fe_H : 1    PLX : 4    PM : 7    MK : 8   

   

Observing logs


IUE : 675   

   


External archives :

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

Link by name to the catalogue in VizieR :

HD 93521 AG+37 1080 ALS 14745 BD+38 2179 GSC 03009-02547
HIC 52849 HIP 52849 2MASS J10482352+3734130 PPM 75477 SAO 62257
TD1 15137 TYC 3009-2547-1 uvby98 100093521 Gaia DR2 775029739076581248 Gaia EDR3 775029739076581248

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2022.05.25-19:06:12

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