2000A&A...361..952H


Query : 2000A&A...361..952H

2000A&A...361..952H - Astronomy and Astrophysics, volume 361, 952-958 (2000/9-3)

The history and source of mass-transfer variations in AM Herculis.

HESSMAN F.V., GAENSICKE B.T. and MATTEI J.A.

Abstract (from CDS):

The optical brightness of magnetic cataclysmic variables without accretion discs is a direct measure of the near-instantaneous mass-transfer rates from the late-type secondary stars to the magnetic white dwarfs in these semi-detached binary systems. We derive the mass-transfer history of the magnetic cataclysmic variable AM Herculis from its long-term visual light curve and from bolometric corrections obtained from a number of X-ray observations covering various accretion states. On average, less than 25% of the maximum observed mass-transfer rate occurs. Assuming that the mass-transfer rate is modulated by stellar starspots on the secondary stars, we convert the derived mass-transfer rates into spot filling factors at the L1-point. A statistical model for the coverage fraction and size distribution of random spots near the L1-point in AM Her suggests that the spot filling factor is roughly 0.5 for a fitted power-law distribution of starspot radii, i.e. about half the surface of the star near the L1-point is covered with spots. This density can only be explained if the spottedness of the L1-point is unusual - for instance if spot groups are forced to wander towards the L1-point - or if a large-scale magnetic spot group produced by an α2-dynamo slowly drifts in and out of the L1-region. The former solution predicts that the occurrence of long-term high- and low-states is random and the latter that the long-term light curves of polars are quasi-periodic; the light curve of AMHer may suggest periods of order a decade. Finally, we discuss the relevance of this result to the mass-transfer variations of other cataclysmic variables.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: binaries: general - stars: individual: AM Her - stars: magnetic fields - stars: novae, cataclysmic variables

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 V* AM Her CV* 18 16 13.2546725112 +49 52 04.759613544   15.124 14.808 13.525   M4.5 931 0

Query : 2000A&A...361..952H

Basic data :
V* AM Her -- Cataclysmic Variable 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:
X (2012ApJS,4U,...), * (PLX,UCAC4,...), CV* (2012ApJ), V* (AN,ROTSE1,...), IR (2MASS,WISEA,...), UV (2012ApJS,2EUVE,...), PM* (2018yCat,PM), gam (INTREF), SB* (SBC9), Er* ([GKL99]), dS* (2000AJ)
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) :
18 16 13.2546725112 +49 52 04.759613544 (Optical) [ 0.0285 0.0291 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) :
18 14 58.7451246531 +49 50 55.145333446 [ 0.0285 0.0291 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) :
077.8648119850534 +25.8762500600260 [ 0.0285 0.0291 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 :
-45.970 28.053 [0.037 0.039 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) -19.0 [~] / z(~) -0.000063 [~] / cz -19.00 [~]
   E 1995A&AS..114..269D
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):
11.3484 [0.03] 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:
M4.5 D ~
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 (10) :
B 15.124 [0.35] D 2012yCat.1322....0Z
V 14.808 [0.37] D 2012yCat.1322....0Z
R 13.525 [0.12] E 2012yCat.1322....0Z
G 14.283813 [0.056876] C 2020yCat.1350....0G
J 11.703 [0.023] C 2003yCat.2246....0C
H 11.195 [0.026] C 2003yCat.2246....0C
K 11.002 [0.022] C 2003yCat.2246....0C
g 14.925 [0.35] D 2012yCat.1322....0Z
r 14.624 [0.46] D 2012yCat.1322....0Z
i 14.167 [0.42] D 2012yCat.1322....0Z
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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sedIcon
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 (46) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

4U 1813+50 H 1814+498 SBC9 1041 2XMM J181613.3+495203
2A 1815+500 H 1816+49 SWIFT J1816.1+4951 2XMMi J181613.3+495203
3A 1815+498 INTREF 895 TIC 366122523 XSS J18164+5004
AN 28.1923 LAMOST J181613.21+495205.2 2U 1808+50 [BAG2012] 274.0939+49.8605
1AXG J181611+4952 2MASS J18161324+4952048 3U 1809+50 [BM83] X1814+498
1E 1815.0+4948 2MAXI J1816+498 4U 1814+50 [FS2003] 0963
2E 4051 PBC J1816.0+4952 UCAC4 700-061864 [GKL99] 352
2E 1814.9+4951 PLX 4200.04 USNO 551 AAVSO 1813+49
1ES 1814+49.8 PM J18162+4952 V* AM Her Gaia EDR3 2123837555230207744
2EUVE J1816+49.8 ROTSE1 J181613.28+495205.0 WEB 15248 Gaia DR2 2123837555230207744
EUVE J1816+49.8 RX J1816.2+4952 WISEA J181613.20+495205.0
1H 1814+498 1RXS J181613.8+495203 WISE J181613.20+495205.0

References (931 between 1850 and 2022) (Total 931)
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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                Reference summaries :

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Collections of Measurements


velocities : 1    V* : 2    distance : 2    PLX : 3    PM : 2   

   

Observing logs


herschel : 2    ISO : 12    IUE : 149   

   


External archives :

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

Data at NED - NASA/IPAC Extragalactic Database : V* AM Her

Link by name to the catalogue in VizieR :

2E 4051 EUVE J1816+49.8 2MASS J18161324+4952048 1RXS J181613.8+495203 UCAC4 700-061864
V* AM Her WISEA J181613.20+495205.0 WISE J181613.20+495205.0 [GKL99] 352 Gaia EDR3 2123837555230207744
Gaia DR2 2123837555230207744

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2022.05.27-13:48:23

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