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Details for Revision 2
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Name
  AM Her  
AAVSO UID
000-BCB-802 (86832 observations)  
Constellation
Hercules Sequence
J2000.0
18 16 13.34 +49 52 04.1  (274.05558 +49.86781) Search nearby
B1950.0 18 14 58.66 +49 50 55.9
Galactic coord. 77.865 +25.876
Other names

(Internal only)
Please note that aliases shown in grey link to obsolete records.
AAVSO 1813+49 AN 28.1923 Downes AM Her
NSVS J1816133+495205 ROTSE1 J181613.28+495205.0 X 18149+498
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Variability type
AM/XRM+E
Spectral type pec+M4.5V
Mag. range
12.3 - 15.7 V
Discoverer --
Epoch
24 Aug 1976 (HJD 2443014.71266) Ephemeris
Outburst --
Period 0.128927 d  (3.0942 h)
Rise/eclipse dur. --
Remarks
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1 GCVS Team Ã??U 1809 +50. Lx(soft)/Lopt ~15. Emissions of H and KCaII, H, HeI, HeII, etc. In the spectrum. Epoch of Min I in V light is given. The period shows complex variations. The phase of Min I in U light is 0.30p, in B 0.15P, in R 0.05P. Min I is probably due to an eclipse of a hot spot and the gas flow near the surface of the white dwarf by the white dwarf itself. The depth of Min I is up to 0.7m. Min II with the depth up to 0.4m (sometimes absent), Min II - Min I = 0.55P. Min II coincides in phase with the X-ray eclipse. High and low states (b ~13.0m and B ~15.0m on average); in the high state there are variations with Delta(m) ~0.3m on the time scale >= 200d; the duration of low states is 130d - 700d [R.Hudec, L.Meinunger, MVS 7, H.8, 194, 1977.] or less. During low states the depth of minima is small. Flickering up to 0.8mV in several minutes or dozens of seconds; X-ray flickering on the time scale of ~10s not correlating with optical flickering. The magnetic field ~1*10**7 G at the equator, ~2*10**7 G on poles. Variable circular (from +3% to -9%) and linear (up to 7%) polarization. IR excess at lambda 10 mkm.
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References
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1 ZTF Catalog of Periodic Variable Stars (online data) 2020arXiv200508662C
2 Chen, X.; et al., 2020, The Zwicky Transient Facility Catalog of Periodic
Variable Stars		 2020arXiv200508662C
3 Light curve from CRTS/CSS (Drake et al. 2009, ApJ, 696, 870) 2009ApJ...696..870D
4 R.A. Downes et al., 2001, PASP 113, 764 (2006 archival version) 2005JAD....11....2D
5 R.A. Downes et al., 2001, PASP 113, 764 2001PASP..113..764D
6 C.Akerlof et al., AJ 119, 1901, 2000. 2000AJ....119.1901A
7 P.Szkody, D.E.Brownlee, ApJ 212, L 113, 1977. 1977ApJ...212L.113S
8 W.Liller, Sky and Tel 53, N5, 351, 1977. --
9 Guthnick, P.; et al., 1924, Benennung von neu entdeckten veränderlichen
Sternen		 1924AN....223...41G
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Revision History
Currently approved revision is checked. Click revision number to view details of that revision.
6 Otero, Sebastian Alberto 2024-05-30 04:21 UTC Period from AAVSO V data.
5 Fernig, Leo 2023-07-05 21:44 UTC Discoverer updated from 1924AN....223...41G page 53.
4 Otero, Sebastian Alberto 2021-10-25 22:25 UTC ZTF name from 2020arXiv200508662C added. Gaia EDR3 position.
3 Otero, Sebastian Alberto 2011-05-24 05:55 UTC Type changed.
2 Admin, VSX 2010-01-05 04:43 UTC Position updated from the GCVS version of November 2009.
1 Admin, VSX 2005-12-18 01:33 UTC Initial upload.

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