V455 And
V515 And
AE Aqr
FO Aqr
V349 Aqr
XY Ari
V405 Aur
V647 Aur
HT Cam
MU Cam
DW Cnc
V709 Cas
V1025 Cen
V1033 Cas
TV Col
TX Col
UU Col
V2069 Cyg
V2306 Cyg
DO Dra
PQ Gem
V418 Gem
DQ Her
V1323 Her
V1460 Her
V1674 Her
EX Hya
NY Lup
V2400 Oph
V2731 Oph
V3037 Oph
V598 Peg
GK Per
AO Psc
HZ Pup
V667 Pup
WX Pyx
V1223 Sgr
V4743 Sgr
CC Scl
V1062 Tau
AX J1740.1
AX J1832.3
AX J1853.3
CTCV J2056
CXO J174954
IGR J04571
IGR J08390
IGR J15094
IGR J16500
IGR J16547
IGR J17014
IGR J17195
IGR J18151
IGR J18173
IGR J18308
IGR J19267
PBC J0927.8
PBC J1841.1
RX J1804
RX J2015
RX J2113
RX J2133
RX J2306
Swift J0717
Swift J1839
Swift J2006
Swift J2138

Full Catalog

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EI Ursae Majoris = PG 0834+488 = 1H0832+488

Links to this object in VSX and in Swift BAT 157 month survey

A finding chart for EI UMa

SkyView image of EI UMa (see important notes).

  • Equatorial: 08h38m21.99s, +48d38m02.1s (Gaia)
  • Galactic: l=170.88, b=+37.36
Finding Chart:
Green et al. (1982)
Optical: G=14.8 (Gaia); X-rays: 2.9x10-11 ergs cm-2s-1 (BAT 157m; 14-195 keV), 3.6x10-11 ergs cm-2s-1 (4XMM-DR11)
IP Credential:
**** (Confirmed): Although the spin period is rarely seen in optical photometry and only imprecisely measured from X-ray data, the orbital period from spectroscopy and the beat period from optical photometry establish this object to be an IP.
  • Orbital: 0.2681 d = 6.434 hr = 23164 s, seen in optical spectroscopy (Thorstensen 1986). No long-term ephemeris available.
  • Spin: 0.00858 d = 12.36 min = 741.6+/-5.4 s, seen in ASCA data. (Baskill et al. 2005).
  • Others: 0.0089078 d = 12.871 min = 769.63 s sideband period, seen in optical photometry more prominently than the spin (Kozhevnikov 2010).
~23 deg?
1121 (1088-1148) pc (Gaia EDR3 parallax: 0.874+/-0.026 mas)


  1. Green et al. 1982 (optical spectroscopy)
  2. Cook 1985 (X-rays)
  3. Thorstensen 1986 (optical spectroscopy)
  4. Wilson et al. 1986 (optical photometry)
  5. Mukai & Shiokawa 1993 (X-rays)
  6. Baskill, Wheatley & Osborne 2005 (X-rays)
  7. Pandel et al. 2005 (X-ray spectroscopy)
  8. Urban & Sion 2006 (ultraviolet)
  9. Reimer et al. 2008 (X-rays and optical photometry)
  10. Ramsay et al. 2008 (X-rays)
  11. Kozhevnikov 2010 (optical photometry)
  12. Anzolin et al. 2010 (X-ray flickering)
  13. Pretorius, Kingge & Schwope 2013 (space density)
  14. Pretorius & Mukai 2014 (space density)
  15. Schwope 2018 (space density)
  16. Suleimanov, Doroshenko & Werner 2019 (X-ray spectroscopy)
  17. Shaw et al. 2020 (X-ray spectroscopy)
  18. Simon 2021 (optical photometry)

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Please send your comments, suggestions etc. to Koji.Mukai@nasa.gov and/or Koji.Mukai@umbc.edu
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