National Aeronautics and Space Administration

IPs

V455 And
V515 And
AE Aqr
FO Aqr
V349 Aqr
XY Ari
V405 Aur
V647 Aur
HT Cam
MU Cam
DW Cnc
BG CMi
V709 Cas
V1033 Cas
V1025 Cen
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
EI UMa
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
LAMOST 0240
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

Related Systems

Confirmed but not Ironclad IPs

V515 And

While the spin period is well established, the orbital period needs to be established using optical spectroscopy.

LAMOST J024048.51+195226.9

This appears to be a propeller system similar to AE Aqr. By my definition, some of the emission must come from accretion onto the magnetic white dwarf (unlike in ). This is likely but an X-ray detection of the spin period would clinch the case.

IGR J04571+4527

Orbital period is uncertain, probably either 6.2 or 4.8 hr.

UU Col

The orbital period is not securely known, including the subtle differences among photometric periods and a lack of spectroscopic measurements.

V647 Aur

It lacks a direct (spectroscopic) determination of the orbital period. Also, the measured spin period derivative appears rather large.

Swift J0717.8-2156

The X-ray detected spin period is only marginally seen in optical photometry (the orbital period is secure).

WX Pyx

The orbital period remains uncertain.

EI UMa

The spin period is not precisely known. A long X-ray observation or a U band optical photometry campaign (the spin periodicity is not strong in redder bands) could do this.

IGR J08390-4833

The orbital period has not been measured yet, thought likely to be around 8 hrs.

PBC J0927.8-6945

It lacks a spectroscopic measurement of the orbital period. The consistency of orbital and siedband periods is there, but only within the relatively large error bars.

V1460 Her

It has been confirmed as an IP in the UV and optical data. A more direct and watertight evidence that the spin-modulated component is accretion powered (perhaps via X-ray observations) is desirable.

V2400 Oph

The orbital period has only been infered through the difference between the spin and the beat periods.

AX J17401-2847

The likely orbital period is from optical photometry, and is not secure.

V3037 Oph

There is a possible 1-day alias problem in the measured orbital period.

CXOGBS J174954.5-294335

This is an eclipsing CV so the orbital period is beyond doubt. The spin period is seen exclusively in the optical data, to date, so an X-ray confirmation is desirable.

1RXS J180431.1-273932

The orbital period is only seen photometrically and not via spectroscopy.

IGR J18173-2508

While the spin period has been confirmed and the orbital period is known from optical spectroscopy, this led to a puzzle: it is a short-period (1.53 h) period system, which should be an LLIP, but in reality it appears rather luminous.

IGR J18308-1232

It has a spectroscopic orbital period (but with possible aliases) and an X-ray (but not optical) spin period. An independent confirmation of the latter, as well as a higher confidence measurements (vis-a-vis aliases) measurement of the former, would be desirable.

Swift J183920.1-045350

This is a recently discovered system that has an X-ray spin period and an optical beat period. A direct spectroscopic determination of the orbital period is necessary, and additional studies of spin and beat period are also desirable.

PBC J1841.1+0138

It is an eclipsing, hard X-ray bright CV in which a 311.085 s optical modulation has been detected. We do not know if the 311 s period is the spin or the beat period, however.

V1674 Her

The likely orbital period is from photometry, which has not been confirmed from spectroscopy.

V4743 Sgr

It has a likely orbital period from photometry, which has not been confirmed from spectroscopy.

RX J2015.6+3711

It has a very long spin period seen in X-rays, long enough to have been considered a polar in one paper; optical confirmation of the spin period is highly desirable.

CTCV J2056-3014

It has all the credentials necessary to confirm it as an IP. It just awaits an independent confirmation for making it "ironclad."

1RXS J211336.1+542226

It has a 4 hr period in the X-rays and optical photometry, as well as 21 min and 23 min periods in the X-rays. While the 4 hr period is presumed to be orbital, it should be confirmed through optical spectroscopy. Also, optical photometry in the high state is highly desirable to confirm the X-ray findings.

V349 Aqr

It has a 390.15 s X-ray period and a 403.7 s optical period, interpreted as the spin period and the sideband period, respectively, establishing this object as an IP. However, the orbital period is only inferred indirectly from these periods.

1RXS J230645.0+550816

This is an INTEGRAL source with an optical counterpart that has a CV-like optical spectrum and a 464 s photometric variation. Unambiguous determination of the orbital period, and X-ray confirmation of the spin period, are both highly desirable.

CC Scl

Its IP credential rests on observatino during a single superoutburst. Further observations, particularly during quiescence, are highly encouraged.

V598 Peg

Its spin period is very close to half the orbital period, even though it is confirmed in X-rays. Longer observations both in the optical and in the X-rays are desirable.

V455 And

Its spin period has been seen only in the optical data to date (it is very X-ray faint).

Laast updated 2026 August 17