IP Catalog Update No. 6

Swift J2006.4+3645 is a BAT source with an optical spectrum typical of IPs. It is considered an "ironclad" IP with the spectroscopic detection of the orbital period and the X-ray and optical photometric detection of the 173 s spin period.
LAMOST J024048.51+195226.9 is a twin of AE Aqr with a 24.9328 s pulsation period.
Swift J0717.8-2156 is a BAT source with an IP-like optical spectrum, a 5.515 h orbital period, and a 803.5 s spin period.
PBC J0927.8-6945 is the optical counterpart of a BAT source whose orbital (4.79 hr), spin (1033 s) and beat (1098 s) periods have been confirmed in X-ray and optical observations.
V1460 Her has been confirmed as an eclipsing IP, with the detection of the 38.9 s spin period in numerous optical photometry runs, following on the original UV detection in HST data. No X-ray confirmation is available, however.
CXOGBS J174954.5-294335 is the optical counterpart of a Chandra X-ray source which is an eclipsing CV. The spin period is seen both in the DECcam and the OGLE data, confirming its status as an IP.
Swift J183920.1-045350 is confirmed as an IP in a comprehensive multi-wavelength study, with the X-ray detection of the 449.7 s spin period and the optical detection of the 459.89 s beat period, although the orbital period is not precisely known.
PBC J1841.1+0138 is an eclipsing, hard X-ray bright CV in which a 311.085 s optical modulation has been detected, thereby confirming its IP status. The 311 s period could be the spin or the sideband period, however.
V1674 Her (Nova Her 2021) is confirmed as an IP with X-ray and optical (both pre-eruption and post) detection of a stable 8.36 min period. Optical photometry also detects 3.67 hr orbital period and sideband periods.
RX J2015.6+3711 is the optical counterpart of a ROSAT source which, in turn, is a partial soft X-ray counterpart of a BAT source. It has a 12.76 hour optical spectroscopic period, and a 7196 s X-ray period, so it has been confirmed as an IP.
CTCV J2056-3014 has a spectroscopic orbital period of 1.76 hr, and X-ray and optical photometric period of 29.6 s; it has been confirmed as a low-luminosity IP.
1RXS J230645.0+550816 is an INTEGRAL source with an optical counterpart that has a CV-like optical spectrum and a 464 s photometric variation. The orbital period is uncertain due to aliasing, however.
Swift J0503.7-2819 is the optical counterpart of a BAT source with 1.36 hr orbital period and a 975 s photometric period. While it is likely to be an IP, an independent confirmation (particularly the detection of the X-ray period) is highly desirable.
Swift J0535.2+2830 is a BAT source with an IP-like optical spectrum with a 1523 s optical photometric period. Orbital period search and the X-ray confirmation of the putative spin period is highly desirable.
Swift J0614.0+1709 is the optical counterpart of a BAT source with 5 hr, 1412 s, and 1530 s periods in optical photometry. While it is likely to be an IP, an independent confirmation (particularly the detection of the X-ray period) is highly desirable.
Swift J0958.0-4208 is a BAT source with an unknown orbital period, a polar-like optical spectrum, and a 296.22 s X-ray period
IGR J14091-6108 is an INTEGRAL (and BAT) source with an unknown orbital period, a CV-like optical spectrum, a CV-like X-ray spectrum, and a 576.3 s X-ray period.
V407 Lup is a 2016 nova which showed a 565 s X-ray period (as well as a 3.57 hr UV/X-ray period) during the supersoft phase. Confirmation during an accretion-powered phase of this system is highly desirable.
IGR J18434-0508 is a hard X-ray discovered CV with an apparent spin period of 152.49 s. An independent confirmation of this, plus a determination of the orbital period, are desirable.
ZTF J185139.81+171430.3 shows a large-amplitude, coherent 12.37 min modulation, and is lumionous enough in X-rays to be a normal IP. Further optical and X-ray observations are necessary to confirm if it is accretion powered, and to establish the orbital period.
2PBC J1911.4+1412 is a hard X-ray source with a CV-like optical spectrum and a 746 s photometric period. Orbital period search and the X-ray confirmation of the putative spin period is highly desirable.
Swift J201424.9+152930 is an eclipsing binary with a 3.4 hr orbital period and a 491 s X-ray period. It is highly likely to be an IP, but the X-ray spectrum (at least the way it was modeled in the only paper dedicated to this object) looks strange for one.
2PBC J0658.0-1746 is a BAT source with an IP-like optical spectrum (but no periods have been identified).
Swift J0749.7-3218 is a BAT source with an CV-like optical spectrum (but no periods have been identified).
2PBC J0819.2-2508 is one of two soft X-ray counterparts of a BAT source with an optical counterpart that appears to be a CV.
SDSS J084617.12+245344.1 has a strong HeII 4686 line and polarization was not detected, so the possibility that this is an IP should be investigated.
Swift J0939.7-3224 is a BAT source with an 8.5 hr spectroscopic period, with a possible photometric period of 2670 s; it is therefore a possible IP.
RZ Leo is a WZ Sge-type dwarf nova which appears to have a 220 s UV photometric modulation.
ASASSN-18fk is a WZ Sge type dwarf nova in which a persistent 22 min photometric period was detected. It's a possible IP but more observations are needed.
IGR J12134-6015, previously missclassified as a beamed AGN, is a hard X-ray source whose optical counterpart is a poorly studied variable star in the Galaxy. A CV identification appears likely, and if so, it may well be an LLIP.
CXO J141430.1-651621 is an X-ray source in which 6120 s and 64200 s periods have been seen, and is a possible IP.
IGR J15038-6021 is an INTEGRAL hard X-ray source whose optical counterpart is Galactic. It has the right X-ray and optical luminosities to be an IP candidate.
1RXS J163100.5+695000 is an optically faint CV with a prominent HeII 4686 line, exhibits high and low states, and is a known X-ray source, making it an IP candidate.
IGR J17040-4305 is an INTEGRAL hard X-ray source whose optical counterpart is Galactic. It has the right X-ray and optical luminosities to be an IP candidate.
ASASSN-15fm is a dwarf nova that showed 18.57 and 20.37 min periods during outburst.
XMMU J175035.2-293557 has shown a 510 s period in the 2017 XMM observation, but this period was undetected during a 2006 Chandra observation.
IGR J18007-4146 is an INTEGRAL hard X-ray source whose optical counterpart is Galactic. It has the right X-ray and optical luminosities to be an IP candidate.
IGR J18017-3542 is an INTEGRAL hard X-ray source that has been identified with a CV. There is little further information.
IGR J18088-2741 is an INTEGRAL source with a CV-like optical spectrum. OGLE data show a 6.84 hr signal, while Chandra data shows a period near 854 s. More data are needed to be confident, but it is a possible IP.
IGR J18112-2641 is an INTEGRAL hard X-ray source whose optical counterpart is Galactic. It has the right X-ray and optical luminosities to be an IP candidate.
IGR J18165-3912 is an INTEGRAL hard X-ray source which is thought to be a CV (in which case it is an IP candidate), or possibly an LMXB.
CXOU J182531.4-144036 is an X-ray source with a 781 s (?) period and also a possible ~5000 s period, and is a possible IP.
IGR J18293-1213 is an INTEGRAL source which shows X-ray eclipses with a 6.92 hr orbital period and a IP-like X-ray spectrum. However, the optical counterpart has not been studied yet and no spin period has been detected in X-ray data so far.
IGR 19173+0747 is an INTEGRAL source previously thought to be a high-mass X-ray binary, based on the blended optical counterpart. The true optical counterpart appears to have a CV-like optical spectrum, so it is a possible IP.
IGR J20084+3211 could be a CV, given what little we know about the object. However, there is a strong possibility it is too luminous to be an IP.
NuSTAR J202421+3350.9 is a serendipitous NuSTAR source whose counterpart has a CV-like optical spectrum.
SRGA J204547.8+672629 has a 2.98 hr period interpreted as the orbital period by the authors, but if so, the optical luminosity is surprising.
Swift J2059.6+4301 B is one of a pair of soft X-ray counterparts of a BAT/INTEGRAL that, together, appear to add up to the right hard X-ray flux. This object (B) appears to be a magnetic CV.
IGR J21095+4322 is an INTEGRAL source with a CV-like optical spectrum, so it may well be an IP. However, so far, no periods have been detected in this system.
Swift J2116.5+5336 is an eclipsing CVs identified with an unpublished BAT source. The eclipse light curves show the presence of a disk. This may be an IP or an unusual non-magnetic CV, given the X-ray connection and the strong He II line.
Gaia18ckw is an optically faint CV that has a blue continuum and the HeII line that is stronger than H-beta, making it an IP candidate.
Gaia19fld is an optically faint CV that with a prominent HeII line, making it a magnetic CV candidate.
SRGA J225412.8+690658 has a relatively modest X-ray luminosity, this CV-like optical counterpart of an SRGA source it could still be a magnetic CV.
2PBC J0658.0-1746, although once proposed as a possible IP, has turned out to be an eclipsing polar.
AT Cnc was seen to have a 26.7 min modulation by Bruch et al., but this is intermittent and was not seen, or seen only as QPOs, by others. The outburst propertes are normal, suggesting a well-developed disk.
IGR J17404-3655, if it is indeed a CV, would be a strong IP candidate owing to its high X-ray luminosity. However, the luminosity may be too high even for an IP, and the optical spectrum is not that of a typical IP either.
IGR J17528-2022, if it is a CV, would be a strong IP candidate owing to its high X-ray luminosity. However, there appears little sign of thermal Fe lines in its X-ray spectrum, and the optical spectrum is not that of a typical IP either.
V1082 Sgr is a long orbital period CV that has a high X-ray luminosity (at least at times). However, there are no reports of credible spin period candidates, including in K2 photometry.
SRGA J194638.9+704552 has a relatively soft X-ray spectrum (not detected with BAT, yet luminous below 10 keV), optically very luminous (suggestive of a long orbital period), and there is no indication of coherent short-period variability so far.
IGR J19552+0044 appears to be an asynchronous polar, with a relatively large asynchronism. It is not known yet if it is approaching synchronism on a human timescale.
Lanning 386 is an unusual eclipsing CV that is not X-ray bright enough to be a normal IP, and the periodogram lacks a clean, convincing peak.

Changes in Confidence Level (37 objects)

TX Col has been upgraded to "ironclad" following the TESS measurements of the orbital, the spin, and the beat period. This is a latest of many independent measurements of all 3 periods.
V418 Gem has been upgraded to "ironclad" since the spin period is seen in X-rays and in optical photometry, and the orbital period is established using optical spectroscopy.
DW Cnc has also been upgraded to "ironclad" since the spin period is seen in X-rays and in optical photometry, and the orbital period is established using optical spectroscopy.
HZ Pup is now considered "ironclad" with the X-ray detection of the 1211 s spin period, coincident with the previously detected optical period, and the spectroscopic period, which confirms the orbital period previously inferred from the spacing of photometric periods.
IGR J15094-6649 has been upgraded to "ironclad" given the multiple independent detection of the spin period, and the fact that the orbital period is measured from optical spectroscopy and hence secure.
IGR J16500-3307 has also been upgraded to "ironclad" given the X-ray detection of the spin period, optical spectroscopic detection of the orbital period, and multiple independent detections of the beat period in optical photometry.
IGR J16547-1916 has also been upgraded to "ironclad" given the X-ray detection of the spin peroid, optical detection of spin and beat periods, and the optical spectroscopic determination of the orbital period.
IGR J17014-4306 has also been upgraded to "ironclad" given multiple independent determination of the eclipse (=orbital) and the spin periods. Only the association with the 1437 guest star is being debated.
IGR J17195-4100 has also been upgraded to "ironclad" with multiple independent detection of the X-ray spin period, with the orbital and beat periods measured using optical spectroscopy and photometry, respectively.
V2731 Oph has also been upgraded to "ironclad" with multiple independent detection of the X-ray spin period as well as optical photometry. The orbital period is from ellipsoidal modulation and optical spectroscopy.
V2731 Her has also been upgraded to "ironclad" given the multiple independent detection of the spin period, including in X-rays, and the spectroscopic determination of the orbital period.
AX J1853.3-0128 has been upgraded to "ironclad" since the orbital period is known from optical spectroscopy and the spin period is seen both in X-rays and in the optical.
IGR J18293-1213 has been upgraded to "ironclad" since the orbital period is known from optical spectroscopy and the spin period is seen both in X-rays and in the optical.
IGR J19267+1325 has been upgraded to "ironclad" since the orbital period is known from optical spectroscopy and the spin period is seen both in X-rays and in the optical.
V2069 Cyg has been upgraded to "ironclad" since the orbital period is known from optical spectroscopy and the spin period has repetedly been detected both in X-rays and in the optical.
Swift J2138.8+5544 has been upgraded to "ironclad" with detection of 4.426 hr orbital period in optical spectroscopy, and the confirmation of 989.4 s spin period (originally seen in X-rays) in optical photometry.
IGR J04571+4527 has been "confirmed" with the detection of 1223 s period, previously seen in the optical, in the X-rays.
UU Col has been downgraded from "ironclad" to "confirmed" since the orbital period has never been measured spectroscopically, and the agreement among the published period values are imperfect.
V2400 Oph has been downgraded from "ironclad" to "confirmed" since the orbital period has never been directly measured, and the accretion mode is not well understood.
1RXS J180431.1-273932 has been "confirmed" with the detection of the 494 s spin period, previously detected in X-rays, as well as the orbital and beat periods, in the K2 data.
IGR J18151-1052 has been "confirmed" with the detection of a 390.5 s X-ray period, which is also seen in optical photometry. However, the orbital period remains unknown.
AX J1832.3-0840 has been "confirmed" with the detection of the 1550 s X-ray period in the optical, even though the orbital period is unknown and the stronger optical period of 2303 s does not have an obvious explanation.
V4743 Sgr is now classified as "confirmed" with the detection of the 0.75 mHz signal in multiple XMM-Newton observations well after the eruption, and re-analysis of the X-ray data during eruption showing the previous report of multiple periods can be explained as due to amplitude modulation of a single period.
V349 Aqr has been "confirmed" with detection of 390.15 s X-ray period, meaning that the previously detected 403.7 s optical period is the sideband period. The orbital period of 3.23 hr is only indirectly seen, however, in the form of the frequently separation of the two.
1RXS J211336.1+542226 is now classifed as "confirmed" with the detection of 4 hr period in the X-rays and optical, and of 21 min and 23 min periods in the X-rays. An independent confirmation (e.g., an optical detection of the spin period) is needed to upgrade the confidence level of the IP classification.
Swift J052522.48+241331.8 is now classified as "probable" with the detection of a 226.3 s X-ray period.
1RXS J080114.6-462324 is now classified as "probable" since the 1310 s X-ray period is also seen in optical photometry (but with many alias peaks), even though the orbital period is unknown and the X-ray spectrum is unusual for a magnetic CV.
IGR J14257-6117 is now classifed as "probable" with the detection of 4 hr (orbital), 509.5 s (spin) as well as 527 s (beat) periods. Given that they all came from a single XMM-Newton observation, an independent confirmation is necessary before upgrading the confidence level.
FS Aur has been downgraded to "doubtful" because a spin period is not seen in repeated observations.
LS Cam has been downgraded to "doubtful" because the previously proposed candidate spin period is not seen in TESS data.
Swift J0706.8+0325 has been downgraded to "doubtful" now that it appears to be a polar.
GI Mon has been downgraded to "doubtful" because a pointed XMM observation did not detect a spin period and appeared to show it to be a non-magnetic system.
Swift J0820.6-2805 has been downgraded to "doubtful" because the low state XMM observation only reveals the ~87 min orbital period securely. Other peaks in the periodogram are not convincing and not consistent with the optical photometry during high state.
V1039 Cen has been downgraded to "doubtful" because the XMM observation did not detect the proposed spin period.
V1084 Her has been downgraded to "doubtful" because a pointed XMM observation did not detect a spin period and appeared to show it to be a non-magnetic system.
V2487 Oph has been downgraded to "doubtful" because repeated X-ray observations have failed to reveal even a hint of a possible spin period.
LS Peg has been downgraded to "doubtful" because observations have failed to show a coherent period that might represent the white dwarf spin. This apepars to be an optically bright nova-like system with a moderate X-ray luminosity.

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IP Catalog Update No. 6

New Variable Star Designations (1 object)

Change in the Name Used in this Catalog (1 object)

Newly Added IPs/IP candidates/non-IPs (61 objects)

Changes in Confidence Level (37 objects)