February 2023 - vsnet-newvar - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-newvar 9806] TCP J20002413+1959394: possible WZ Sge-type dwarf nova
by Naoto Kojiguchi 22 Feb '23

22 Feb '23

TCP J20002413+1959394: possible WZ Sge-type dwarf nova Large amplitude outburst of 7 mag. Possible WZ Sge-type dwarf nova. TCP J20002413+1959394 2023 02 20.8278* 20 00 24.13 +19 59 39.4 12.9 U Sge 9 0 http://www.cbat.eps.harvard.edu/unconf/followups/J20002413+1959394.html 2023 02 20.82785 Discovered by Hideo Nishimura, Kakegawa, Shizuoka, Japan on three frames (30-s exp. limiting mag 15) taken by Canon EOS 6D digital camera + 200-mm F/3.2 lens. On 2023 Feb. 19.81791 UT, mag=12.8 (limiting mag 15), 21.82700 UT, mag=13. Nothing is visible at this location on the frames taken on 2023 Feb. 17.83795 UT (limiting mag 15) by same instrument. --- Seiichiro Naito and Isao Endoh (NAOJ) IDs: 200024.105 +195939.939 Gaia_DR2_1823298696167827200 Plx=2.3425(0.9314) dismod=8.2 pmRA=-2.23(1.102) pmDE=-0.2(1.188) G=20.5707(0.0095) BP-RP=0.3392 E(g-r)=0.032 E(B-V)=0.028 Ag=0.113 Ar=0.084 Ai=0.063 200024.106 +195939.925 Gaia_EDR3_1823298696167827200 Plx=2.2632(0.7637) dismod=8.2 PM=1.398 pmRA=-1.07(0.729) pmDE=0.9(0.727) G=20.50371(0.008507) BP-RP=0.592648 E(g-r)=0.038 E(B-V)=0.034 Ag=0.134 Ar=0.100 Ai=0.075 200024.106 +195939.951 PS1_DR1_131993001004563865 g=20.9059(0.0725) r=20.6909(0.0366) i=20.6181(0.0451) z=20.1438(0.0897) y=19.9086(0.1157) 200024.103 +195940.056 PS1_DR2_131993001004563865 g=20.8611(0.017786) r=20.6897(0.016649) i=20.5832(0.022164) z=20.1729(0.033345) y=19.8057(0.052282) 200024.103 +195940.056 PS1_DR2_131993001004563865 g=20.8637(0.017634) r=20.6718(0.016989) i=20.564(0.022398) z=20.1733(0.034204) y=19.7821(0.051221) 200024.103 +195940.056 PS1_DR2_131993001004563865 g=20.872(0.017211) r=20.6751(0.016226) i=20.5458(0.0215) z=20.2063(0.034408) y=19.811(0.052392) ASAS-SN Sky Patrol: https://asas-sn.osu.edu/sky-patrol/coordinate/7badee06-5665-437e-9451-b5db4… ZTF alerts: https://alerce.online/object/ZTF23aacteoa MPChecker: NO DATA TCPJ20002413+1959394 20230217.83795 <150C (Hideo Nishimura) TCPJ20002413+1959394 20230219.555 14.037zr ZAD TCPJ20002413+1959394 20230219.555 14.038zr ZAL TCPJ20002413+1959394 20230219.81791 12.8C (Hideo Nishimura) TCPJ20002413+1959394 20230220.8278 12.9C (Hideo Nishimura) TCPJ20002413+1959394 20230221.553 13.905zr ZAL TCPJ20002413+1959394 20230221.553 14.211zr ZAD TCPJ20002413+1959394 20230221.555 13.918zr ZAL TCPJ20002413+1959394 20230221.555 14.290zr ZAD TCPJ20002413+1959394 20230221.558 13.864zr ZAL TCPJ20002413+1959394 20230221.558 14.237zr ZAD TCPJ20002413+1959394 20230221.560 13.860zr ZAL TCPJ20002413+1959394 20230221.560 13.995zr ZAD TCPJ20002413+1959394 20230221.82700 13.0C (Hideo Nishimura)

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[vsnet-newvar 9805] MASTER OT J055845.55+391533.4 outburst (likely AM CVn)
by Taichi Kato 22 Feb '23

22 Feb '23

MASTER OT J055845.55+391533.4 outburst (likely AM CVn) Maeda-san detected an outburst at 14.0 on Feb. 21. Supercycle 220-400 d (ZTF data).

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[vsnet-newvar 9804] Re: Spectrum of TCP J06442271+1549388
by Taichi Kato 21 Feb '23

21 Feb '23

Re: Spectrum of TCP J06442271+1549388 > We reported optical spectrum of TCP J17562787-1714 to ATel #15911 and > classify it as a He/N-type nova: V407 Cyg erupted in symbiotic environment and a fast nova. These features are not exclusive. Could be a nova similar to V407 Cyg?

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[vsnet-newvar 9803] TCP J17562787-1714548 (ATEL 15910)
by Taichi Kato 21 Feb '23

21 Feb '23

TCP J17562787-1714548 (ATEL 15910) > It is somewhat unusual for a nova to show shock-powered X-rays > visible to Swift/XRT less than two days after eruption. This may > suggest that the transient is a very fast nova and/or a nova > embedded in the wind of an evolved donor star. Possibly a nova that erupted in symbiotic environment. === ATEL #15910 ATEL #15910 Title: Swift/XRT detection of the nova candidate TCP J17562787-1714548 Author: Kirill Sokolovsky (UIUC), Kim Page (U. Leicester), Elias Aydi, Laura Chomiuk, Jay Strader (MSU), Jennifer Sokoloski (Columbia), Justin Linford (NRAO), Koji Mukai (NASA/GSFC) Queries: kirx(a)kirx.net Posted: 21 Feb 2023; 01:02 UT Subjects:Ultra-Violet, X-ray, Nova, Transient The candidate nova TCP J17562787-1714548 was discovered by Y. Sakurai, H. Nishimura, and A. Pearce using DSLR camera images with the first reported detection on 2022-02-18.834 UT at an unfiltered magnitude of 11. Follow-up astrometry by multiple observers reported via CBAT Transient Object Followup Reports page suggests Gaia DR3 4144602552564272000 (G=18.1, Plx=0.20+/-0.18 mas) as a possible progenitor that shows irregular variability in archival ZTF and ATLAS photometry (T. Kato, vsnet-alert 27432). Swift observed TCP J17562787-1714548 for 1.9ks on 2023-02-20.58. Swift/XRT detected an X-ray source with a net count rate of 0.043 +/-0.006 cts/s at the position of the transient. Most of the counts are above 3 keV, consistent with heavily absorbed (n_H > 10^23 cm^-2) thermal emission with kT > 1 keV. The Galactic absorbing column density in the direction of the source is n_H = 3.86x10^21 cm^-2 (Kalberla et al. 2005 A&A, 440, 775), suggesting the presence of source-intrinsic absorption. The XRT detection cannot be attributed to optical loading that should manifest itself as spurious soft (rather than hard) emission. Swift/UVOT detected a UVW1= 12.35 +/-0.02 (Vega system) ultraviolet source at the position of the transient. It is somewhat unusual for a nova to show shock-powered X-rays visible to Swift/XRT less than two days after eruption. This may suggest that the transient is a very fast nova and/or a nova embedded in the wind of an evolved donor star. We thank the Neil Gehrels Swift Observatory team and PI, Brad Cenko, for rapid execution this ToO observation. <a href="https://ztf.snad.space/dr13/view/332207100098232">ZTF photometry of the possible progenitor</a> CBAT Transient Object Followup Reports page: http://www.cbat.eps.harvard.edu/unc onf/followups/J17562787-1714548.html

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[vsnet-newvar 9802] CRTS J174033.4+414756 superoutburst continues
by Taichi Kato 21 Feb '23

21 Feb '23

CRTS J174033.4+414756 superoutburst continues YYYYMMDD(UT) mag observer 20230128.5155 19.929zr (ZTF Alert DC mag (Masci+ 2019)) 20230130.8567 <159c (Yutaka Maeda) 20230204.5406 14.241zr (ZTF Alert DC mag (Masci+ 2019)) 20230204.8568 123cG (Yutaka Maeda) 20230204.8568 123cG (Yutaka Maeda) 20230207.149 13.15CV (Klaus Wenzel) 20230207.160 131 (Klaus Wenzel) 20230209.137 132CV (Klaus Wenzel) 20230209.5379 14.331zg (ZTF Alert DC mag (Masci+ 2019)) 20230213.201 136CV (Klaus Wenzel) 20230214.8331 134cG (Yutaka Maeda) 20230215.8377 135cG (Yutaka Maeda) 20230220.196 141CV (Klaus Wenzel)

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[vsnet-newvar 9801] CSS J091017.4-200812: AM CVn-type superoutburst
by Taichi Kato 21 Feb '23

21 Feb '23

CSS J091017.4-200812: AM CVn-type superoutburst Berto Monard has reported observations. Based on a single-night run, superhumps with a period of 0.0205(1) d and amplitude of 0.07 mag were detected.

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[vsnet-newvar 9800] Re: MGAB-V240: standstill interrupted by fading (AM CVn?)
by Taichi Kato 20 Feb '23

20 Feb '23

Re: MGAB-V240: standstill interrupted by fading (AM CVn?) > If this identification is correct, repeated regular > outbursts before 2020 were superoutbursts (with a supercycle > of about 10-15 d). Faint, but unusual object. I indeed detected superhumps during one of its outburst in 2018 June-July (time-resolved ZTF data on two nights). The period was 0.015822(9) d and an amplitude of 0.09 mag. This object is probably between dwarf nova-type CR Boo (Porb=0.017029 d) and novalike HP Lib (Porb=0.012763 d).

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[vsnet-newvar 9799] MGAB-V240: standstill interrupted by fading (AM CVn?)
by Taichi Kato 20 Feb '23

20 Feb '23

MGAB-V240: standstill interrupted by fading (AM CVn?) Using ZTF data in 2022, I noticed that a standstill was interrupted by up to 2 mag short fading at least four times. The object became brighter (for a short time) after such events. The fading rates exceeded 1 mag/d in some cases and this object may be an AM CVn star. If this identification is correct, repeated regular outbursts before 2020 were superoutbursts (with a supercycle of about 10-15 d). Faint, but unusual object.

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[vsnet-newvar 9798] MGAB-V300 outburst (suspected AM CVn)
by Taichi Kato 20 Feb '23

20 Feb '23

MGAB-V300 outburst (suspected AM CVn) YYYYMMDD(UT) mag observer 20230218.5603 15.430zr (ZTF Alert DC mag (Masci+ 2019)) 20230218.5627 15.369zr (ZTF Alert DC mag (Masci+ 2019)) 20230218.5652 15.425zr (ZTF Alert DC mag (Masci+ 2019))

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[vsnet-newvar 9797] TCP J17562787-1714548
by Taichi Kato 20 Feb '23

20 Feb '23

TCP J17562787-1714548 http://cbat.eps.harvard.edu/unconf/followups/J17562787-1714548.html The quiescent counterpart 2MASS 175627.896 -171453.26 (2000.0) 15.474 13.516 13.211 175627.901 -171453.72 (2000.0) Gaia_DR2_4144602552564272000 plx=0.198(0.244) dismod=13.5 pmra=0.263(0.373) pmdec=-7.070(0.330) G=18.124 BP=18.710 RP=17.038 175627.901 -171453.73 (2000.0) Gaia_EDR3_4144602552564272000 plx=0.202(0.187) dismod=13.5 pmra=0.851(0.177) pmdec=-6.670(0.121) G=18.119 BP=18.871 RP=17.093 was relatively variable both in ZTF and ATLAS. Nova containing a giant? (such as a symbiotic one)

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vsnet-newvar February 2023