March 2022 - vsnet-newvar - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-newvar 9121] ASASSN-21ls: dwarf nova below the period gap with strong reflection effect
by Taichi Kato 18 Mar '22

18 Mar '22

ASASSN-21ls: dwarf nova below the period gap with strong reflection effect From ZTF data. Porb = 0.0579261(1) d. The orbital profile looks like a detached subdwarf binary. There was indication of primary eclipse (but not sharp, probably due to the accretion disk). Total amplitude 0.58 mag. Too red for this Porb and the secondary may be evolved. Long outburst in 2021 June-July with rebrightenings. The overall type is UGSU:+R+E

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[vsnet-newvar 9120] ASASSN-21dh: object below the period gap
by Taichi Kato 18 Mar '22

18 Mar '22

ASASSN-21dh: object below the period gap From ZTF data. I obtained a period of 0.0943185(3) d. Double-wave modulation (amplitude 0.25 mag). The color is red for this period and the secondary may be somewhat evolved.

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[vsnet-newvar 9119] ASASSN-21ap: likely helium dwarf nova (superoutburst in 2021 Feb)
by Taichi Kato 18 Mar '22

18 Mar '22

ASASSN-21ap: likely helium dwarf nova (superoutburst in 2021 Feb) From ZTF data. Short initial outburst, rapid fading and rebrightening. Short rebrightening on a fading tail. All characteristic to an AM CVn-type superoutburst.

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[vsnet-newvar 9118] ASASSN-15am: SS Cyg outbursts from a long-Porb binary
by Taichi Kato 18 Mar '22

18 Mar '22

ASASSN-15am: SS Cyg outbursts from a long-Porb binary Using the ZTF data, I obtained a period of 0.687879(3) d. This period was based on slight differences between maxima and minima within one cycle. Half a period (0.343939 d) gives a reasonable phased light curve but is not sinusoidal and I consider that the original period is correct. The amplitude is 0.27 mag. Outbursts were present both in ASAS-SN and ZTF data. The M_V of the outbursts (+6) is somewhat fainter than those of typical dwarf nova outbursts.

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[vsnet-newvar 9117] ASASSN-15rs superoutburst
by Taichi Kato 18 Mar '22

18 Mar '22

ASASSN-15rs superoutburst YYYYMMDD(UT) mag observer 20220307.5176 <160c (Yutaka Maeda) 20220308.492 175C (Mitsutaka Hiraga) 20220308.5174 <163c (Yutaka Maeda) 20220309.5193 <153c (Yutaka Maeda) 20220310.5125 <145c (Yutaka Maeda) 20220312.4952 142:cG (Yutaka Maeda) 20220315.5073 <133c (Yutaka Maeda) 20220315.5319 146C (Masayuki Moriyama) 20220316.5009 143cG (Yutaka Maeda) 20220316.5009 143cG (Yutaka Maeda)

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[vsnet-newvar 9116] MASTER OT J021216.01+461154.5 possible superoutburst
by Taichi Kato 18 Mar '22

18 Mar '22

MASTER OT J021216.01+461154.5 possible superoutburst Type from ZTF data. Supercycle about 800 d. YYYYMMDD(UT) mag observer 20220306.4731 <153c (Yutaka Maeda) 20220307.469 <174C (Mitsutaka Hiraga) 20220307.4768 <150c (Yutaka Maeda) 20220308.465 <174C (Mitsutaka Hiraga) 20220308.4765 <155c (Yutaka Maeda) 20220309.4784 <152c (Yutaka Maeda) 20220311.4562 <155c (Yutaka Maeda) 20220312.4537 <154c (Yutaka Maeda) 20220315.4640 139cG (Yutaka Maeda) 20220316.4602 138cG (Yutaka Maeda) 20220316.5197 140:C (Masayuki Moriyama)

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[vsnet-newvar 9115] Re: ASASSN-22dl: new WZ Sge-type dwarf nova with large-amplitude early superhumps
by Taichi Kato 17 Mar '22

17 Mar '22

Re: ASASSN-22dl: new WZ Sge-type dwarf nova with large-amplitude early superhumps Using the ZTF data, I obtained Min(BJD) = 2458713.27415(12) + 0.05561039(3) d This is a deeply eclipsing WZ Sge-type object whose eclipse minima were below the detection limit of the ZTF observations. Orbital humps before the eclipses were also apparent, suggesting that the mass-transfer rate is not very low. The period of early superhumps (but still from a short baseline) is shorter than the orbital period by 0.13%, typical for a WZ Sge star. Tampo-san and Sebastian, please be careful about in drawing the conclusion. The ZTF data also have one-day aliases.

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[vsnet-newvar 9114] Re: ASASSN-22dl: new WZ Sge-type dwarf nova with large-amplitude early superhumps
by Taichi Kato 17 Mar '22

17 Mar '22

Re: ASASSN-22dl: new WZ Sge-type dwarf nova with large-amplitude early superhumps I obtained a period of 0.0561(3) d from Kyoto U. data alone (very good data). The combined set with Itoh-san's data yielded a period of 0.05554(2) d. It looks like that the longer period is the true one.

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[vsnet-newvar 9113] ASASSN-22dl: superhump or early superhump?
by Taichi Kato 15 Mar '22

15 Mar '22

ASASSN-22dl: superhump or early superhump? Itoh-san detected large variations up to 0.8 mag. There were two maxima in one cycle and the profile suggest either an early superhump or superhump + eclipse. The period was around 0.054 d. Further observations are encouraged.

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[vsnet-newvar 9101] ASASSN-19hd rare outburst
by Taichi Kato 15 Mar '22

15 Mar '22

ASASSN-19hd rare outburst SU UMa star? YYYYMMDD(UT) mag observer 20220305.5545 <170c (Yutaka Maeda) 20220306.5578 <154c (Yutaka Maeda) 20220307.5619 <165c (Yutaka Maeda) 20220308.5617 <162c (Yutaka Maeda) 20220309.5636 <160c (Yutaka Maeda) 20220310.5563 146:c (Yutaka Maeda)

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