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[vsnet-chat 9320] VSOLJ Variable star bulletin No.111
by meineko 23 Feb '23

23 Feb '23

VSOLJ Variable star bulletin No.111 is now available at http://vsolj.cetus-net.org/bulletin.html No.111 2023 Feb. MGAB-V240: 23-min AM CVn star showing both 12-d supercycle and standstills Taichi Kato Seiichiro Kiyota VSOLJ

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[vsnet-chat 9319] VSOLJ Variable Star Bulletin No.109 and No.110
by meineko 20 Feb '23

20 Feb '23

Following isues of VSOLJ Variable Star Bulletin are available at http://vsolj.cetus-net.org/bulletin.html No.109 2023 Feb. ASASSN-15cm: an SU UMa star with an orbital period of 5.0 hours Taichi Kato No.110 2023 Feb. On the orbital period of the dwarf nova CW Mon Taichi Kato and Franz-Josef Hambsch Seiichiro Kiyota VSOLJ

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[vsnet-chat 9318] 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-chat 9317] 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-chat 9316] SSS J090619.2-275831: ER UMa star
by Taichi Kato 16 Feb '23

16 Feb '23

SSS J090619.2-275831: ER UMa star Using ATLAS forced photometry (Tonry et al. 2018; Shingles et al. 2021). Almost certainly ER UMa star, regular supercycle of 50-55 d. Maximum 16.0 mag.

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[vsnet-chat 9315] SDSSp J083845.23+491055.5 stopped outbursting
by Taichi Kato 16 Feb '23

16 Feb '23

SDSSp J083845.23+491055.5 stopped outbursting No outburst has been recorded since 2014 (ZTF data since 2018). Relatively regular outbursts up to 2013.

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[vsnet-chat 9314] SDSS J231226.62+544804.4: IW And star
by Taichi Kato 16 Feb '23

16 Feb '23

SDSS J231226.62+544804.4: IW And star Very clear in ZTF data. Deep minimum reached g=18.5.

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[vsnet-chat 9313] ASASSN-15cm: SU UMa star with Porb=0.2085 d
by Taichi Kato 11 Feb '23

11 Feb '23

ASASSN-15cm: SU UMa star with Porb=0.2085 d Using ZTF (Masci et al., 2019) and ATLAS forced photometry (Tonry et al. 2018; Shingles et al. 2021) data, I found that this object showed a superoutburst in 2019 Aug. Like BO Cet with the same set of data (arXiv:2302.02593 = VSOLJ Variable Star Bulletin No. 106), I obtained a period of 0.2196(1) d, 5.3% longer than the orbital period. This corresponds to q about 0.22 (arXiv:2201.02945 = VSOLJ Variable Star Bulletin No. 89). The core of the secondary of this object appears to be evolved (Thorstensen et al. 2016 AJ 152, 226) and this probably enabled a relatively small q. Another apparent superoutburst was also recorded in 2022 Jan. and future direct detection of superhumps are wanted.

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[vsnet-chat 9312] VSOLJ Variable Star Bulletin No.107 and No.108
by meineko 10 Feb '23

10 Feb '23

Following new issues of VSOLJ Variable Star Bulletin are now available at http://vsolj.cetus-net.org/bulletin.html No.107 2023 Feb. PDF Genuine standstill in the AM CVn star CR Boo Taichi Kato, Yutaka Maeda, Masayuki Moriyama No.108 2023 Feb. PDF Visual,CCD and DSLR minima of eclipsing binaries during 2022 Kazuo Nagai Seiichiro Kiyota VSOLJ

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[vsnet-chat 9311] ASASSN-V J003612.92-464406.4: polar
by Taichi Kato 10 Feb '23

10 Feb '23

ASASSN-V J003612.92-464406.4: polar Using ATLAS forced photometry (Tonry et al. 2018; Shingles et al. 2021). Porb=0.0918846(1) d. 1.4-mag orbital variation. High and low states.

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