- vsnet-rcb - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-rcb 885] V854 Cen Below Maximum Brightness
by Peter Williams 11 Oct '23

11 Oct '23

The southern RCB star V854 Cen has again faded to about 1 magnitude below its usual maximum brightness and, based on its history of being one of the more active RCB stars, would seem to be overdue for a deep decline. The last deep but brief decline commenced in 2022 July. V854 Cen is, however, now becoming difficult to observe as it approaches conjunction with the sun. Recent visual observations : CENV854 20230915.437 73 WPX CENV854 20230918.411 74 WPX CENV854 20231008.416 79 WPX CENV854 20231009.426 81 WPX CENV854 20231011.388 82 WPX Tks and regards Peter Williams Heathcote NSW 10x50mm & 20x80mm binoculars

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[vsnet-rcb 884] AO Her in 2021 and anomaly in visual observations
by Taichi Kato 20 Jul '23

20 Jul '23

AO Her in 2021 and anomaly in visual observations Prompted by BAA VSS Circular No. 196, I checked the past light curve of the R CrB star AO Her. The observations by two most prominent visual observers around the 2021 fading did not agree at all with CCD observations. They (and also Jose Ripero, as I suggested in vsnet-alert regarding other objects) didn't notice the start of the July-Aug. fading for more than two weeks. They reported unreal fading in Apr.-June. They also didn't notice the brightening in the later half of 2020. The reported values, however, agreed very well between these observers (but no correlation with CCD observations). A naive interpretation of this strange phenomenon would be that these observers were copying other persons' observations each other. They were not correlated with actual variations and researchers should pay attention when using any database (e.g. AAVSO) containing observations of these observers. Of course, I had noticed the sign from the past (already in 1996 in V705 Cas, which was interpreted as a "telephone effect" by Gary Poyner if I remember correctly), but the present case and other cases are too apparent with sufficient evidence in the presence of modern CCD data.

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[vsnet-rcb 883] Re: NSV21190: eclipsing symbiotic star currently undergoing symbiotic nova outburst?
by Taichi Kato 09 Jul '23

09 Jul '23

Re: NSV21190: eclipsing symbiotic star currently undergoing symbiotic nova outburst? The object turned out to be an R CrB star. https://www.aavso.org/vsx/index.php?view=detail.top&oid=59625 https://ui.adsabs.harvard.edu/abs/2020A%26A...635A..14T/abstract Relatively periodic behavior in 2017-2020 would suggest the pulsation origin like DY Per stars.

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[vsnet-rcb 882] ES Aql fading
by Taichi Kato 20 Jun '23

20 Jun '23

ES Aql fading YYYYMMDD(UT) mag observer 20230307.8541 117:cG (Yutaka Maeda) 20230421.7890 119cG (Yutaka Maeda) 20230430.6832 120cG (Yutaka Maeda) 20230515.6804 121cG (Yutaka Maeda) 20230523.6556 123cG (Yutaka Maeda) 20230619.5552 13.25V (Minoru Sato)

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[vsnet-rcb 881] Re: [VSS] RCB Star IO Nor is undergoing a decline & [VSS] RCB star V653 Sco is undergoing a decline
by Peter Williams 05 Jun '23

05 Jun '23

Hi Andrew, Great to see someone keeping a regular watch on these southern RCB stars! CC to the vsnet-rcb and vsnet-alert groups for info, but I cannot remember if they accept the light curve attachments :) Tks and regards Peter Williams Heathcote NSW From: variablestarssouth(a)googlegroups.com [mailto:variablestarssouth@googlegroups.com] On Behalf Of Andrew Pearce Sent: Monday, 5 June 2023 11:15 AM To: Variable Stars South <VariableStarsSouth(a)googlegroups.com> Subject: [VSS] RCB Star IO Nor is undergoing a decline Hi All Another little observed RCB star, IO Nor, is undergoing a decline as per the attached light curve. Regards Andrew = = = = = = = = = = = = = = = = = = = = From: variablestarssouth(a)googlegroups.com [mailto:variablestarssouth@googlegroups.com] On Behalf Of Andrew Pearce Sent: Monday, 5 June 2023 10:45 AM To: Variable Stars South <VariableStarsSouth(a)googlegroups.com> Subject: [VSS] RCB star V653 Sco is undergoing a decline Hi All The little observed RCB star, V653 Sco, is undergoing a decline as can be seen from the attached light curve. Years ago, professional astronomers used to be very interested in RCB fades. That doesn't seem to be the case anymore at least that I'm aware of. Regards Andrew = = = = = = = = = = = = = = = = = = = = -- You received this message because you are subscribed to the Google Groups "Variable Stars South" group. To unsubscribe from this group and stop receiving emails from it, send an email to VariableStarsSouth+unsubscribe(a)googlegroups.com <mailto:VariableStarsSouth+unsubscribe@googlegroups.com> . To view this discussion on the web, visit https://groups.google.com/d/msgid/VariableStarsSouth/e7b14d23-70f2-4b8d-96f… <https://groups.google.com/d/msgid/VariableStarsSouth/e7b14d23-70f2-4b8d-96f…> .

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[vsnet-rcb 880] R CrB fading?
by Taichi Kato 02 Jun '23

02 Jun '23

R CrB fading? Several observers have pointed out that R CrB may be getting fainter. YYYYMMDD(UT) mag observer 20230518.9063 60 (Eddy Muyllaert) 20230519.744 61 (Susumu Takahashi) 20230520.542 60 (Susumu Takahashi) 20230520.567 61 (Yoshiyasu Sato) 20230521.008 60 (Gary Poyner) 20230521.985 59 (Gary Poyner) 20230523.001 59 (Gary Poyner) 20230523.544 60 (Hiroyuki Maehara) 20230523.565 64 (Kenji Nakai) 20230523.606 61 (Yoshiyasu Sato) 20230524.019 60 (Gary Poyner) 20230524.485 63 (Tsuneo Horie) 20230524.508 61 (Masashi Nakatani) 20230524.585 61 (Yoshiyasu Sato) 20230524.944 60 (Gary Poyner) 20230525.510 60 (Hiroyuki Maehara) 20230525.581 61 (Yoshiyasu Sato) 20230526.990 60 (Gary Poyner) 20230527.442 65 (Tsuneo Horie) 20230527.978 62 (Gary Poyner) 20230528.965 64 (Gary Poyner) 20230529.8785 62 (Jose Ripero) 20230529.951 64 (Gary Poyner) 20230530.492 61 (Yoshiyasu Sato) 20230531.535 62 (Yoshiyasu Sato) 20230531.597 64 (Masashi Nakatani) 20230531.867 66 (Klaus Wenzel)

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[vsnet-rcb 875] V854 Cen Possible Decline Onset
by Peter Williams 27 May '23

27 May '23

Good morning, The bright southern RCB star V854 Cen has shown a gradual fading over the past 2 weeks, suggesting the possible onset of a deep decline may have commenced. This star was at visual magnitude 8.0 last night (May 18), a half magnitude below its normal maximum brightness. Typically, if it fades to magnitude 8.5 it will continue onto a deep decline. Observations over the next few days will confirm if this does indeed occur. The previous deep decline commenced in July 2022. Recent visual observations of V854 Cen: CEN V854 20230427.428 75 WPX CENV854 20230501.397 74 WPX CENV854 20230504.422 74 WPX CENV854 20230510.393 76 WPX CENV854 20230512.381 76 WPX CENV854 20230516.364 79 WPX CENV854 20230518.448 80 WPX Tks & regards Peter Williams Heathcote NSW 10x50mm binoculars

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[vsnet-rcb 877] Gaia DR3 5931782154434729600 = Gaia23bt: likely RCB star fading
by Taichi Kato 21 May '23

21 May '23

Gaia DR3 5931782154434729600 = Gaia23bt: likely RCB star fading http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia23btd/ Non-red and luminious object. Consistent with RCB. 2MASS 161615.906 -544445.35 (2000.0) 12.495 12.134 11.774 161615.9 -544445 (2000.0) Gaia_DR3_5931782154434729600 RS (score=0.01) 161615.931 -544445.47 (2000.0) Gaia_DR2_5931782154434729600 plx=0.015(0.032) dismod=19.2 pmra=-2.920(0.052) pmdec=-2.724(0.041) G=14.549 BP=15.236 RP=13.707 161615.930 -544445.47 (2000.0) Gaia_EDR3_5931782154434729600 plx=0.021(0.024) dismod=18.4 pmra=-2.885(0.028) pmdec=-2.745(0.021) G=14.538 BP=15.214 RP=13.699

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[vsnet-rcb 874] SU Tau started fading?
by Taichi Kato 02 Apr '23

02 Apr '23

SU Tau started fading? Sato-san has pointed out the gradual fading. YYYYMMDD(UT) mag observer 20230318.8813 100 (Eddy Muyllaert) 20230319.439 105 (Takuichiro Onishi) 20230319.4497 10.13V (Minoru Sato) 20230319.549 101 (Yoshiyasu Sato) 20230319.8153 99 (Jose Ripero) 20230320.4490 10.18V (Minoru Sato) 20230321.8132 101 (Eddy Muyllaert) 20230325.4272 10.35V (Minoru Sato) 20230326.5031 103cG (Yutaka Maeda) 20230326.5736 104V (Masayuki Moriyama) 20230327.4096 10.52V (Minoru Sato) 20230327.8340 100 (Eddy Muyllaert) 20230328.4183 10.55V (Minoru Sato) 20230328.5680 105V (Masayuki Moriyama) 20230329.4157 10.59V (Minoru Sato) 20230329.8438 100 (Eddy Muyllaert) 20230330.4337 10.66V (Minoru Sato) 20230330.451 104 (Tsuneo Horie) 20230331.437 104 (Tsuneo Horie) 20230331.465 107 (Hiroyuki Maehara) 20230331.5062 106cG (Yutaka Maeda) 20230331.5983 107V (Masayuki Moriyama) 20230401.542 111 (Takuichiro Onishi)

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[vsnet-rcb 873] RY Sgr fading again
by Taichi Kato 18 Nov '22

18 Nov '22

RY Sgr fading again YYYYMMDD(UT) mag observer 20221106.394 120 (Takuichiro Onishi) 20221107.392 <121 (Takuichiro Onishi) 20221107.4139 12.11V (Masayuki Moriyama) 20221109.392 <121 (Takuichiro Onishi) 20221109.4138 12.07V (Masayuki Moriyama) 20221110.408 12.02V (Hiroshi Itoh) 20221111.394 <121 (Takuichiro Onishi) 20221112.396 125: (Takuichiro Onishi) 20221116.4048 13.27V (Masayuki Moriyama)

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