- vsnet-campaign-symbio - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-campaign-symbio 212]NSV21190: eclipsing symbiotic star currently undergoing symbiotic nova outburst?
by Taichi Kato 07 Jul '23

07 Jul '23

NSV21190: eclipsing symbiotic star currently undergoing symbiotic nova outburst? Yamamoto had reported brightening of this object in April. YYYYMMDD(UT) mag observer 20230422.744 132c (Minoru Yamamoto) Tadashi Kojima-san has reported that the object has been bright for months. object YYYYMMDD(UT) mag code NSV21190 20230331.758 128c Tko.VSOLJ NSV21190 20230517.629 128c Tko.VSOLJ NSV21190 20230617.503 128c Tko.VSOLJ NSV21190 20230706.553 127c Tko.VSOLJ This object has been suggested to be a large-amplitude variable star TerzV910 (suspected to be a Mira star based on IRAS identification). ASAS-SN data https://asas-sn.osu.edu/sky-patrol/coordinate/d5a29922-5bc0-4e1e-824e-086ac… and ATLAS observations suggest that this object appears to be an eclipsing symbiotic object, rather than a Mira star, which became active (at least) in in 2017. The minima occurred JD 2458240:, 2458660, 2459060: (P about 410 d?). The object once became faint in later 2020-later 2021, and then brightened to the current bright state. A shallow minimum around JD 2459830 during the present bright state may be an eclipse (the period then is around 400 d). The object was faint during ASAS-3 observations (2000-2009). The object is currently slowly brightening and would be another symbiotic nova (the shallow eclipse may be explained by a nova photosphere). The position is somewhat different between 2MASS and Gaia: 2MASS 171453.440 -283746.69 (2000.0) 15.129 12.170 9.707 171453.437 -283746.95 (2000.0) Gaia_DR2_4107611274955676672 plx=-(-) dismod=- pmra=-(-) pmdec=-(-) G=19.526 BP=20.104 RP=17.634 171453.437 -283746.96 (2000.0) Gaia_EDR3_4107611274955676672 plx=2.187(0.418) dismod=8.3 pmra=-6.604(0.411) pmdec=-7.609(0.337) G=19.598 BP=20.516 RP=18.301 I used the 2MASS location.

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[vsnet-campaign-symbio 211]V2756 Sgr fading
by Taichi Kato 15 Nov '22

15 Nov '22

V2756 Sgr fading Eclipse? Fading more than 1 mag in early 2003 in ASAS-3 data. Gaia22eor AT2022aagn 2022-10-26 10:49:19 273.64382 -29.82333 13.17 12.07 0.16 symbiotic star 2022-11-14 10:57:08 known Symbiotic star fades by 1 mag http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia22eor/

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[vsnet-campaign-symbio 210]Re: V618 Sgr fading
by Taichi Kato 14 Jul '22

14 Jul '22

Re: V618 Sgr fading This looks like an eclipse. There were deep (more than 3 mag) fading events in 2018 Aug.-Oct. and 2020 July-Oct. A period of 710 d has been inferred. This symbiotic variable is faint at minimum and eclipses may be prominent only during outbursts when the disk becomes bright. Multicolor photometry of this eclipse may be helpful in understanding the structure of the disk.

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