[vsnet-alert 25785] Re: ASASSN-21gk: strange light curve

[Patrick Schmeer pasc1312-aavso@yahoo.de via vsnet-alert]

 ASASSN-21gk
https://www.aavso.org/vsx/index.php?view=detail.top&oid=2217877
 
Taichi Kato wrote (see his message below):
> Spectroscopy is needed.

I had asked already on April 23 (in vsnet-alert 25757 etc.) for spectroscopy, see e.g.
http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/25757 
Any results so far?

Recent ASAS-SN Sky Patrol light curve and data: 
https://asas-sn.osu.edu/sky-patrol/coordinate/20e86aaf-ddb7-48b5-9804-9379532861ba

Btw, due to sparse coverage the ZTF light curve in not so spectacular:
https://lasair.roe.ac.uk/object/ZTF19abfleei/
 
Siegfried Vanaverbeke wrote:
> The AAVSO lightcurve is pretty spectacular!

AAVSO observations still come from only *one* observer (Josch Hambsch, HMB):
https://app.aavso.org/webobs/results/?star=ASASSN-21gk
 
Hopefully more observations will be reported, when the Moon is farther away
from this target (currently only about 13°).
 
Clear skies,
Patrick
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References:
All-Sky Automated Survey for Supernovae (ASAS-SN) Sky Patrol:
- Shappee et al., 2014ApJ...788...48S
- Kochanek et al., 2017PASP..129j4502K
Lasair:
- Smith et al., 2019RNAAS...3...26S
Zwicky Transient Facility (ZTF):
- Masci et al., 2019PASP..131a8003M
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     Am Samstag, 1. Mai 2021, 09:54:04 MESZ hat Siegfried Vanaverbeke siegfriedvanaverbeke at gmail.com via vsnet-alert <vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp> Folgendes geschrieben:  
 
 The AAVSO lightcurve is pretty spectacular !

Op za 1 mei 2021 om 09:51 schreef Siegfried Vanaverbeke <
siegfriedvanaverbeke at gmail.com>:

> Indeed it doesn't appear consistent with microlensing from your
> description of the lightcurve.
>
> Siegfried
>
> Op za 1 mei 2021 om 02:58 schreef Taichi Kato <
> tkato at kusastro.kyoto-u.ac.jp>:
>
>> ASASSN-21gk: strange light curve
>>
>>    Josch Hambsch has reported observatioons.
>> This object (microlensing?) has shown a very unusual
>> light curve.  Rapid rise on Apr. 22, around maximum
>> on Apr. 25, faint on Apr. 27, rapid fade on Apr. 29,
>> rapid rise on Apr. 30.  Such a variation would not
>> expected for a simple microlensing.
>> Spectroscopy is needed.
>>
>>