ASASSN-21lk: new transient (mag. 14.4) in Scorpius

SPK
Affiliation
Association Française des Observateurs d'Étoiles Variables (AFOEV)
Tue, 06/22/2021 - 17:30

ASASSN-21lk  (N:/UG:)
https://www.aavso.org/vsx/index.php?view=detail.top&oid=2223219

Recent ASAS-SN Sky Patrol light curve and data:
https://asas-sn.osu.edu/sky-patrol/coordinate/33539ced-d7ca-4dc1-9f7b-b8c6d09da334

No previous brightening in ASAS-SN Sky Patrol or ATLAS data.

Spectroscopy, precise astrometry and multiband photometry (V, B, ...) are required.

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
Asteroid Terrestrial-impact Last Alert System (ATLAS):
- Tonry et al., 2018PASP..130f4505T

CTX
Affiliation
American Association of Variable Star Observers (AAVSO)
ASASSNi21lk Sequence

ASASSNi21lk Sequence is now available...

tough fov with close doubles and many red stars + some

of the faint ones are distant from Target... it is what it is.

Tim Crawford, sequence Team

 

FRF
Affiliation
Magyar Csillagàszati Egyesület, Valtózocsillag Szakcsoport (Hungary) (MCSE)
Brightening: now aroung 13.0TG

I managed to catch ASASSN-21lk with a 135mm Samyang telephoto lens - remotely from Chile.
It was was around 13.0TG on June 23.2334UT and 11.6TR on June 23.2350UT. Reddish color. Probably a galactic nova.

Images:
https://twitter.com/fidusz/status/1407588671000387584

FRF
Affiliation
Magyar Csillagàszati Egyesület, Valtózocsillag Szakcsoport (Hungary) (MCSE)
RGB color image of ASASSN-21lk

RGB color image of ASASSN-21lk (2-2x30s with red, green and blue filters):
https://twitter.com/fidusz/status/1407627129425125381

Clear skies,

Robert

FRF
Affiliation
Magyar Csillagàszati Egyesület, Valtózocsillag Szakcsoport (Hungary) (MCSE)
13.035 TG on June 23.2340 UT

Proper ensemble photometry of the two CCD images with green filter (based on APASS DR9 comp stars):

ASASSN-21lk 20210623.2340 UT 13.035 TG (0.016)
ASASSN-21lk 20210623.2356 UT 11.649TR (0.089)

CTX
Affiliation
American Association of Variable Star Observers (AAVSO)
Brighter Comps Now Added

Brighter Comps down to ~10.9V are now available

Tim Crawford, Sequence Team

FRF
Affiliation
Magyar Csillagàszati Egyesület, Valtózocsillag Szakcsoport (Hungary) (MCSE)
B-V=1.4 mag

BVI observations of Josh Hambsch confirm, that this is a red variable with B-V=1.4 color index:
https://app.aavso.org/webobs/results/?star=000-BNZ-929&num_results=200

However Timothy Weaver (WTIC) might have mixed V and I filters with I and R, respectively, thus he's got negative (blue) color index. The DSLR photos of Rob Kaufman, Australa also confirms, this is a red variable:
http://vendegcsillagkereso.blogspot.com/2021/06/novavadaszat-telehold-idejen-asassn.html