AAVSO: American Association of Variable Star Observers

Proposal #136

Proposer (3522) Bart Staels (STAELS.BART.BVBA@PANDORA.BE) obscode: SBL
Assigned To(3663) Dirk Terrell
Date SubmittedMarch 15, 2020

Urgent request to monitor this new transient in multiple wavelengths with OC61:ASASSN-20da: new transient (12.0 mag) in Circinus
RA 14:50:06.70, DE -65:49:46.9 (J2000.0)
bright transient near the Galactic plane, very unusual light curve,
matches to Gaia DR2 5848963158970287616 (G=12.3), ...

Complete ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S
and Kochanek et al. 2017PASP..129j4502K) light curve and data:

Almost constant (Vmag. 12.4) in ASAS-3.
Gaia DR2 parallax 1.5565 ± 0.0299 mas (distance 631 ± 12 pc). Common proper motion pair with Gaia DR2 5848962403056043136 (Gmag. 15.0, parallax 1.5999 ± 0.1146 mas, distance 619 ± 48 pc), which is 1.8" to the SSW.

It is unclear which of the two components has brightened. Spectroscopy and precise astrometry are urgently required (multiband as well as time-resolved photometry are encouraged, too).

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
ASASSN-20da 14.835194 -65.82969 12.0–11.5 OC61 Daily Sept. 21, 2020 6 Months


(4726) Kenneth Menzies — March 17, 2020, 10:45 a.m.


It would be helpful for you to propose a specific plan (filters/frequency) rather than restate the ambiguous "(multiband as well as time-resolved photometry are encouraged, too)"?


(3663) Dirk Terrell — March 19, 2020, 4:34 p.m.

The TAC recommends multiple filters. At that brightness, BVRI should work well.

(4848) George Silvis — March 25, 2020, 10:42 a.m.

This is a test comment.
Changes have been made so that all comments will be broadcast to the tac@aavso.org group. This is to encourage all receivers to come back to this page and answer via comments instead of emails, thus giving us a better record of the discussion.

(4726) Kenneth Menzies — March 25, 2020, 11:16 a.m.

Committed to OC61. 3 sets of images in BVSRSI.
Bart: See how this works?

(3522) Bart Staels — March 25, 2020, 11:34 a.m.

OK Kenneth, I'll let you know when the first images arrive. Thanks.

Comments on this proposal are closed.