ASASSN-19wu: new transient (14.3 mag) in Scorpius

Affiliation
Association Francaise des Observateurs d'Etoiles Variables (AFOEV)
Wed, 09/18/2019 - 07:16

ASASSN-19wu (N:/UG:)
https://www.aavso.org/vsx/index.php?view=detail.top&oid=945689

Nova or CV near the galactic plane, rapid rise, matches to PS1 g=17.8,
g>16.8 on 2019-09-15.85, g=17.2 on 2019-09-16.11, g=15.7 on 2019-09-17.10, g=14.3 on 2019-09-17.79.
http://www.astronomy.ohio-state.edu/~assassin/transients.html

ASASSN-19wu 20190915.85 <168g ASN
ASASSN-19wu 20190916.11 172g ASN
ASASSN-19wu 20190917.10 157g ASN
ASASSN-19wu 20190917.79 143g ASN

For a dwarf nova with a short orbital period this would be a relatively slow rise, so this transient may be a nova eruption or an SS Cyg-type dwarf nova outburst.

No previous eruptions or outbursts were recorded since 2016 March 10 in ASAS-SN Sky Patrol data (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017 PASP..129j4502K):
https://asas-sn.osu.edu/light_curves/f962a5ee-7413-4425-9a59-0b54b67c3d…

Precise astrometry, spectroscopy, and multiband (also time-resolved) photometry are urgently required.

Clear skies,
Patrick

Affiliation
American Association of Variable Star Observers (AAVSO)
ASASSN-19wu

Hello all!

2019 Sep. 18.43852 <10.3 TG

Canon EOS 60D, 135 mm, f/5.6, 30 sec., ISO-2000.
Yuzhno-Morskoy (near Nakhodka, Russia).

Affiliation
Association Francaise des Observateurs d'Etoiles Variables (AFOEV)
Re: ASASSN-19wu Snapshot

Hi Erik,

Thanks a lot for your response.
Yes, these FITS files would be very helpful. What is the magnitude limit?
CCD images are mainly needed for precise astrometry of the transient.

Patrick (Schmeer)

Affiliation
American Association of Variable Star Observers (AAVSO)
ASASSN-19wu Snapshot

Hi Patrick,

It looks like limiting magnitude of each 60 second exposure is around magnitude 17 (S/N 6).

CCD FOV 22.5'X16.9'      0.7"/pixel

altitude approx 20 degrees

Erik