Magellanic Cloud Photometric Survey (MCPS) Constraints on the Progenitor of Possible LMC Nova ASASSN-18pf
ATel #11863; Peter Pessev (GRANTECAN, IAC, ULL), Dennis Zaritsky (Steward Observatory, UA)
on 17 Jul 2018; 08:03 UT
Credential Certification: Peter Pessev (peter.pessev@gtc.iac.es)
Subjects: Optical, Nova, Transient
I report constraints on the possible progenitor of the LMC Nova ASASSN-18pf, based on Magellanic Cloud Photometric Survey (MCPS; Zaritsky et al. 1997) archival data. There is a counterpart source located at coordinates:
R.A.=85.44513 deg. and Dec.=-71.80994 deg.
or 2.5 arc seconds away from the reported ASAS-SN position:
R.A.=05:41:46.461; Dec.=-71:48:37.59.
Taking into account the pixel scale of the ASAS-SN cameras (8"/pixel), both sources are identical within the positional uncertainty. The source has the following magnitudes:
B=21.537+/-0.119;
V=21.105+/-0.096;
I=20.806+/-0.216.
The extinction in the direction of the transient was estimated utilizing the LMC Extinction Retrieval Service at the MCPS data products section website (http://djuma.as.arizona.edu/~dennis/lmcext.html). Using all the stars within 10 arc minutes search radius (1689 objects) Av=0.6+/-0.45 was estimated.
Hence, taking into account the distance modulus to the LMC (m-M)0=18.515+/-0.085 mag (Clementini et al. 2003) the following extinction corrected colors are obtained:
(B-V)0=0.25+/-0.21;
(V-I)0=-0.011+/-0.554,
along with absolute magnitude of the object:
V0=2.0+/-0.5.
According to Gaia Collaboration et al. 2018 (Gaia Data Release 2; see their Figure 1) the object should be present in both Gaia data releases, but probably it is not reliably detected due to crowding. The calculated extinction corrected colors and absolute V band magnitude of the archival object are consistent with a FOIII - F5III star at the distance of the LMC. This object probably is the donor star of the binary system. Taking into account the MCPS data, the amplitude of the outburst is ~8.3+/-0.1 magnitudes in V band at the moment of the approximate maximum.