The outburst of the bright CV ASASSN-14ho

ATel #6619; J. L. Prieto (Diego Portales; MAS), L. Sturch (BU), B. Madore (Carnegie Observatories), A. B. Davis, K. Z. Stanek, G. Simonian, T. W.-S. Holoien, C. S. Kochanek, U. Basu, J. F. Beacom (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), D. Bersier (LJMU), J. Brimacombe (Coral Towers Observatory), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 24 Oct 2014; 19:59 UT
Credential Certification: Jose L. Prieto (jose.prietok@mail.udp.cl)

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We report optical imaging and spectroscopy of the bright transient ASASSN-14ho (RA = 06:30:27.3, DEC = -65:29:50.2, see ASAS-SN transients). We obtained a low resolution optical spectrum on UT 2014 Sep 25.4 with the WFCCD spectrograph mounted on the du Pont 2.5m telescope at LCO. The spectrum shows H-alpha and He II 4686 lines in emission, as well as other Balmer lines in absorption with emission-line cores (see this figure). The H-alpha has a red asymmetry and can be well fit with two Gaussians centered at -200 and +200 km/s. This is consistent with a Galactic CV in outburst.

The ASAS-SN light curve of ASASSN-14ho shows an outburst starting on UT 2014 Sep. 9.36, when it raised from V=15.4 on Sep. 6.37 to V=12.2 mag. The source then brightened to peak V=10.92 on Sep. 11.37 and declined slowly to V=11.88 on Oct. 2.33, when it started to decline faster to V=14.94 (~0.5 mag brighter than its quiescent magnitude) on Oct. 11.28. After this it showed two further re-brightenings and it had V=12.7 on Oct. 21.29. The full light curve can be found here.

ASASSN-14ho has a measured proper motion of pmRA = -16.9 +/- 1.7 mas and pmDEC = 60.5 +/- 1.7 mas in the SPM4 catalog (Girard et al. 2011), suggesting that this a nearby star. The pre-outburst source shows little variability in CRTS (Drake et al. 2009), has B-V=0.5 mag with an SED peaking at 2MASS J-band (see Vizier SED), and it is likely detected in ROSAT (1RXS J063029.4-653003). Follow-up observations are encouraged.