GR Ori (Nova Ori 1916)

GR Ori was discovered as a possible nova in 1916. It was recorded at a photographic magnitude of 11.5 on January 30 and faded to 13.0 on February 8. GR Ori has been identified as a 22.8 magnitude blue object. The object has been considered as a distant nova although due to the color there was a suggestion of a WZ – Sge type dwarf nova.

The first detected outburst in 97 years!

On February 11.476 UT 2013, I detected an outburst of GR Ori at magnitude 13.0. An alert notice was sent and the object was quickly confirmed by observers around the world.

Simone Scaring was at the 1.2 meter Mercator Telescope located at the Rogue de Los Muchachos Observatory on La Palma Island (Spain). A spectrum was taken on February 12, but not much emission/absorption lines were seen which indicated a dwarf nova outburst.

Outburst image below was taken by Denis Buczynski, Tarbatness Observatory, UK.

gr_ori_20130211_3x120_R

Spectroscopic confirmation of the dwarf nova nature of GR Orionis

ATel #4811; Akira Arai (Nishi-Harima Astronomical Observatory, University
of Hyogo), Daisaku Nogami(Kyoto University) on behalf of the Optical
and Infrared Synergetic Telescopes for Education and Research (OISTER)
on 14 Feb 2013; 12:40 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Akira Arai (arai@nhao.jp)

Subjects: Optical, Cataclysmic Variable, Nova, Transient, Variables

We spectroscopically observed GR Ori with the 2.0-m Nayuta Telescope at Nishi-Harima Astronomical Observatory on 2013 February 13. This observation was carried out with the low resolution mode (R~1,000) of the optical spectrograph MALLS which covers the wavelength of 4,000-6,800 A. GR Ori was discovered as a possible nova in 1916 (Thiele 1916, Astron. Nachr., 202, 213), but has long been suspected to be a dwarf nova (e.g. McLaughlin 1945, AJ, 51, 136; Kato et al. 2012, PASJ, 64, 63). The second outburst of GR Ori was found by R. Stubbings on 2013 Feb. 11.476 (UT) at 13.0 mag (vsnet-outburst 15096). Our spectra of this star obtained around 2013 Feb. 13.53 (UT) have a blue continuum showing H-alpha in absorption with an emission core, H-beta in absorption (FWZI~1,800 km/s), and possibly He I 5876 in emission, which give evidence of the dwarf nova nature of GR Ori. Follow-up observations are being continued by OISTER.

Further observations from CCD observers have revealed the presence of superhumps and the classification of this star is a new WZ -Sge type dwarf nova.

The AAVSO light curve of GR Ori is shown with a re-brightening observed at magnitude 16.0. My outburst detection is shown as (SRX)

gr ori

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