AAVSO Special Notice #334


Outburst of the possible old nova GR Ori

February 11, 2013


Observer Rod Stubbings (Tetoora Road, Vic., Australia) reports an outburst of the suspected old nova GR Ori (== Nova Ori 1916), observing the star at a visual magnitude of 13.0 on 2013 February 11.476 UT (JD 2456334.976).  This observation was confirmed by observer Stephen Hovell (Kaitaia, New Zealand), who also reported the star at 13.0 on February 11.461. Mike Simonsen (Michigan, United States) notes that the suspected progenitor of this star has a magnitude around 22.8 in the Sloan Digital Sky Survey, suggesting a large outburst amplitude of 8-10 magnitudes, and that the star may be a WZ Sge-type dwarf nova rather than a

classical or recurrent nova. The overwhelming majority of observations of this star are fainter-than estimates, and the outbursting behaviour is poorly measured.  However, there have been instances of this object appearing bright over the past decade. Observations of GR Ori --

especially CCD time series -- are encouraged to help us better understand this object.


GR Ori is located at the following (J2000) coordinates:


      RA: 05 21 35.32 , Dec: +01 10 12.2



We note that the sequence for this star has since been updated by

M. Simonsen, and observers should obtain updated charts from AAVSO VSP:





Please promptly report all observation of this star to AAVSO WebObs

using the name "GR ORI".


This AAVSO Special Notice was prepared by M. Templeton.


Spectroscopic confirmation of the dwarf nova nature of

GR Orionis


ATel #4811; Akira Arai et. al.

(cvnet-outburst Feb 14 2013) 


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.





Fidusz (FIDRICH Robert)


email: fidusz@zpok.hu