Asymmetrical nebula of the M33 variable GR290 (WR/LBV)^★

¹ Astronomical Institute of the Czech Academy of Sciences, Fričova 298, 25165 Ondřejov, Czech Republic
e-mail: olga.maryeva@asu.cas.cz
² Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, 119234 Moscow, Russia
³ Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Ave. Universidad s/n, 62210 Cuernavaca, Morelos, México
⁴ Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic
⁵ Special Astrophysical Observatory of the Russian Academy of Sciences, 36916 Nizhnij Arkhyz, Russia
⁶ Laboratory “Fast Variable Processes in the Universe”, Kazan Federal University, 420008 Kazan, Russia
⁷ Physics Department, Università di Roma “La Sapienza”, Piazza le Aldo Moro 5, 00185 Roma, Italy
⁸ INAF, Osservatorio Astronomico di Roma, Via Frascati 33, 00077 Monte Porzio Catone, Italy
⁹ Associazione Romana Astrofili, Via Carlo Emanuele I, n°12A, 00185 Roma, Italy
¹⁰ INAF – Istituto di Astrofisica e Planetologia Spaziali di Roma (IAPS-INAF), Via del Fosso del Cavaliere 100, 00133 Roma, Italy

Received: 3 October 2019
Accepted: 22 February 2020

Abstract

Context. GR 290 (M 33 V0532 = Romano’s star) is a luminous M 33 object undergoing photometric variability typical for luminous blue variable stars. It lies inside the Wolf-Rayet region in the Hertzsprung-Russell diagram and possesses a WN8-type spectrum at the light minima. Analysis of Gran Telescopio Canarias spectra obtained in 2016 led to the conclusion that it is surrounded by an unresolved H II region formed mostly of ejected material from the central star and revealed the presence of a second, more extended asymmetrical emission region.

Aims. The aim of this paper is to further explore the structure of the nearby environment of GR 290.

Methods. Long-slit spectra of GR 290 were obtained with three slit orientations in the visual and red spectral regions. The emission-line distribution for each slit was analyzed.

Results. We confirm the presence of an asymmetric H II region that extends ~50 pc to the south; ~30 pc to the north, and southeast; ~20 pc to the east and northwest; and ~10 pc to the west. We also present the first spectrum to be acquired of a star belonging to the neighboring OB 88 association, J013501.87+304157.3, which we classify as a B-type supergiant with a possible binary companion.