Naslov
Investigating the past history of EXors: the cases of V1118 Orionis, V1143 Orionis, and NY Orionis
(Investigating the past history of EXors : the cases of V1118 Ori, V1143 Ori, and NY Ori)

Autori
Jurdana-Šepić, Rajka ; Munari, Ulisse ; Antoniucci, Simone ; Giannini, Teresa ; Li Causi, Gianluca ; Lorenzetti, Dario

Izvornik
Astronomy & astrophysics (Berlin) (0004-6361) 602 (2017); A99, 7

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
stars: pre-main sequence ; stars: variables: T Tauri, Herbig Ae/Be ; catalogs ; stars: individual: NY Ori ; stars: individual: V1118 Ori ; stars: individual: V1143 Ori

Sažetak
EXor objects are young variables that show episodic variations of brightness commonly associated to enhanced accretion outbursts. Aims. With the aim of investigating the long- term photometric behaviour of a few EXor sources, we present here data from the archival plates of the Asiago Observatory, showing the Orion field where the three EXors V1118, V1143, and NY are located. Methods. A total of 484 plates have been investigated, providing a total of more than 1000 magnitudes for the three stars, which cover a period of about 35 yrs since 1959 to 1993. Our data are compared with literature data. Results. Apart from a newly discovered flare-up of V1118, we identify the same outbursts already known, but we provide two added values: (i) a long-term sampling of the quiescence phase ; and (ii) repeated multi- colour observations (BVRI bands). The former allows us to give a reliable characterization of the quiescence, which represents a unique reference for studies that will analyze future outbursts and the physical changes induced by these events. The latter is relevant to confirm whether the intermittent increases of brightness are accretion-driven (as in the case of V1118), or extinction-driven (as in the case of V1143). Accordingly, doubts arise about the V1143 classification as a pure EXor object. Finally, although our plates do not separate NY Ori and the star very close to it, they indicate that this EXor did not undergo any major outburst during our 40 yrs monitoring.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA