V2492 Cygni: Optical BVRI Variability During the Period 2010–2017

Abstract

Results from BV RI photometric observations of the young stellar object V2492 Cyg collected during the period from August 2010 to December 2017 are presented. The star is located in the field of the Pelican Nebula and it was discovered in 2010 due to its remarkable increase in the brightness by more than 5 mag in R-band. According to the first hypothesis of the variability V2492 Cyg is an FUor candidate. During subsequent observations it was reported that the star shows the characteristics inherent to EXor-and UXortype variables. The optical data show that during the whole time of observations the star exhibits multiple large amplitude increases and drops in the brightness. In the beginning of 2017 we registered a significant increase in the optical brightness of V2492 Cyg, which seriously exceeds the maximal magnitudes registered after 2010.

Evolution of Hubble wedges in episodic protostellar outflows

“…However, the observed luminosities of such protostars, and therefore by implication also their accretion rates, are typically much lower than one would expect, given their masses and formation time scales, and assuming steady accretion; this mismatch is called 'the luminosity problem' (Kenyon et al 1990(Kenyon et al , 1994Kenyon & Hartmann 1995). The luminosity problem can be mitigated if the accretion from the disc onto the protostar is episodic, with a large fraction of the accretion occuring in short intense events called outbursts (Offner & Mc-Kee 2011;Dunham & Vorobyov 2012;Cesaroni et al 2018;Hsieh et al 2018;Ibryamov et al 2018;Kuffmeier et al E-mail: rohde@ph1.uni-koeln.de 2018). Such outbursts are observed in FU Orionis type stars (FUors), which undergo a rapid increase in accretion rate, from ∼ 10 −7 M yr −1 to ∼ 10 −4 M yr −1 , for a period of order 10 years (Herbig 1966;Hartmann & Kenyon 1985;Hartmann et al 1989;Audard et al 2014;Safron et al 2015;Fehér et al 2017).…”

Spectroscopy of 9 eruptive young variables using TANSPEC

“…It has continued to show its highly variable behaviour after this latest episode of outburst. The physical origins of the variability observed in V2492 Cyg has been attributed to be driven by both UXortype extinction 3 and EXor-type accretion (Hillenbrand et al, 2013;Giannini et al, 2018;Ibryamov & Semkov, 2021). A paper describing about the detailed evolution of the various spectral features from previous outbursts till present times is currently under preparartion.…”

Csillagközi anyag és csillagkeletkezés a naprendszer néhány kiloparszekes környezetében

“…A V2492 Cyg az Észak Amerika/Pelikán-köd komplexumban található halvány, erősen beágyazott objektum volt egészen 2010-es kitöréséig. A fényességmaximum után halványodni kezdett, de 2016−2017 során a korábbi csúcsnál is nagyobb fényességnövekedést mutatott (Itagaki és Yamaoka, 2010;Covey és mtsai, 2011;Ibryamov és Semkov, 2017). A megfigyelt alacsonyabb akkréciós ráta és luminozitás miatt a csillagot általában nem tekintik klasszikus FUornak (Kóspál és mtsai, 2011).…”