A long-term photometric study of the FU Orionis star V 733 Cephei

Peneva, S.; Semkov, E.; Munari, U.; Birkle, K.

doi:10.1051/0004-6361/201014092

Cited by 32 publications

(37 citation statements)

References 25 publications

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“…FU Ori‐type stars (Herbig ; Greene et al ; Peneva et al ; Green et al ) provide the first piece of this evidence. These stars exhibit large increase in their brightness (∼5–6 mag).…”

Section: Introductionmentioning

confidence: 97%

Episodic accretion, protostellar radiative feedback, and their role in low-mass star formation

Stamatellos¹,

Whitworth²,

Hubber³

2012

Monthly Notices of the Royal Astronomical Society

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Protostars grow in mass by accreting material through their discs, and this accretion is initially their main source of luminosity. The resulting radiative feedback heats the environments of young protostars, and may thereby suppress further fragmentation and star formation. There is growing evidence that the accretion of material on to protostars is episodic rather than continuous; most of it happens in short bursts that last up to a few hundred years, whereas the intervals between these outbursts of accretion could be thousands of years. We have developed a model to include the effects of episodic accretion in simulations of star formation. Episodic accretion results in episodic radiative feedback, which heats and temporarily stabilizes the disc, suppressing the growth of gravitational instabilities. However, once an outburst has been terminated, the luminosity of the protostar is low, and the disc cools rapidly. Provided that there is enough time between successive outbursts, the disc may become gravitationally unstable and fragment. The model suggests that episodic accretion may allow disc fragmentation if (i) the time between successive outbursts is longer than the dynamical time‐scale for the growth of gravitational instabilities (a few kyr), and (ii) the quiescent accretion rate on to the protostar is sufficiently low (at most a few times 10−7 M⊙ yr−1). We also find that after a few protostars form in the disc, their own episodic accretion events shorten the intervals between successive outbursts, and suppress further fragmentation, thus limiting the number of objects forming in the disc. We conclude that episodic accretion moderates the effect of radiative feedback from young protostars on their environments, and, under certain conditions, allows the formation of low‐mass stars, brown dwarfs and planetary‐mass objects by fragmentation of protostellar discs.

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“…FU Ori‐type stars (Herbig ; Greene et al ; Peneva et al ; Green et al ) provide the first piece of this evidence. These stars exhibit large increase in their brightness (∼5–6 mag).…”

Section: Introductionmentioning

confidence: 97%

Episodic accretion, protostellar radiative feedback, and their role in low-mass star formation

Stamatellos¹,

Whitworth²,

Hubber³

2012

Monthly Notices of the Royal Astronomical Society

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“…FU Ori objects provide evidence of episodic accretion. These objects exhibit sudden luminosity increases on the order of ∼ 5 mag and estimated accretion rates of > 10 −4 M yr −1 which last from a few tens of years to a few centuries (Herbig 1977;Hartmann & Kenyon 1996;Greene et al 2008;Peneva et al 2010;Green et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The effect of radiative feedback on disc fragmentation

Mercer

Stamatellos

2016

Mon. Not. R. Astron. Soc.

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Protostellar discs may become massive enough to fragment producing secondary lowmass objects: planets, brown dwarfs and low-mass stars. We study the effect of radiative feedback from such newly-formed secondary objects using radiative hydrodynamic simulations. We compare the results of simulations without any radiative feedback from secondary objects with those where two types of radiative feedback are considered: (i) continuous, and (ii) episodic. We find that: (i) continuous radiative feedback stabilizes the disc and suppresses further fragmentation, reducing the number secondary objects formed; (ii) episodic feedback from secondary objects heats and stabilises the disc when the outburst occurs, but shortly after the outburst stops, the disc becomes unstable and fragments again. However, fewer secondary objects are formed compared to the the case without radiative feedback. We also find that the mass growth of secondary objects is mildly suppressed due to the effect of their radiative feedback. However, their mass growth also depends on where they form in the disc and on their subsequent interactions, such that their final masses are not drastically different from the case without radiative feedback. We find that the masses of secondary objects formed by disc fragmentation are from a few M J to a few 0.1 M . Planets formed by fragmentation tend to be ejected from the disc. We conclude that planetary-mass objects on wide orbits (wide-orbit planets) are unlikely to form by disc fragmentation. Nevertheless, disc fragmentation may be a significant source of free-floating planets and brown dwarfs.

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“…Due to the large-scale optical and infrared monitoring programs carried out in several observatories and the contributions of amateur astronomers, some new objects have been observed to undergo large amplitude outbursts, V733 Cep (Reipurth et al 2007;Peneva et al 2010), A&A 556, A60 (2013) V2493 Cyg Miller et al 2011;Kóspál et al 2011), V2492 Cyg (Aspin 2011;Hillenbrand et al 2013;Kóspál et al 2013), V2494 Cyg (Aspin et al 2009a), V2495 Cyg (Movsessian et al 2006), V900 Mon (Reipurth et al 2012), V2775 Ori (Fischer et al 2012).…”

Section: Introductionmentioning

confidence: 99%

“…The periods of enhanced accretion are thought to be triggered by thermal or gravitational instability in the circumstellar disk (Hartmann & Kenyon 1996;Zhu et al 2009). Another possible triggering mechanism could be the interactions of the circumstellar disk with a planet or nearby stellar companion on an eccentric orbit (Lodato & Clarke 2004;Reipurth & Aspin 2004;Pfalzner 2008). For a period of ∼100 years, the circumstellar disk adds ∼10 −2 M onto the central star and ejects ∼10% of the accreting material in a high-velocity stellar wind.…”

Section: Introductionmentioning

confidence: 99%

Photometric and spectroscopic variability of the FUor star V582 Aurigae

Semkov¹,

Peneva²,

Munari³

et al. 2013

A&A

Self Cite

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Aims. We present results from optical photometric and spectroscopic observations of the eruptive pre-main sequence star V582 Aur. Variability of the star was reported a few years ago when it was suspected as a possible FU Orionis object. Due to the small number of currently known FUors, a new object of this type is ideal target for follow-up photometric and spectroscopic observations. Methods. We carried out BVRI CCD photometric observations in the field of V582 Aur from 2009 August to 2013 February. We acquired high-, medium-, and low-resolution spectroscopy of V582 Aur during this period. To study the pre-outburst variability of the target and construct its historical light curve, we searched for archival observations in photographic plate collections. Both CCD and photographic observations were analyzed using a sequence of 14 stars in the field of V582 Aur calibrated in BVRI. Results. The pre-outburst photographic observations of V582 Aur show low-amplitude light variations typical of T Tauri stars. Archival photographic observations indicate that the increase in brightness began in late 1984 or early 1985 and the star reached the maximum level of brightness at 1986 January. The spectral type of V582 Aur can be defined as G0I with strong P Cyg profiles of Hα and Na I D lines, which are typical of FU Orionis objects. Our BVRI photometric observations show large amplitude variations (ΔV ∼ 2. m 8) during the 3.5 year period of observations. Most of the time, however, the star remains in a state close to the maximum brightness. The deepest drop in brightness was observed in the spring of 2012, when the brightness of the star fell to a level close to the pre-outburst. The multicolor photometric data show a color reversal during the minimum in brightness, which is typical of UX Ori variables. The corresponding spectral observations show strong variability in the profiles and intensities of the spectral lines (especially Hα), which indicate significant changes in the accretion rate. On the basis of photometric monitoring performed over the past three years, the spectral properties of the maximal light, and the shape of the long-term light curve, we confirm the affiliation of V582 Aur to the group of FU Orionis objects.

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A long-term photometric study of the FU Orionis star V 733 Cephei

Cited by 32 publications

References 25 publications

Episodic accretion, protostellar radiative feedback, and their role in low-mass star formation

Episodic accretion, protostellar radiative feedback, and their role in low-mass star formation

The effect of radiative feedback on disc fragmentation

Photometric and spectroscopic variability of the FUor star V582 Aurigae

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