Photometric behaviour of the FU Orionis type star, V1057 Cygni, during the last 25 years

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1 MNRAS 434, (2013) Advance Access publication 2013 July 8 doi: /mnras/stt963 Photometric behaviour of the FU Orionis type star, V1057 Cygni, during the last 25 years E. N. Kopatskaya, 1 E. A. Kolotilov 2 and A. A. Arkharov 3 1 Astronomical Institute, St Petersburg State University, Universitetskij Pr. 28, Petrodvorets, St Petersburg, Russia 2 Sternberg Astronomical Institute of Moscow State University, University avenue 13, Moscow, Russia 3 Main (Pulkovo) Astronomical Observatory of Russian Academy of Sciences, Pulkovskoye chaussee 65/1, St Petersburg, Russia Accepted 2013 May 31. Received 2013 May 26; in original form 2012 September 16 ABSTRACT The FU Orionis type of variable star (FUor), V1057 Cygni, underwent a nova-like outburst in Among the FUors, V1057 Cyg is notable for having the most dramatic postmaximum decrease in brightness. Thus, photometric monitoring of this object is important for interpretations of the cause of this event. Here, we study the behaviour of V1057 Cyg over the last 25 years on the basis of our optical and infrared observations. The optical and near-infrared observations of V1057 Cyg started in 1974, and we present all our data (up to the end of 2011), including 1085 and 167 nights of optical and infrared photometry, respectively. The UBVRIJHKLM light curves for show that despite the increased photometric activity, after a rapid decrease in brightness in the mid-1990s, the average level of brightness remained practically constant. After the object becomes fainter than V 11.5 mag, a swerve appears in the track of the colour magnitude diagram. The light variability shows a different periodicity in different spectral regions. We have discovered a period of 1631 ± 60 d in the BVR bands ( ) and 523 ± 40 d in the RIJHK bands ( ) with amplitudes of mag. The 523-d period is presumably correlated with the changes in the radial velocity of an emission component in Li I. We conclude that the observed properties of the FUor star V1057 Cyg are in accordance with current models of FUors involving binary or multiple systems. Key words: stars: individual: V1057 Cygni stars: pre-main sequence stars: variables: general. 1 INTRODUCTION Studies of the photometric variability of pre-main-sequence (PMS) stars are important for understanding the early stages of stellar evolution. Among these PMS stars, a small group called FU Orioinis type objects (FUors) is notable. Their photometric behaviour is characterized by a dramatic increase in optical brightness (up to 5 mag) followed by a slower decline. The time-scale for this decline is very different for different FUors (Herbig 1977; Kolotilov 1991; Clarke et al. 2005). In the mid-1980s, Hartmann & Kenyon (1985) put forward a hypothesis, according to which the outburst is the result of a sudden increase in the accretion rate through the circumstellar disc surrounding these stars, leading to an increasing luminosity of the disc (see also the reviews by Hartmann & Kenyon 1996; Reipurth, Herbig & Aspin 2010). Now, the accretion disc model is generally enik1346@rambler.ru accepted. A different view of the nature of FUors is that of a single star, rotating at a speed close to breakup velocity, and with a strong stellar wind (Larson 1980; Petrov & Herbig 1992; Herbig 2009). In the accretion disc hypothesis, the most important question is the following: what is the cause of the sharp increase of the accretion rate producing a outburst? Bonnell & Bastien (1992) have suggested that FUors might represent close binary systems. This supposition gained support with the work of Wang et al. (2004), who discovered the close companion of FU Ori itself, which was determined to be a PMS star, presumably of spectral class K, with a substantial infrared (IR) excess. Beck & Aspin (2012) have established that the fainter component, FU Ori S, is actually the more massive star in the binary. In this case, the flare activity of the FUor can be induced during the orbital approach of the companions to each other (Malbet et al. 2005). It is also possible that the source of the accretion instability might be a massive planet (10 15 M Jup,whereM Jup is the Jovian mass) embedded into the disc (Lodato & Clarke 2004). Problems connected with the thermal ionization instability of the disc near the young star, in connection with the FUor flares, have C 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

2 Photometric behaviour of the FUor V1057 Cyg 39 been considered in detail by Clarke, Lin & Pringle (1990). Reipurth & Aspin (2004, 2010) have argued that the FUor outburst might be a consequence of disintegration of an unstable triple system. This scenario is supported by the recent discovery of the multiple PMS system, HBC 515 (Reipurth et al. 2010). The brightest and most well-studied FUors are FU Ori itself, Z CMa, V1057 Cyg and V1515 Cyg, and their optical light curves have been investigated by Clarke et al. (2005). The star V1057 Cyg, which brightened in by 5 mag (Herbig 1977), is now distinguished within the FUor group because it has the most rapid decrease in brightness after maximum. Analyses of the light curves of V1057 Cyg in optical and IR bands have been carried out earlier by Kopatskaya (1984), Ibragimov & Shevchenko (1987), Simon & Joyce (1988), Kolotilov (1990), Kenyon & Hartmann (1991), Kolotilov & Kenyon (1997), Kolotilov (1991), Kopatskaya et al. (2002) and Clarke et al. (2005). Ábrahám et al. (2004) have analyzed changes in V1057 Cyg in the IR, µm, as observed between 1983 (ground-based measurements and measurements from the IRAS) and period (observations from the Two-Micron All-Sky Survey and the Infrared Space Observatory). They have noted a substantial decrease of the 1 10 µm brightness during that time interval, but no noticeable changes have been seen in other spectral regions, up to 100 µm. This indicates the existence of an extended relic dust envelope surrounding V1057 Cyg and its disc. Both the analysis of the energy distribution in a wide range of wavelengths (Turner, Bodenheimer & Bell 1997) and the interferometric IR observations (Millan-Gabet et al. 2006) indicate that such an envelope is present. The possible geometric models of an extended dust envelope of V1057 Cyg have been analysed by Green et al. (2006) and Quanz et al. (2007), and the associated dust formation has been noted by Kolotilov (1990) and Kolotilov & Kenyon (1997). We started the photometric observations of V1057 Cyg using different telescopes in the mid-1970s, shortly after the outburst, which took place in In this paper, we present the results of all measurements that we have performed up to now (a substantial portion of the observations was published earlier). In particular, we discuss the photometric behaviour of the object after its brightness decrease in the mid-1990s. 2 OBSERVATIONS 2.1 Data Optical UBVR observations of the object were started in 1974, using the 48-cm reflector of the Byurakan Station (Armenia) of the Astronomical Observatory of Leningrad (now St Petersburg) State University (Kopatskaya 1984). Later, photometry in the UBVR C I C bands was performed using the 70-cm AZT-8 telescope of the Crimean Astrophysical Observatory (Nauchny, Ukraine) and the LX200 telescope in Petrodvorets (St Petersburg) with the use of the CCD ST-7XME. The standard methods of dark subtraction and flatfield correction were applied in the data reduction. The computer software package developed at the Astronomical Institute of the St Petersburg State University (SPbSU) was used for the aperture photometry. In order to secure the comparison with data published earlier, we have transformed our RI C photometry into the Johnson system by using the formulae given by Fernie (1983) for very red stars. The reduced magnitudes coincide, within the measurement errors, with the magnitudes measured by Ibragimov (see Clarke et al. 2005). In , IR JHK photometry was performed using the AZT-24 telescope of the Pulkovo Observatory installed at Campo Imperatory (Italy). Unfortunately, these observations were interrupted at the beginning of 2009 because of a strong earthquake and were resumed only in summer The optical UBV and IR JHKLMN photometric observations of V1057 Cyg were started in 1976 using the 60-cm and 125-cm telescopes of the Crimean Laboratory (Nauchny, Ukraine) of the Sternberg Astronomical Institute of Moscow State University. Details of the techniques have been presented previously by Kolotilov (1990). In our previous papers, we have presented the results of the optical photometry only as the averages over 50 d (Kopatskaya 1984) or over years (Kolotilov 1990; Kopatskaya et al. 2002). In this paper, we present the electronic version of the original optical observations (1085 nights) and the IR JHK observations (167 nights); see Tables 1 and 2. Table 1. Optical photometry of V1057 Cyg performed in the period JD U B V R C I C R J I J Obs kop kol kop kol kop Table 2. JHKLM photometry of V1057 Cyg performed in the period JD J H K L M Obs JD J H K L M Obs Ar Ar Ar Sh Ar Sh Ar Sh Ar Sh

3 40 E. N. Kopatskaya, E. A. Kolotilov and A. A. Arkharov Table 3. Collective V-band light curve of V1057 Cyg from pre-outburst up to JD V JD V JD V JD V Figure 1. Optical light curves of V1057 Cyg in : dots, our observations; squares, observations by Ibragimov (see Clarke et al. 2005). We also present the electronic version of the collective light curve of V1057 Cyg in the V band for (Table 3). This is based on our observations and the published data from 24 papers. References are listed in the footnotes to Table 3. All three tables can be found in the online Supporting Information and at Figs 1 and 2 show the corresponding light curves in the optical and IR regions from 1985 to Light curves and colour indices As noted above, the nova-like increase in the brightness of the FUor V1057 Cyg took place in Kolotilov (1990) has noted that in the post-maximum history, from 1984 to 1988, the brightness of the object was almost constant. This plateau lasted for nearly 10 yr, after which, in the mid-1990s, a prominent rapid decrease was observed (Kolotilov & Kenyon 1997; Ibragimov 1999; Kopatskaya et al. 2002). Fig. 1 shows the light curve of V1057 Cyg, obtained in the UBVRI bands from 1985 to mid There has been no significant downward trend of brightness since 1997, and we refer to this part as the second plateau, which lasted for more than 14 yr, with a substantial photometric variability. In Fig. 3(a), we plot the V1057 Cyg light curve in the V band from before the outburst up to It is clear that the object still remains approximately 1.5 mag brighter than it was before the outburst. The fast decrease of brightness occurred in the mid-1990s. It is known that the outburst of V1057 Cyg was accompanied by a strong mass outflow (Kolotilov 1983; Hartmann, Hinkle & Calvet 2004; Herbig 2009). This is confirmed by the evolution of the optical colour indices U B, B V, V R and V I of V1057 Cyg. Fig. 3(b)

4 Photometric behaviour of the FUor V1057 Cyg 41 Figure 2. Light curves of V1057 Cyg in the JHKLM bands: black circles, our observations; open squares, observations by Simon & Joyce (1988); open triangles, observations by Kenyon & Hartmann (1991). Figure 3. (a) V1057 Cyg light variations in the V band fitted to an exponential decline; the long-dashed line marks the brightness level V = 11.5 mag. (b) Diagram of V (B V). The solid line indicates the direction of the extinction vector, for a standard interstellar extinction law. The long-dashed line is the same as in (a). shows how the B V variations depend on the V brightness. It can clearly be seen that when the star became fainter than V 11.5 mag, the colour index changed significantly, thus demonstrating the blueness effect. The gap in the diagram is a result of the rapid decrease in brightness, which occurred during an invisibility season. A similar behaviour of V1057 Cyg is observed in other optical colour indices. The same blueness effect also occurs during brightness decreases in young UX Orionis type stars, and is explained by a relative increase in the contribution of scattered light (Grinin 1988). The effect is also observed in some T Tauri stars. Fig. 2 shows our observations, obtained in the JHKLM bands from 1985 to the present. Here, we have also compiled some data for from Simon & Joyce (1988), and the data for from Kenyon & Hartmann (1991). A comparison of Figs 1 and 2 shows that, in general, the behaviour of the IR emission in the JHK bands and the optical bands is similar (i.e. the first plateau, then the decrease and, finally, the second plateau).

5 42 E. N. Kopatskaya, E. A. Kolotilov and A. A. Arkharov However, the decrease of brightness, at least in H and K, began 1000 d later than in the optical bands. The variability observed during the last 10 yr in the JHK bands is similar to the variability in the I band. With regards to the emission in the LM bands, we can say that the second plateau is also observed. In spite of the scarcity of observations, we also note variations up to 0.3 mag in recent years. The average levels of brightness for the intervals and are almost identical. The average levels for the whole interval are U = mag, B = mag, V = mag, R = mag, I = 9.36 mag, J = 8.17 mag, H = 7.00 mag, K = 6.22 mag, L = 4.88 mag and M = 4.65 mag. Accepting A v = 3.7 mag, according to Green et al. (2006), and a normal law of extinction, we obtain V 0 = 8.94 mag, (U B) 0 = 0.56 mag, (B V) 0 = 0.82 mag, (V R) 0 = 0.82 mag, (V I) 0 = 1.17 mag, (V J) 0 = 1.77 mag, (V H) 0 = 2.63 mag, (V K) 0 = 3.04 mag, (V L) 0 = 4.16 mag and (V M) 0 = 4.25 mag. At a distance of pc, the values in the UBVR bands conform to those of a giant of spectral class G0-2, which agrees with the estimation made by Herbig et al. (2003) for In this paper, we do not discuss this spectrum of the star or the accretion disc, which resembles a star in observational respects, as suggested by Kravtsova et al. (2007) on FU Ori. At least two long time-scales of variability can be discerned in the light curves: (i) a slow one, with a time-scale of thousands of days, which started after 1995; (ii) a faster one, with a characteristic time-scale of hundreds of days, which can be traced over the entire period after the outburst (see Ibragimov & Shevchenko 1987). The slow component is obviously present in BVR, with the amplitude of variability slightly decreasing with wavelength. 2.3 Search for periodicity We have investigated the UBVRIJHK light changes for periodicity. In the power spectra of the BVR data, there is a pronounced peak corresponding to a period of d (i.e. approximately 4.5 yr). In order to cover more than two periods, we have investigated the data since At that time, the smoothness of the light curve was still apparent, and therefore it has been removed. For the V band, where the slow component is best observed, relative light variations have been analysed by means of the CLEAN program. We have found a period of 1631 ± 60 d, with an amplitude of 0.5 mag. The data in B and R also reflect this period, with amplitudes of 0.6 mag in B and 0.3 mag in R. Figs 4(b) (d) show the phased light curves for the relative light variations in the BVR. The periodicity in the U band has not been detected (see Fig. 4a); instead, the data show irregular variability strongly exceeding the expected amplitude of a periodic component. In the I band, we only have a sufficient number of observations for analysis after As is evident from Fig. 4(e), the data do not show a slow component, and are therefore the most suitable in the search for periodicity in the fast component. For this purpose, we have used data from For the BVR data, the wave form in the variations of the slow component was subtracted from the initial light curves. The residual light variations are shown in Fig. 5. Using a CLEAN analysis, we have found that the I-band data fluxes are modulated with a period of 523 ± 40 d. The amplitude of the variability is I = 0.5 mag (see Fig. 6e). As is obvious from the phase curves presented in Figs 6(a) (d), a period of 523 d with amplitude R = 0.3 mag is present in the R-band data, but absent in the U-, B- andv-band data. This period is also present in the near-ir. Light curves in the JHK bands are Figure 4. UBVRI-band phased light curves of V1057 Cyg. The smooth decrease of the flux has been removed from the BVR data. The period is 1631 ± 60 d. Figure 5. Light variations in the BVR bands after the removal of slow components. very similar, so we present the combined phased curve for JHK in Fig. 7. The data in the J and K bands are shifted by the zero-points, which correspond to average colour indices J H = 1.15 mag for J and H K = 0.80 mag for K.

6 Photometric behaviour of the FUor V1057 Cyg 43 Figure 7. The collective phase curve of V1057 Cyg in the JHK bands. The J and K magnitudes are scaled to H by using average colour indices (see text). Designations are: J, circles; H, squares; K, triangles. The period in the near-ir bands is 523 ± 40 d. Figure 8. Temporary variations of the I-band brightness (dots, left axis) and radial velocity of the Li λ6707 Å emission component (black circles, right axis). Three observations strictly matching in time are designated by open circles with dots for brightness and by large black circles for radial velocity. Figure 6. UBVRI light curves plotted against phase with a 523-d period. In the BVR bands, data were analysed after the removal of long-term fluctuations (see text and Fig. 5). 2.4 Possible correlation between the photometric and spectral variability The spectrum of V1057 Cyg changed significantly from one season to another after the outburst (Petrov et al. 1998; Herbig, Petrov & Duemmler 2003; Hartmann et al. 2004; Herbig 2009). Thus far, no connection has been found between the spectral and photometric variability. For instance, Clarke et al. (2005) used the observations of 1996 to search for the short-term relations between the brightness in the V band and the quasi-periodic variations of the doublepeaked photospheric absorption lines detected by Herbig et al. (2003). No apparent correlation was found. Besides, the number of overlapping spectral and photometrical observations is not significant, unfortunately. We have also used our observations to search for a relation between changes of spectral details and brightness changes. It is known that after the decline in brightness in the mid- 1990s, the spectrum changed most significantly. Herbig (2009) has investigated in detail the variable multicomponent structure of low-excitation lines, in particular, the line Li I λ6707 Å. We have not found any connection between the changes of the radial velocities of the absorbing components and the flux variability of V1057 Cyg. However, the radial velocities and equivalent widths of the red wing and the narrow emission components in the Li I line have been observed, at least since 1997 (see table 1 in Herbig 2009). Similar peaks have also been observed at the other stronger lines of neutral elements. A comparison of Herbig s data with our photometric data allows us to suggest that the changes of the radial velocity are correlated with the fast component of the flux variability (i.e. they correlate with the changes of brightness in the bands from R to K). Fig. 8 reproduces part of the light curve in the I band (dots and left axis) and the temporary variations of the radial velocity (black circles and right axis). We have nine photometric points, out of which three are simultaneous in time with the spectroscopic

7 44 E. N. Kopatskaya, E. A. Kolotilov and A. A. Arkharov Figure 9. Phase curve of the radial velocity of the Li λ6707 Å emission component (large circles, right axis), plotted together with the phase curve of the I-band brightness (dots, left axis). observations. These are designated by open circles with dots for brightness and by large black circles for radial velocity. Photometric errors in the I-band data are less than 0.01 mag. Radial velocity errors are not given by Herbig (2009), but data from the literature (e.g. Bubar et al. 2007; Frebel et al. 2010) show that the radial velocity, estimated from observations made with the same equipment under similar conditions, has errors of less than 1 km s 1.So, we believe that the similarity of the two curves in Fig. 8 is not a coincidence. Therefore, it is possible that the changes in the emission components of the neutral element lines are periodical. Fig. 9 shows the phase curve of these changes for the Li λ6707-å line, with a 523-d period, where the axis of the radial velocity is on the right. In the same figure, we also plot part of Fig. 6(e), with the I brightness axis on the left. 3 DISCUSSION V1057 Cyg was classified as a T Tau type star before the outburst (Herbig 1977). Typical photometric periods for these stars (P 15 d) have been related to axial stellar rotation (cold spots or hotspots on the surface). Longer periods have also been observed (with P = d; e.g. Artemenko, Grankin & Petrov 2010), which are possibly caused by the Keplerian motion of protoplanets or dust clouds in the circumstellar discs. In addition, for several seasons at the beginning of the 1980s, V1057 Cyg showed photometric periodicity on short time-scales, P = 11.6 d (post-maximum brightness recession; Ibragimov & Shevchenko 1987), and a 14-d period only in 1989 (Clarke et al. 2005). We have found periods of P = 1631 ± 60dintheBVR bands in the period and P = 523 ± 40dintheRIJHK bands in the period (i.e. the second photometric plateau). A periodicity appears after the luminosity generated in an outburst has strongly diminished. In the models developed by Kenyon & Hartmann (1991), Clarke et al. (2005) and Zhu et al. (2009) see also references therein the main source of radiation is the accretion disc. The presented longterm periodicity and the fact that the period in the near-ir is shorter than in the optical cannot be explained by some irregularities in the rapid rotation of the Keplerian disc of a single star. Additional source components have been repeatedly invoked for an explanation of the triggering of an outburst. Bonnell & Bastien (1992) were first to suggest that FUors are binaries. In this case, the outburst can be stimulated either by the close approach of the components, as assumed by Malbet et al. (2005), or by the perturbing influence of a planet with a mass of about 10 times the mass of Jupiter, embedded in the disc and orbiting around the star, as suggested by Lodato & Clarke (2004) and Clarke et al. (2005). In particular, Nayakshin & Lodato (2012) have shown that if there is a massive young planet in the inner disc, then some tens of years after an outburst, the accretion rate on to the protostar might be strongly variable on different timescales, including a few years. The resulting variations of temperature could lead to the brightness variability. Two periods observed in different spectral ranges might indicate the presence of a stellar component in V1057 Cyg. Reipurth (2000) has shown that the dynamical decay of triple or multiple systems leads to strong outflow activity. Reipurth & Aspin (2004, 2010) have discussed the hypothesis that FUors might be newborn binaries that become bound when a small non-hierarchical multiple system breaks up. The calculations by Demidova, Grinin & Sotnikova (2010) have shown that in young binary systems with a secondary low-mass component and an accretion disc, cyclic variations of the flux with a substantial amplitude can be observed, depending on the accretion rate, orbital period and orientation in space. FU Ori itself is a wide binary (Wang et al. 2004), and Malbet et al. (2005) suspect the presence of a hotspot in the disc or a stellar companion in the central FU Ori system at a distance of 10 au. If one of the long time-scale periods in the variability of V1057 Cyg is a consequence of the orbital motion of the low-mass component, then for a circular orbit the distance between the components is a few au or 10 mas at a distance of pc. A period of 523 d is observed in the RIJHK bands, and the brightness in these bands is correlated with changes in the emission component of low excitation lines. During the last two decades, because there have been highresolution interferometric observations of T Tau stars, a great number of double and multiple systems, including T Tau itself, have been revealed (e.g. Brandeker et al. 2001; Koresko 2000; Duchêne et al. 2003; Berger et al. 2011; Müller et al. 2011). Recently, with the help of adaptive optics imaging, Reipurth et al. (2010) have found the companion that is responsible for the radiation in the middle IR-range in the multiple PMS system HBC 515 in L The structures of the Li I line and some other lines with low-excitation potential in HBC 515 are very similar to those observed in V1057 Cyg. Thus, one of the components in V1057 Cyg might be a star of spectral class K or later. Interferometric observations with high resolution have spatially resolved V1057 Cyg in the K band (Wilkin & Akeson 2003; Millan- Gabet et al. 2006; Eisner & Hillenbrand 2011). Geometric representations of the brightness distribution by a Gaussian have 1 au FWHM. This is much less than our rough estimates. However, in order to resolve both components, interferometric observations at shorter wavelengths should be performed. We believe that the assumption of binarity seems likely to be correct, but it is necessary to ascertain that the determined periods are stable in time. The relationship between the emission components in the Li I line and brightness also needs to be confirmed by means of a larger number of simultaneous observations.

8 Photometric behaviour of the FUor V1057 Cyg 45 4 CONCLUSION The study of FUors is very important for the understanding of the earliest phases of stellar evolution. The number of known FUors is small, and moreover the light curves can be very different from case to case. In this paper, we have presented all of our optical and near-ir observations of V1057 Cyg collected since the mid- 1970s and we have focused on the behaviour during the last 25 yr. We have analysed periodic flux variations that occurred after the decay in flux of the object in the mid-1990s and we have found two different time-scales with long periods, in both optical and near-ir light. We suggest that these fluctuations reflect binarity, as has also been proposed in current models of FUors. V1057 Cyg deserves to be studied further using photometric observations combined with spectroscopy and high-resolution interferometric observations at shorter wavelengths. ACKNOWLEDGEMENTS We are grateful to V. I. Shenavrin for providing us with IR observations and to V. M. Larionov for performing observations and giving helpful criticism and useful advice during the preparation of this paper. REFERENCES Ábrahám P., Kóspál Á., Csizmadia Sz., Kun M., Moór A., Prusti T., 2004, A&A, 428, 89 Artemenko S. A., Grankin K. N., Petrov P. P., 2010, Astron. Rep., 54, 163 Beck T. L., Aspin C., 2012, AJ, 143, 55 Berger J.-P. et al., 2011, A&A, 529, L1 Bonnell I., Bastien P., 1992, ApJ, 401, L31 Brandeker A., Liseau R., Artimowicz P., Jayawardhava R., 2001, ApJ, 561, L199 Bubar E. J., King J. R., Soderblom D. R., Deliyannis C. P., Boesgaard A. M., 2007, AJ, 134, 2328 Clarke C. J., Lin D. N. C., Pringle J. E., 1990, MNRAS, 242, 439 Clarke C. J., Lodato G., Melnikov S. Y., Ibrahimov M. A., 2005, MNRAS, 361, 942 Demidova T. V., Grinin V. P., Sotnikova N. Ya., 2010, Astron. Lett., 36, 498 Duchêne G., Ghez A. M., McCabe C., Weinberger A. J., 2003, ApJ, 592, 288 Eisner J. A., Hillenbrand L. A., 2011, ApJ, 738, 9 Fernie J. D., 1983, PASP, 95, 782 Frebel A., Simon J. D., Geha M., Willman B., 2010, ApJ, 708, 560 Green J. D., Hartmann L., Calvet N., Watson D. M., Ibrahimov M., Furlan E., Sargent B., Forrest W. J., 2006, ApJ, 648, 1099 Grinin V. P., 1988, SvAL, 14, 27 Hartmann L., Kenyon S. J., 1985, ApJ, 299, 462 Hartmann L., Kenyon S. J., 1996, ARA&A, 34, 207 Hartmann L., Hinkle K. H., Calvet N., 2004, ApJ, 609, 906 Herbig G. H., 1977, ApJ, 217, 693 Herbig G. H., 2009, AJ, 138, 448 Herbig G. H., Petrov P. P., Duemmler R., 2003, ApJ, 595, 384 Ibragimov M. A., 1999, IBVS, 4691, 1 Ibragimov M. A., Shevchenko V. S., 1987, Astrophysics, 27, 337 Kenyon S. J., Hartmann L., 1991, ApJ, 383, 664 Kolotilov E. A., 1983, SvAL, 9, 324 Kolotilov E. A., 1990, SvAL, 16, 12 Kolotilov E. A., 1991, SvAL, 17, 144 Kolotilov E. A., Kenyon S. J., 1997, IBVS, 4494, 1 Kopatskaya E. N., 1984, Astrophysics, 20, 138 Kopatskaya E. N., Grinin V. P., Shahovskoi D. N., Shulov O. S., 2002, Astrophysics, 45, 143 Koresko C. D., 2000, ApJ, 531, L147 Kravtsova A. S., Lamzin S. A., Errico L., Vittone A., 2007, Astron. Lett., 33, 755 Larson, 1980, MNRAS, 190, 321 Lodato G., Clarke C. J., 2004, MNRAS, 353, 841 Malbet F. et al., 2005, A&A, 437, 627 Millan-Gabet R. et al., 2006, ApJ, 641, 547 Müller A., Carmona A., van den Ancker M. E., van Boekel R., Henning Th., Launhardt R., 2011, A&A, 535, L3 Nayakshin S., Lodato G., 2012, MNRAS, 426, 70 Petrov P. P., Herbig G. H., 1992, ApJ, 392, 209 Petrov P. P., Duemmler R., Ilyin I., Tuominen I., 1998, A&A, 331, L53 Quanz S. P., Henning T., Bouwman J., van Boekel R., Juhász A., Linz H., 2007, ApJ, 668, 359 Reipurth B., 2000, AJ, 120, 3177 Reipurth B., Aspin C., 2004, ApJ, 608, L65 Reipurth B., Aspin C., 2010, in Harutyunyan H., Mickaelian A., Terzian Y., eds, Evolution of Cosmic Objects through their Physical Activity. Gitutyun Publishing House, Yerevan, Armenia, p. 18 Reipurth B., Herbig G., Aspin C., 2010, AJ, 139, 1668 Simon T., Joyce R. R., 1988, PASP, 100, 1549 Turner N. J. J., Bodenheimer P., Bell K. R., 1997, ApJ, 480, 754 Wang H., Apai D., Henning T., Pascucci I., 2004, ApJ, 601, L83 Wilkin F. P., Akeson R. L., 2003, Ap&SS, 286, 145 Zhu Z., Hartmann L., Gammie C., McKinney J. C., 2009, ApJ, 701, 620 SUPPORTING INFORMATION Additional Supporting Information may be found in the online version of this article. Table 1. Optical photometry of V1057 Cyg performed in the period Table 2. JHKLM photometry of V1057 Cyg performed in the period Table 3. Collective V-band light curve of V1057 Cyg from preoutburst up to 1990 ( doi: /mnras/stt963/-/dc1). Please note: Oxford University Press are not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article. This paper has been typeset from a TEX/LATEX file prepared by the author.