Ysovar: The First Sensitive, Wide-Area, Mid-Infrared Photometric Monitoring of the Orion Nebula Cluster

Morales-Calderón, M.; Stauffer, J. R.; Hillenbrand, Lynne A.; Gutermuth, Robert; Song, Inseok; Rebull, L. M.; Plavchan, Peter; Carpenter, John M.; Whitney, B. A.; Covey, Kevin R.; Oliveira, Catarina Alves de; Winston, E.; McCaughrean, M. J.; Bouvier, J.; Guieu, S.; Vrba, F. J.; Holtzman, Jon A.; Marchis, Franck; Hora, J. L.; Wasserman, L. H.; Terebey, S.; Megeath, S. Thomas; Guinan, E. F.; Forbrich, Jan; Huélamo, N.; Riviére-Marichalar, P.; Barrado, D.; Stapelfeldt, K.; Hernández, Jesús; Allen, Lori; Ardila, D. R.; Bayo, A.; Favata, F.; James, D. J.; Werner, M. W.; Wood, Kenneth

doi:10.1088/0004-637x/733/1/50

Cited by 220 publications

(218 citation statements)

References 42 publications

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“…This could be due to long-term evolution in primordial disk structure. Follow-up observations with the Spitzer Space Telescope and the YSOVAR program will further constrain the long-term stability of the observed periodic variability (Morales-Calderon et al 2011). …”

Section: Discussionmentioning

confidence: 99%

“…YSOVAR has also obtained photometric time-series of YLW 16A at 3.6 and 4.5 μm during the Spitzer Space Telescope warm mission, which will be part of a separate future publication (Morales-Calderon et al 2011).…”

Section: Observationsmentioning

confidence: 99%

“…The observed variability is generally attributed to the rotational modulation of large cold spots, hot spots, accretion and disk veiling. Photometric variability driven by rotational modulation of the proto-star are less pronounced at infrared wavelengths, thus improving sensitivity to variability driven by disk-related processes and the subject of many recent near-infrared (NIR) and Spitzer Space Telescope studies such as YSOVAR (Morales-Calderon et al 2011;Flaherty et al 2012;Flaherty & Muzerolle 2010;Faesi et al 2012). …”

Section: Introductionmentioning

confidence: 99%

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The identification of 93 day periodic photometric variability for YSO YLW 16A

Plavchan

Güth

Laohakunakorn

et al. 2013

A&A

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Aims. Periodic variability in young stellar objects (YSOs) offers indirect evidence for an active dynamical mechanism. Starspots, accretion, stellar companions, and disk veiling can contribute to the photometric variability of YSOs. Methods. As part of an ongoing study of the ρ Oph star forming region, we report the discovery of 92.6 day periodic variations for the Class I YSO YLW 16A, observed over a period of three years. A SED model was fit to available photometric data for the object. Results. We propose a triple-system with an inner binary with a period of 93 days eclipsed by a warped circum-binary disk. The nature of the secondary is unconstrained and could be stellar or sub-stellar. We confirm the discovery of a tertiary companion at a projected separation of ∼40 AU that could account for the circum-binary disk warp. This light curve and model is similar to the model we proposed for WL 4 in previous work. Understanding these systems may lead to insights about the nature of stellar evolution and planetary formation, and provide valuable benchmarks for future theoretical modeling and near-and mid-infrared synoptic surveys of YSOs.

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Section: Discussionmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The identification of 93 day periodic photometric variability for YSO YLW 16A

Plavchan

Güth

Laohakunakorn

et al. 2013

A&A

Self Cite

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“…The spacings between periodic shocks in jets and outflows support quiescent intervals anywhere from 10 4 yr down to 10 yr, separating bursts with an unknown range of accretion rates (Devine et al 1997;Raga et al 2002;Arce et al 2013). Highcadence photometric surveys show luminosity variations at the 5-50% level on timescales of hours to weeks (Billot et al 2012;Stauffer et al 2014), though only some of that may be related to accretion variability (Morales-Calderón et al 2011;Rebull et al 2014). Despite the incomplete statistics, it appears that stronger accretion bursts occur less frequently than weaker ones.…”

Section: And For Fuormentioning

confidence: 96%

Chemical tracers of episodic accretion in low-mass protostars

Visser

Bergin

Jørgensen

2015

A&A

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Aims. Accretion rates in low-mass protostars can be highly variable in time. Each accretion burst is accompanied by a temporary increase in luminosity, heating up the circumstellar envelope and altering the chemical composition of the gas and dust. This paper aims to study such chemical effects and discusses the feasibility of using molecular spectroscopy as a tracer of episodic accretion rates and timescales. Methods. We simulate a strong accretion burst in a diverse sample of 25 spherical envelope models by increasing the luminosity to 100 times the observed value. Using a comprehensive gas-grain network, we follow the chemical evolution during the burst and for up to 10 5 yr after the system returns to quiescence. The resulting abundance profiles are fed into a line radiative transfer code to simulate rotational spectra of C 18 O, HCO + , H 13 CO + , and N 2 H + at a series of time steps. We compare these spectra to observations taken from the literature and to previously unpublished data of HCO + and N 2 H + 6−5 from the Herschel Space Observatory. Results. The bursts are strong enough to evaporate CO throughout the envelope, which in turn enhances the abundance of HCO + and reduces that of N 2 H + . After the burst, it takes 10 3 -10 4 yr for CO to refreeze and for HCO + and N 2 H + to return to normal. The H 2 O snowline expands outwards by a factor of ∼10 during the burst; afterwards, it contracts again on a timescale of 10 2 -10 3 yr. The chemical effects of the burst remain visible in the rotational spectra for as long as 10 5 yr after the burst has ended, highlighting the importance of considering luminosity variations when analyzing molecular line observations in protostars. The spherical models are currently not accurate enough to derive robust timescales from single-dish observations. As follow-up work, we suggest that the models be calibrated against spatially resolved observations in order to identify the best tracers to be used for statistically significant source samples.

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“…Using the 2MASS south telescope, Carpenter et al (2001Carpenter et al ( , 2002 performed widefield near infrared (NIR) variability studies of stars towards the Orion A and Chamaeleon I star-forming regions. More recently, Rice et al (2012) have monitored the dark cloud L 1003 in Cygnus OB7 at NIR wavelengths with UKIRT over a time span of 1.5 years, and Morales et al (2011Morales et al ( , 2012 collected multi-epoch, multi-color light curves of candidate members of the Orion nebular cluster region during their dedicated Warm Spitzer Exploration Science Program YSOVAR (complemented by UKIRT and CFHT data). Likewise, a comprehensive longterm (meanwhile spanning 8 yrs) monitoring campaign of NIR variability in a large sample of brown dwarfs and T Tauri stars has been carried out by Scholz and collaborators (Scholz et al 2009;Scholz 2012).…”

Section: Introductionmentioning

confidence: 99%

Near-infrared variability in the star-forming region RCW 38

Dörr

Chini

Haas

et al. 2013

A&A

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Aims. We want to study the content of young stellar objects in the RCW 38 cluster by means of multi-epoch variability studies. Methods. We performed a three-month near-infrared (NIR) monitoring campaign of the young cluster RCW 38 using the 80 cm IRIS telescope near Cerro Armazones, Chile. Variability data with a median sampling of 1 day was gathered for 1026 sources, while a total of 3433 sources in JHK could be studied in the co-added, deep images with a completeness limit of K < 15 mag. Results. We find that 139 sources were identified as variable with amplitudes above 10% in H and K, and 47% of these variables have been classified as candidate young stars by previous X-ray and mid-infrared studies. Although the majority of the variable sources show no K-excess, their high extinction and concentration towards the cluster center, together with their irregular variability behavior, suggest that they are also candidate young stellar objects. Most of them are likely low-mass sources with variability amplitudes typical of T Tauri stars. The majority of previously suggested OB candidates appear to be intermediate-mass pre-main sequence sources on the basis of their JHK properties. Conclusions. NIR variability is an efficient tool for detecting new, embedded, young stellar objects that have escaped previous X-ray and mid-infrared studies.

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Ysovar: The First Sensitive, Wide-Area, Mid-Infrared Photometric Monitoring of the Orion Nebula Cluster

Cited by 220 publications

References 42 publications

The identification of 93 day periodic photometric variability for YSO YLW 16A

The identification of 93 day periodic photometric variability for YSO YLW 16A

Chemical tracers of episodic accretion in low-mass protostars

Near-infrared variability in the star-forming region RCW 38

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