About the nature of Mercer 14

Froebrich, D.; Ioannidis, G.

doi:10.1111/j.1365-2966.2011.19589.x

Cited by 10 publications

(19 citation statements)

References 27 publications

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“…C1, C2 in Appendix C in the online supplementary material. We can identify that V1490 Cyg exhibits a clear quasi-periodic behaviour for the broadband filters V, R c and I c , with a period of approximately 31.5 days, in agreement with Froebrich et al (2018a).…”

Section: The Quasi Periodic Light Curve Of V1490 Cygsupporting

confidence: 83%

A survey for variable young stars with small telescopes: II – mapping a protoplanetary disc with stable structures at 0.15 au

Evitts

Froebrich

Scholz

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The HOYS citizen science project conducts long-term, multifilter, high-cadence monitoring of large YSO samples with a wide variety of professional and amateur telescopes. We present the analysis of the light curve of V1490 Cyg in the Pelican Nebula. We show that colour terms in the diverse photometric data can be calibrated out to achieve a median photometric accuracy of 0.02 mag in broad-band filters, allowing detailed investigations into a variety of variability amplitudes over time-scales from hours to several years. Using Gaia DR2, we estimate the distance to the Pelican Nebula to be 870 $^{+70}_{-55}$ pc. V1490 Cyg is a quasi-periodic dipper with a period of 31.447 ± 0.011 d. The obscuring dust has homogeneous properties, and grains larger than those typical in the ISM. Larger variability on short time-scales is observed in U and Rc−H α, with U amplitudes reaching 3 mag on time-scales of hours, indicating that the source is accreting. The H α equivalent width and NIR/MIR colours place V1490 Cyg between CTTS/WTTS and transition disc objects. The material responsible for the dipping is located in a warped inner disc, about 0.15 au from the star. This mass reservoir can be filled and emptied on time-scales shorter than the period at a rate of up to 10−10 M⊙ yr−1, consistent with low levels of accretion in other T Tauri stars. Most likely, the warp at this separation from the star is induced by a protoplanet in the inner accretion disc. However, we cannot fully rule out the possibility of an AA Tau-like warp, or occultations by the Hill sphere around a forming planet.

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Section: The Quasi Periodic Light Curve Of V1490 Cygsupporting

confidence: 83%

A survey for variable young stars with small telescopes: II – mapping a protoplanetary disc with stable structures at 0.15 au

Evitts

Froebrich

Scholz

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…It has been used successfully by a number of authors e.g. in Foster et al (), Knude (), Froebrich & Ioannidis (). However, it is unclear if there are any systematic biases in applying this method.…”

Section: Discussionmentioning

confidence: 99%

“…They find that this extinction distance method agrees well with the maser parallax distances (within the errors) and is thus highly reliable. Similarly Froebrich & Ioannidis () have used this method successfully to determine the distance to the cluster Mercer 14.…”

Section: Discussionmentioning

confidence: 99%

“…We hence aim to characterize the general population of outflows from protostars and young stellar objects in an unbiased way. In order to have a representative sample of outflows which is free from selection effects, we are conducting an unbiased search for jets and outflows in the Galactic plane using the UKIRT Wide Field Infrared Survey for H 2 E-mail: gi8@kent.ac.uk (GI); df@star.kent.ac.uk (DF) (UWISH2; Froebrich et al 2011). The sample of outflows from this survey will allow us to perform a statistical investigation of their properties and to address some of the open questions in the field such as follows.…”

Section: Introductionmentioning

confidence: 99%

“…In particular we investigate the area 18 • < l < 30 • , −1.5 • < b < +1.5 • which approximately covers 33 square degrees. In Ioannidis & Froebrich (2012, hereafter Paper I), we presented the data (also discussed in Froebrich et al 2011) and discussed our detection method of jets/outflows and their potential driving sources. We did increase the sample of known molecular hydrogen emission-line objects (MHOs) 15-fold and investigated their basic properties such as fluxes, apparent projected lengths and spatial distribution.…”

Section: Introductionmentioning

confidence: 99%

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YSO jets in the Galactic plane from UWISH2 - II. Outflow luminosity and length distributions in Serpens and Aquila

Ioannidis

Froebrich

2012

Monthly Notices of the Royal Astronomical Society

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Jets and outflows accompany the mass accretion process in protostars and young stellar objects. Using a large and unbiased sample, they can be used to study statistically the local feedback they provide and the typical mass accretion history. Here we analyse such a sample of molecular hydrogen emission‐line objects in the Serpens and Aquila part of the Galactic plane. Distances are measured by foreground star counts with an accuracy of 25 per cent. The resulting spacial distribution and outflow luminosities indicate that our objects sample the formation of intermediate‐mass objects. The outflows are unable to provide a sizeable fraction of energy and momentum to support, even locally, the turbulence levels in their surrounding molecular clouds. The fraction of parsec scale flows is one quarter and the typical dynamical jet age of the order of 104 yr. Groups of emission knots are ejected every 103 yr. This might indicate that low‐level accretion rate fluctuations and not FU‐Ori‐type events are responsible for the episodic ejection of material. Better observational estimates of the FU‐Ori duty cycle are needed.

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Unveiling the substructure of the massive clump AGAL G035.1330−00.7450

Ortega

Marinelli

Isequilla

et al. 2022

A&A

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Context. It is known that high-mass stars form as the result of the fragmentation of massive molecular clumps. However, it is not clear whether this fragmentation gives rise to cores that are massive enough to directly form high-mass stars, or if leads to cores of low and intermediate masses that generate high-mass stars by acquiring material from their environment. Aims. Detailed studies of massive clumps at the early stage of star formation are needed to collect observational evidence that sheds light on the fragmentation processes from clump to core scales. The infrared-quiet massive clump AGAL G035.1330−00.7450 (AGAL35) located at a distance of 2.1 kpc is a promising object for studying the fragmentation and the star formation activity at early stages. Methods. Using millimeter observations of continuum and molecular lines obtained from the Atacama Large Millimeter Array database at Bands 6 and 7, we studied the substructure of the source AGAL35. The angular resolution of the data at Band 7 is about 0.′′7, which allowed us to resolve structures of about 0.007 pc (~1500 au). Results. The continuum emission at Bands 6 and 7 shows that AGAL35 harbors four dust cores, labeled C1 to C4, with masses lower than 3 M⊙. Cores C3 and C4 exhibit well-collimated, young, and low-mass molecular outflows related to molecular hydrogen emission-line objects that were previously detected. Cores C1 and C2 present CH3CN J = 13–12 emission, from which we derive rotational temperatures of about 180 and 100 K, respectively. These temperatures allow us to estimate masses of about 1.4 and 0.9 M⊙ for C1 and C2, respectively, which are about an order of magnitude lower than those estimated in previous works and agree with the Jeans mass of this clump. In particular, the moment 1 map of CH3CN emission suggests the presence of a rotating disk towards C1, which is confirmed by the CH3OH and CH3OCHO (20–19) emissions. On the other hand, the CN N = 2–1 emission shows a clumpy and filamentary structure that seems to connect all the cores. These filaments might be tracing the remnant gas of the fragmentation processes taking place within the massive clump AGAL35 or the gas that is being transported toward the cores, which would imply a competitive accretion scenario. Conclusions. The massive clump AGAL35 harbors four low- to intermediate-mass cores with masses lower than 3 M⊙, which is about an order of magnitude smaller than the masses estimated in previous works. This study shows that in addition to the importance of high-resolution and sensitivity observations for a complete detection of all fragments, it is very important to accurately determine the temperature of these cores for a correct mass estimation. Finally, although no high-mass cores were detected toward AGAL35, the filamentary structure connecting all the cores means that high-mass stars might form through the competitive accretion mechanism.

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About the nature of Mercer 14

Cited by 10 publications

References 27 publications

A survey for variable young stars with small telescopes: II – mapping a protoplanetary disc with stable structures at 0.15 au

A survey for variable young stars with small telescopes: II – mapping a protoplanetary disc with stable structures at 0.15 au

YSO jets in the Galactic plane from UWISH2 - II. Outflow luminosity and length distributions in Serpens and Aquila

Unveiling the substructure of the massive clump AGAL G035.1330−00.7450

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