Photometric and Spectroscopic Study of the EXor-like Eruptive Young Star Gaia19fct

Park, Sunkyung; Kóspál, Á.; Ábrahám, P.; Miera, Fernando Cruz-Sáenz de; Fiorellino, Eleonora; Siwak, M.; Nagy, Z.; Giannini, T.; Carini, R.; Szabó, Zs. M.; Lee, Jeong Eun; Lee, Jae-Joon; Vitali, F.; Kun, M.; Cseh, B.; Krezinger, Máté; Kriskovics, L.; Ordasi, A.; Pál, András; Szakáts, R.; Vida, K.; Vinkó, J.

doi:10.3847/1538-4357/aca01e

Cited by 12 publications

(5 citation statements)

References 108 publications

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“…We followed Tapia et al (2015) and used the mean distance to the Great Carina Nebula (NGC 3372) for V723 Car. The distance to iPTF 15afq was estimated by Park et al (2022) after comparing different distance estimates based on kinematics, Gaia parallax, and the distance to the CMa OB1 association, to which this object belongs. For Reipurth 50, Z CMa, GM Cha, V346 Nor, and OO Ser, we used distances compiled from the literature (Audard et al 2014, and references therein).…”

Section: Distancesmentioning

confidence: 99%

An APEX Study of Molecular Outflows in FUor-type Stars

Miera

Kóspál

Ábrahám

et al. 2023

ApJ

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The FU Orionis–type objects (FUors) are low-mass pre-main-sequence objects that go through a short-lived phase (∼100 yr) of increased mass accretion rate (from 10−8 to 10−4 M ⊙ yr−1). These eruptive young stars are in the early stages of stellar evolution and thus still deeply embedded in a massive envelope that feeds material to the circumstellar disk that is then accreted onto the star. Some FUors drive molecular outflows, i.e., low-velocity wide-angle magnetohydrodynamical winds, that inject energy and momentum back to the surrounding envelopes and help clear the material surrounding the young star. Here we present a 12CO (3–2), 13CO (3–2), and 12CO (4–3) survey of 20 FUor-type eruptive young stars observed with APEX. We use our 13CO (3–2) observations to measure the masses of the envelopes surrounding each FUor and find an agreement with the FUor evolutionary trend found from the 10 μm silicate feature. We find outflows in 11 FUors, calculate their masses and other kinematic properties, and compare these with those of outflows found around quiescent young stellar objects gathered from the literature. This comparison indicates that outflows in FUors are more massive than outflows in quiescent sources, and that FUor outflows have a higher-ratio outflow mass with respect to the envelope than the quiescent sample, indicating that the eruptive young stars have lower star-forming efficiencies. Finally, we find that the outflow forces in FUors are similar to those of quiescent young stellar objects, indicating that their accretion histories are similar or that the FUor outflows have lower velocities.

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Section: Distancesmentioning

confidence: 99%

An APEX Study of Molecular Outflows in FUor-type Stars

Miera

Kóspál

Ábrahám

et al. 2023

ApJ

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“…Indeed, just three sources have been claimed as bona fide FUors: Gaia17bpi (Hillenbrand et al 2018), Gaia18dvy (Szegedi-Elek et al 2020, and Gaia21elv (Nagy et al 2023). To these add four further sources that share properties of FUors and EXors-Gaia19ajj (Hillenbrand et al 2019), Gaia19bey (Hodapp et al 2020), Gaia21bty (Siwak et al 2023), and Gaia18cjb (Fiorellino et al 2024)-and four EXors: Gaia18dvz (ESO-Hα99; Hodapp et al 2019), Gaia20eae (Hankins et al 2020;Cruz-Sáenz de Miera et al 2022;Ghosh et al 2022), Gaia19fct (Miller et al 2015;Park et al 2022), and Gaia22dtk (Kuhn et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Gaia23bab: A New EXor

Giannini,

Schisano,

Nisini

et al. 2024

ApJ

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On 2023 March 6, the Gaia telescope alerted a 2 mag burst from Gaia23bab, a young stellar object in the Galactic plane. We observed Gaia23bab with the Large Binocular Telescope obtaining optical and near-infrared spectra close in time to the peak of the burst, and collected all public multiband photometry to reconstruct the historical light curve. The latter shows three bursts in 10 years (2013, 2017, and 2023), whose duration and amplitude are typical of EXor variables. We estimate that, due to the bursts, the mass accumulated on the star is about twice greater than if the source had remained quiescent for the same period of time. Photometric analysis indicates that Gaia23bab is a class II source with age ≲1 Myr, spectral type G3−K0, stellar luminosity ∼4.0 L ⊙, and mass ∼1.6 M ⊙. The optical/near-infrared spectrum is rich in emission lines. From the analysis of these lines we measured an accretion luminosity and mass accretion rate (L acc burst ∼ 3.7 L ⊙, M ̇ acc burst ∼ 2.0 × 10−7 M ⊙ yr−1) consistent with those of EXors. More generally, we derived the relationships between accretion and stellar parameters in a sample of EXors. We find that, when in burst, the accretion parameters become almost independent of the stellar parameters and that EXors, even in quiescence, are more efficient than classical T Tauri stars in assembling mass.

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“…The EXor class was defined by Herbig (1989) based on the properties of EX Lupi, and this class also consists of about a dozen objects (e.g. Audard et al 2014;Park et al 2022).…”

Section: Introductionmentioning

confidence: 99%

The Effelsberg survey of FU Orionis and EX Lupi objects

Szabó

Gong

Menten

et al. 2023

A&A

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Context. FU Orionis (FUor) and EX Lupi (EXor) type objects represent two small but rather spectacular groups of low-mass, young, eruptive stars. In both cases, outbursts of several magnitudes are observed, which are attributed to enhanced mass accretion from the circumstellar disc onto the central protostar. Although these objects are well studied at optical and near-infrared wavelengths, their host molecular environments are poorly explored because of the scarcity of systematic molecular line observations. Aims. We aim to carry out the first dedicated survey of the molecular environments of a large sample of FUors and EXors, observing a total of 51 sources, including some Gaia alerts, to study the ammonia (NH 3 ) emission in their host environments. Methods. We observed the ammonia (J, K)=(1,1), (2,2), and (3,3) inversion transitions at ∼23.7 GHz in position-switching mode using the Effelsberg 100-m radio telescope. For 19 of the 51 sources in our sample, we derived H 2 column densities and dust temperatures using archival Herschel SPIRE data at 250 µm, 300 µm, and 500 µm. Results. We detected the NH 3 (1,1) transition toward 28 sources and the (2,2) transition toward 12 sources, while the (3,3) transition was detected towards only two sources in our sample. We find kinetic temperatures between ∼12 K and 21 K, ammonia column densities from 5.2 × 10 13 cm −2 to 3.2 × 10 15 cm −2 , and fractional ammonia abundances with respect to H 2 from 4.7 × 10 −9 to 1.5 × 10 −7 . These results are comparable to those found in infrared dark clouds (IRDCs). Our kinematic analysis suggests that most of the eruptive stars in our sample reside in rather quiescent (sonic or transonic) host environments. Conclusions. Our NH 3 observations and analysis of the SPIRE dust-based H 2 column density maps confirm the presence of dense material towards seven sources in our sample; additional sources might also harbour dense gas based on their NH 2 (2,2) detections, potentially indicating an earlier phase than originally classified. Based on our results, we suggest that observations targeting additional molecular lines would help to refine the evolutionary classification of eruptive stars.

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Photometric and Spectroscopic Study of the EXor-like Eruptive Young Star Gaia19fct

Cited by 12 publications

References 108 publications

An APEX Study of Molecular Outflows in FUor-type Stars

An APEX Study of Molecular Outflows in FUor-type Stars

Gaia23bab: A New EXor

The Effelsberg survey of FU Orionis and EX Lupi objects

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