Disk Structure around the Class I Protostar L1489 IRS Revealed by ALMA: A Warped-disk System

Sai, Jinshi; Ohashi, Nagayoshi; Saigo, Kazuya; Matsumoto, Toshiro; Aso, Yusuke; Takakuwa, Shigehisa; Aikawa, Yuri; Kurose, Ippei; Yen, Hsi-Wei; Tomisaka, Kohji; Tomida, Kengo; Machida, Masahiro N.

doi:10.3847/1538-4357/ab8065

Cited by 36 publications

(79 citation statements)

References 92 publications

(144 reference statements)

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“…The current resolution does not resolve the inner 10au; hence, the reduction in CO emission is more extended. In IRAS04302, a similar offset of Sai et al (2020). The slight rise seen in C 18 O emission around ∼300 au to the southwest of the continuum peak is also visible in the C 17 O radial cut.…”

Section: O and H 2 Co Morphologymentioning

confidence: 60%

Temperature Structures of Embedded Disks: Young Disks in Taurus Are Warm

Hoff

Harsono

Tobin

et al. 2020

ApJ

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The chemical composition of gas and ice in disks around young stars sets the bulk composition of planets. In contrast to protoplanetary disks (Class II), young disks that are still embedded in their natal envelope (Class 0 and I) are predicted to be too warm for CO to freeze out, as has been confirmed observationally for L1527 IRS. To establish whether young disks are generally warmer than their more evolved counterparts, we observed five young (Class 0/I and I) disks in Taurus with the Atacama Large Millimeter/submillimeter Array, targeting2,1 , and CH 3 OH 5 K −4 K transitions at 0 48×0 31 resolution. The different freeze-out temperatures of these species allow us to derive a global temperature structure. C 17 O and H 2 CO are detected in all disks, with no signs of CO freeze-out in the inner ∼100 au and a CO abundance close to ∼10 −4 . The H 2 CO emission originates in the surface layers of the two edge-on disks, as witnessed by the especially beautiful V-shaped emission pattern in IRAS04302+2247. HDO and CH 3 OH are not detected, with column density upper limits more than 100 times lower than for hot cores. Young disks are thus found to be warmer than more evolved protoplanetary disks around solar analogs, with no CO freeze-out (or only in the outermost part of 100 au disks) or processing. However, they are not as warm as hot cores or disks around outbursting sources and therefore do not have a large gas-phase reservoir of complex molecules.

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Section: O and H 2 Co Morphologymentioning

confidence: 60%

Temperature Structures of Embedded Disks: Young Disks in Taurus Are Warm

Hoff

Harsono

Tobin

et al. 2020

ApJ

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“…Thus, dust evolution is unlikely a dominant mechanism in determining the disk size distribution observed in the millimeter continuum. In addition, in a few embedded Class 0 and I protostars, where the disk radii were measured with gas kinematics, the disk radii observed in the millimeter continuum are comparable to the dynamically measured disk radii within a factor of two (e.g., Ohashi et al 2014;Yen et al 2014;Aso et al 2015Aso et al , 2017Sai et al 2020). For a given protostar, the separation is defined as its distance to the protostar nearest to it.…”

Section: Potential Biases Due To Multiplicity and Evolutionmentioning

confidence: 54%

No impact of core-scale magnetic field, turbulence, or velocity gradient on sizes of protostellar disks in Orion A

Yen,

Zhao,

Koch

et al. 2021

Preprint

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We compared the sizes and fluxes of a sample of protostellar disks in Orion A measured with the ALMA 0.87 mm continuum data from the VANDAM survey with the physical properties of their ambient environments on the core scale of 0.6 pc estimated with the GBT GAS NH 3 and JCMT SCUPOL polarimetric data. We did not find any significant dependence of the disk radii and continuum fluxes on a single parameter on the core scale, such as the non-thermal line width, magnetic field orientation and strength, or magnitude and orientation of the velocity gradient. Among these parameters, we only found a positive correlation between the magnitude of the velocity gradient and the non-thermal line width. Thus, the observed velocity gradients are more likely related to turbulent motion but not large-scale rotation. Our results of no clear dependence of the disk radii on these parameters are more consistent with the expectation from non-ideal MHD simulations of disk formation in collapsing cores, where the disk size is self-regulated by magnetic braking and diffusion, compared to other simulations which only include turbulence and/or a magnetic field misaligned with the rotational axis. Therefore, our results could hint that the non-ideal MHD effects play a more important role in the disk formation. Nevertheless, we cannot exclude the influences on the observed disk size distribution by dynamical interaction in a stellar cluster or amounts of angular momentum on the core scale, which cannot be probed with the current data.

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“…The dynamical mass of L1489 IRS was also estimated to be ∼1.6 M (Yen et al 2014;Sai et al 2020), which is relatively larger than other protostars whose dynamical masses were es-timated (Murillo et al 2013;Harsono et al 2014;Chou et al 2014;Lee et al 2014;Aso et al 2015Aso et al , 2017. The systemic velocity of L1489 IRS was estimated from the Keplerian rotation to be 7.22 km s −1 (Sai et al 2020). We have adopted v LSR = 7.22 km s −1 for the systemic velocity of L1489 IRS in this paper.…”

Section: Introductionmentioning

confidence: 99%

“…Yen et al (2014) have identified a Keplerian disk with a radius of ∼700 au, which is the largest one identified around a Class I protostar so far, and two infalling flows accreting onto the disk surface based on their ALMA 12-m array observations in the C 18 O 2-1 emission at angular resolutions of ∼ 1 . Sai et al (2020) have reexamined the gas kinematics at an angular resolution about three times higher than that in Yen et al (2014), revealing that a Keplerian disk with a radius of ∼600 au is surrounded by an infalling envelope with a constant specific angular momentum. The dynamical mass of L1489 IRS was also estimated to be ∼1.6 M (Yen et al 2014;Sai et al 2020), which is relatively larger than other protostars whose dynamical masses were es-timated (Murillo et al 2013;Harsono et al 2014;Chou et al 2014;Lee et al 2014;Aso et al 2015Aso et al , 2017.…”

Section: Introductionmentioning

confidence: 99%

“…Sai et al (2020) have reexamined the gas kinematics at an angular resolution about three times higher than that in Yen et al (2014), revealing that a Keplerian disk with a radius of ∼600 au is surrounded by an infalling envelope with a constant specific angular momentum. The dynamical mass of L1489 IRS was also estimated to be ∼1.6 M (Yen et al 2014;Sai et al 2020), which is relatively larger than other protostars whose dynamical masses were es-timated (Murillo et al 2013;Harsono et al 2014;Chou et al 2014;Lee et al 2014;Aso et al 2015Aso et al , 2017. The systemic velocity of L1489 IRS was estimated from the Keplerian rotation to be 7.22 km s −1 (Sai et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Which Part of Dense Cores Feeds Material to Protostars?: The Case of L1489 IRS

Sai,

Ohashi,

Maury

et al. 2021

Preprint

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We have conducted mapping observations (∼ 2 ×2 ) of the Class I protostar L1489 IRS using the 7-m array of the Atacama Compact Array (ACA) and the IRAM-30m telescope in the C 18 O 2-1 emission to investigate the gas kinematics on 1000-10,000 au scales. The C 18 O emission shows a velocity gradient across the protostar in a direction almost perpendicular to the outflow. The radial profile of the peak velocity was measured from a C 18 O position-velocity diagram cut along the disk major axis. The measured peak velocity decreases with radius at a radii of ∼1400-2900 au, but increases slightly or is almost constant at radii of r 2900 au. Disk-and-envelope models were compared with the observations to understand the nature of the radial profile of the peak velocity. The measured peak velocities are best explained by a model where the specific angular momentum is constant within a radius of 2900 au but increases with radius outside 2900 au. We calculated the radial profile of the specific angular momentum from the measured peak velocities, and compared it to analytic models of core collapse. The analytic models reproduce well the observed radial profile of the specific angular momentum and suggest that material within a radius of ∼4000-6000 au in the initial dense core has accreted to the central protostar. Because dense cores are typically ∼10,000-20,000 au in radius, and as L1489 IRS is close to the end of mass accretion phase, our result suggests that only a fraction of a dense core eventually forms a star.

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Disk Structure around the Class I Protostar L1489 IRS Revealed by ALMA: A Warped-disk System

Cited by 36 publications

References 92 publications

Temperature Structures of Embedded Disks: Young Disks in Taurus Are Warm

Temperature Structures of Embedded Disks: Young Disks in Taurus Are Warm

No impact of core-scale magnetic field, turbulence, or velocity gradient on sizes of protostellar disks in Orion A

Which Part of Dense Cores Feeds Material to Protostars?: The Case of L1489 IRS

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