skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Constraining the disk masses of the class I binary protostar GV Tau

Abstract

We present new spatially resolved 1.3 mm imaging with CARMA of the GV Tau system. GV Tau is a Class I binary protostar system in the Taurus Molecular Cloud, the components of which are separated by 1.''2. Each protostar is surrounded by a protoplanetary disk, and the pair may be surrounded by a circumbinary envelope. We analyze the data using detailed radiative transfer modeling of the system. We create synthetic protostar model spectra, images, and visibilities and compare them with CARMA 1.3 mm visibilities, a Hubble Space Telescope near-infrared scattered light image, and broadband spectral energy distributions from the literature to study the disk masses and geometries of the GV Tau disks. We show that the protoplanetary disks around GV Tau fall near the lower end of estimates of the Minimum Mass Solar Nebula, and may have just enough mass to form giant planets. When added to the sample of Class I protostars from Eisner, we confirm that Class I protostars are on average more massive than their Class II counterparts. This suggests that substantial dust grain processing occurs between the Class I and Class II stages, and may help to explain why the Class II protostars do not appearmore » to have, on average, enough mass in their disks to form giant planets.« less

Authors:
;  [1]
  1. Steward Observatory, University of Arizona 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
Publication Date:
OSTI Identifier:
22365411
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 791; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; COMPARATIVE EVALUATIONS; DUSTS; ENERGY SPECTRA; MASS; PLANETS; PROTOPLANETS; PROTOSTARS; RADIANT HEAT TRANSFER; RESOLUTION; SIMULATION; SOLAR NEBULA; SPACE; TELESCOPES; VISIBILITY; VISIBLE RADIATION

Citation Formats

Sheehan, Patrick D., and Eisner, Josh A., E-mail: psheehan@email.arizona.edu. Constraining the disk masses of the class I binary protostar GV Tau. United States: N. p., 2014. Web. doi:10.1088/0004-637X/791/1/19.
Sheehan, Patrick D., & Eisner, Josh A., E-mail: psheehan@email.arizona.edu. Constraining the disk masses of the class I binary protostar GV Tau. United States. doi:10.1088/0004-637X/791/1/19.
Sheehan, Patrick D., and Eisner, Josh A., E-mail: psheehan@email.arizona.edu. Sun . "Constraining the disk masses of the class I binary protostar GV Tau". United States. doi:10.1088/0004-637X/791/1/19.
@article{osti_22365411,
title = {Constraining the disk masses of the class I binary protostar GV Tau},
author = {Sheehan, Patrick D. and Eisner, Josh A., E-mail: psheehan@email.arizona.edu},
abstractNote = {We present new spatially resolved 1.3 mm imaging with CARMA of the GV Tau system. GV Tau is a Class I binary protostar system in the Taurus Molecular Cloud, the components of which are separated by 1.''2. Each protostar is surrounded by a protoplanetary disk, and the pair may be surrounded by a circumbinary envelope. We analyze the data using detailed radiative transfer modeling of the system. We create synthetic protostar model spectra, images, and visibilities and compare them with CARMA 1.3 mm visibilities, a Hubble Space Telescope near-infrared scattered light image, and broadband spectral energy distributions from the literature to study the disk masses and geometries of the GV Tau disks. We show that the protoplanetary disks around GV Tau fall near the lower end of estimates of the Minimum Mass Solar Nebula, and may have just enough mass to form giant planets. When added to the sample of Class I protostars from Eisner, we confirm that Class I protostars are on average more massive than their Class II counterparts. This suggests that substantial dust grain processing occurs between the Class I and Class II stages, and may help to explain why the Class II protostars do not appear to have, on average, enough mass in their disks to form giant planets.},
doi = {10.1088/0004-637X/791/1/19},
journal = {Astrophysical Journal},
number = 1,
volume = 791,
place = {United States},
year = {Sun Aug 10 00:00:00 EDT 2014},
month = {Sun Aug 10 00:00:00 EDT 2014}
}
  • We present the results of observations toward a low-mass Class-0/I protostar [BHB2007] no. 11 (B59 no. 11) in the nearby (d = 130 pc) star-forming region Barnard 59 (B59), in the Pipe Nebula. We utilize the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope ({approx}22'' resolution), focusing on the CO(3-2), HCO{sup +}, H{sup 13}CO{sup +}(4-3), and 1.1 mm dust-continuum emission transitions. We also show Submillimeter Array (SMA) data with {approx}5'' resolution in {sup 12}CO, {sup 13}CO, C{sup 18}O(2-1), and 1.3 mm dust-continuum emission. From ASTE CO(3-2) observations, we found that B59 no. 11 is blowing a collimated outflow whose axismore » lies almost on the plane of the sky. The outflow traces well a cavity-like structure seen in the 1.1 mm dust-continuum emission. The results of SMA {sup 13}CO and C{sup 18}O(2-1) observations have revealed that a compact and elongated structure of dense gas is associated with B59 no. 11; the structure is oriented perpendicular to the outflow axis. There is a compact dust condensation with a size of 350 Multiplication-Sign 180 AU seen in the SMA 1.3 mm continuum map, and the direction of its major axis is almost the same as that of the dense gas elongation. The distributions of {sup 13}CO and C{sup 18}O emission also show velocity gradients along their major axes, which are thought to arise from the envelope/disk rotation. From detailed analysis of the SMA data, we infer that B59 no. 11 is surrounded by a Keplerian disk with a radius of less than 350 AU. In addition, the SMA CO(2-1) image shows a velocity gradient in the outflow in the same direction as that of the dense gas rotation. We suggest that this velocity gradient indicates rotation in the outflow.« less
  • We have conducted ALMA observations in the 1.3 mm continuum and {sup 12}CO (2-1), C{sup 18}O (2-1), and SO (5{sub 6}-4{sub 5}) lines toward L1489 IRS, a Class I protostar surrounded by a Keplerian disk and an infalling envelope. The Keplerian disk is clearly identified in the {sup 12}CO and C{sup 18}O emission, and its outer radius (∼700 AU) and mass (∼0.005 M {sub ☉}) are comparable to those of disks around T Tauri stars. The protostellar mass is estimated to be 1.6 M {sub ☉} with the inclination angle of 66°. In addition to the Keplerian disk, there aremore » blueshifted and redshifted off-axis protrusions seen in the C{sup 18}O emission pointing toward the north and the south, respectively, adjunct to the middle part of the Keplerian disk. The shape and kinematics of these protrusions can be interpreted as streams of infalling flows with a conserved angular momentum following parabolic trajectories toward the Keplerian disk, and the mass infalling rate is estimated to be ∼5 × 10{sup –7} M {sub ☉} yr{sup –1}. The specific angular momentum of the infalling flows (∼2.5 × 10{sup –3} km s{sup –1} pc) is comparable to that at the outer radius of the Keplerian disk (∼4.8 × 10{sup –3} km s{sup –1} pc). The SO emission is elongated along the disk major axis and exhibits a linear velocity gradient along the axis, which is interpreted to mean that the SO emission primarily traces a ring region in the flared Keplerian disk at radii of ∼250-390 AU. The local enhancement of the SO abundance in the ring region can be due to the accretion shocks at the centrifugal radius where the infalling flows fall onto the disk. Our ALMA observations unveiled both the Keplerian disk and the infalling gas onto the disk, and the disk can further grow by accreting material and angular momenta from the infalling gas.« less
  • T Tauri stars are low mass young stars that may serve as analogs to the early solar system. Observations of organic molecules in the protoplanetary disks surrounding T Tauri stars are important for characterizing the chemical and physical processes that lead to planet formation. Searches for undetected molecules, particularly in the inner, planet forming regions of these disks are important for testing protoplanetary disk chemical models and for understanding the evolution of volatiles through the star and planet formation process. We used NIRSPEC on Keck 2 to perform a high resolution (λ/Δλ ∼ 25,000) L-band survey of T Tauri starmore » GV Tau N. This object is one of two in which the simple organic molecules HCN and C{sub 2}H{sub 2} have been reported in absorption in the warm molecular layer of the protoplanetary disk. In this Letter, we report the first detection of methane, CH{sub 4}, in a protoplanetary disk. Specifically, we detected the ν{sub 3} band in absorption. We determined a rotational temperature of 750 ± 50 K and column density of (2.8 ± 0.2) × 10{sup 17} cm{sup –2}. Our results imply that CH{sub 4} originates in the warm molecular layer of the inner protoplanetary disk.« less
  • We have analyzed the HCO{sup +} (1–0) data of the Class I–II protostar, HL Tau, obtained from the Atacama Large Millimeter/submillimeter Array long baseline campaign. We generated the HCO{sup +} image cube at an angular resolution of ∼0.″07 (∼10 au) and performed azimuthal averaging on the image cube to enhance the signal-to-noise ratio and measure the radial profile of the HCO{sup +} integrated intensity. Two gaps at radii of ∼28 and ∼69 au and a central cavity are identified in the radial intensity profile. The inner HCO{sup +} gap is coincident with the millimeter continuum gap at a radius ofmore » 32 au. The outer HCO{sup +} gap is located at the millimeter continuum bright ring at a radius of 69 au and overlaps with the two millimeter continuum gaps at radii of 64 and 74 au. On the contrary, the presence of the central cavity is likely due to the high optical depth of the 3 mm continuum emission and not the depletion of the HCO{sup +} gas. We derived the HCO{sup +} column density profile from its intensity profile. From the column density profile, the FWHM widths of the inner and outer HCO{sup +} gaps are both estimated to be ∼14 au, and their depths are estimated to be ∼2.4 and ∼5.0. These results are consistent with the expectation from the gaps opened by forming (sub-)Jovian mass planets, while placing tight constraints on the theoretical models solely incorporating the variation of dust properties and grain sizes.« less
  • We present imaging observations at the 1.3 mm wavelength of Class I protostars in the Taurus star-forming region, obtained with the CARMA interferometer. Of an initial sample of 10 objects, we detected and imaged millimeter wavelength emission from 9. One of the nine is resolved into two sources and detailed analysis of this binary protostellar system is deferred to a future paper. For the remaining eight objects, we use the CARMA data to determine the basic morphology of the millimeter emission. Combining the millimeter data with 0.9 {mu}m images of scattered light, Spitzer Infrared Spectrograph spectra, and broadband spectral energymore » distributions (all from the literature), we attempt to determine the structure of the circumstellar material. We consider models including both circumstellar disks and envelopes, and constrain the masses (and other structural parameters) of each of these components. We show that the disk masses in our sample span a range from {approx}< 0.01 to {approx}> 0.1 M{sub Sun }. The disk masses for our sample are significantly higher than for samples of more evolved Class II objects. Thus, Class I disk masses probably provide a more accurate estimate of the initial mass budget for star and planet formation. However, the disk masses determined here are lower than required by theories of giant planet formation. The masses also appear too low for gravitational instability, which could lead to high mass accretion rates. Even in these Class I disks, substantial particle growth may have hidden much of the disk mass in hard-to-see larger bodies.« less