IPA: Class 0 Protostars Viewed in CO Emission Using JWST
Abstract
We investigate the bright CO fundamental emission in the central regions of five protostars in their primary mass assembly phase using new observations from JWST's Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI). CO line emission images and fluxes are extracted for a forest of $\sim$150 ro-vibrational transitions from two vibrational bands, $v=1-0$ and $v=2-1$. However, ${}^{13}$CO is undetected, indicating that ${}^{12}$CO emission is optically thin. We use H$_2$ emission lines to correct fluxes for extinction and then construct rotation diagrams for the CO lines with the highest spectral resolution and sensitivity to estimate rotational temperatures and numbers of CO molecules. Two distinct rotational temperature components are required for $v=1$ ($\sim600$ to 1000 K and 2000 to $\sim 10^4$ K), while one hotter component is required for $v=2$ ($\gtrsim 3500$ K). ${}^{13}$CO is depleted compared to the abundances found in the ISM, indicating selective UV photodissociation of ${}^{13}$CO; therefore, UV radiative pumping may explain the higher rotational temperatures in $v=2$. The average vibrational temperature is $\sim 1000$ K for our sources and is similar to the lowest rotational temperature components. Using the measured rotational and vibrational temperatures to infer a total number of CO molecules, we find that the total gas masses range from lower limits of $\sim10^{22}$ g for the lowest mass protostars to $\sim 10^{26}$ g for the highest mass protostars. Our gas mass lower limits are compatible with those in more evolved systems, which suggest the lowest rotational temperature component comes from the inner disk, scattered into our line of sight, but we also cannot exclude the contribution to the CO emission from disk winds for higher mass targets.
Authors 23
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Affiliation as printed
Department of Physics and Astronomy , Bausch & Lomb Hall , University of Rochester , Rochester , NY 14627 , USA
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The University of Texas at Austin
Affiliation as printed
Department of Astronomy , University of Texas at Austin , 1 University Station C1400 , Austin , TX 78712 , USA
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Tata Institute of Fundamental Research
Affiliation as printed
Department of Astronomy & Astrophysics Tata Institute of Fundamental Research , Homi Bhabha Rd , Colaba , Mumbai , Maharashtra , IN
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Institute of Astronomy and Astrophysics, Academia Sinica · Academia Sinica
Affiliation as printed
Academia Sinica Institute of Astronomy & Astrophysics , No. 1 Sec. 4 Roosevelt Rd. , Taipei 10617 , TW , R.O.C
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Leiden University · European Southern Observatory · Leiden Observatory
Affiliation as printed
European Southern Observatory , Karl-Schwarzschild-Strasse 2 , 85748 Garching , DE
Leiden Observatory , Leiden University , PO Box 9513 , 2300 RA Leiden , South Holland , NL
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University of Massachusetts Amherst
Affiliation as printed
Department of Astronomy , University of Massachusetts Amherst , 710 North Pleasant Street , Amherst , MA 01003 , USA
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Affiliation as printed
Ritter Astrophysical Research Center , Department of Physics and Astronomy , University of Toledo , Toledo , OH 43606 , USA
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Space Telescope Science Institute
Affiliation as printed
Space Telescope Science Institute , 3700 San Martin Drive , Baltimore , MD 21218 , USA
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Affiliation as printed
Department of Physics and Astronomy , Bausch & Lomb Hall , University of Rochester , Rochester , NY 14627 , USA
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Affiliation as printed
Ritter Astrophysical Research Center , Department of Physics and Astronomy , University of Toledo , Toledo , OH 43606 , USA
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Leiden University · Leiden Observatory
Affiliation as printed
Leiden Observatory , Leiden University , PO Box 9513 , 2300 RA Leiden , South Holland , NL
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Leiden University · Leiden Observatory
Affiliation as printed
Leiden Observatory , Leiden University , PO Box 9513 , 2300 RA Leiden , South Holland , NL
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Leiden University · Leiden Observatory
Affiliation as printed
Leiden Observatory , Leiden University , PO Box 9513 , 2300 RA Leiden , South Holland , NL
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Max Planck Institute for Astronomy
Affiliation as printed
Max Planck Institute for Astronomy , Heidelberg , Baden-Württemberg , DE
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Affiliation as printed
SKA Observatory , Jodrell Bank , Lower Withington , Macclesfield SK11 9FT , UK
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Affiliation as printed
Department of Astronomy , University of Michigan -Ann Arbor , 1085 S. University Ave , Ann Arbor , MI 48109 , USA
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Royal Observatory · UK Astronomy Technology Centre
Affiliation as printed
United Kingdom Astronomy Technology Centre , Royal Observatory Edinburgh , Blackford Hill , Edinburgh EH9 3HJ , GB
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Max Planck Institute for Astronomy · Friedrich Schiller University Jena
Affiliation as printed
Friedrich Schiller University , Jena , Thuringia , DE
Max Planck Institute for Astronomy , Heidelberg , Baden-Württemberg , DE
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University of Illinois Urbana-Champaign · National Radio Astronomy Observatory
Affiliation as printed
Department of Astronomy , University of Illinois , 1002 West Green St , Urbana , IL 61801 , USA
National Radio Astronomy Observatory , 520 Edgemont Rd. , Charlottesville , VA 22903 , USA
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Max Planck Institute for Extraterrestrial Physics
Affiliation as printed
Max Planck Institute for Extraterrestrial Physics , Gießenbachstraße 185748 Garching , DE
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National Radio Astronomy Observatory
Affiliation as printed
National Radio Astronomy Observatory , 520 Edgemont Rd. , Charlottesville , VA 22903 , USA
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Affiliation as printed
RIKEN Cluster for Pioneering Research , Wako-shi , Saitama , 351-0106 , JP
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