INITIATED JULY 2018: This is a list of molecules that have been found in protoplanetary/circumstellar disks, such as TW Hydrae (above left) and HL Tauri (above right). The list below also includes isotopomeric variants that have been detected in protoplanetary disks.

For background about chemistry in protoplanetary disks, see the archived presentation by Öberg et al. or the 2013 review paper by Henning & Semenov.

Initial detections are given first; a number of surveys are given at the bottom of the page.

INITIAL DETECTIONS
YEAR SPECIES CITATION SOURCE AND LINES
1993 13CO
carbon monoxide
A Rotating Gaseous Disk around the T Tauri Star GM Aurigae
D. W. Koerner, A. I. Sargent, and S. V. W. Beckwith. Icarus 106:2-10 (1993).
GM Aurigae
J = 2-1 (220.4 GHz)
1997 CN
cyano radical
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
1-0
2-1
1997 HCN
hydrogen cyanide
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
1-0
3-2
1997 HNC
hydrogen isocyanide
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
???
1997 CS
carbon monosulfide
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
3-2
5-4
1997 HCO+
protonated CO
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
1-0
3-2
1997 N2H+
protonated N2
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
1-0
1997 H2CO
formaldehyde
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
GG Tauri, DM Tauri
202-101
212-111
312-212
1997 C2H
ethynyl
Chemistry of protosolar-like nebulae: The molecular content of the DM Tau and GG Tau disks
A. Dutrey, S. Guilloteau, and M. Guélin. A&A 317:L55-L28 (1997).
DM Tauri
1-0
2001 CO
carbon monoxide
H2 and CO emisision from disks around T Tauri and Herbig Ae pre-main sequence stars and from debris disks around young stars: Warm and cold circumstellar gas
W. F. Thi, E. F. van Dishoeck, G. A. Blake, G. J. van Zadelhoff, J. Horn, E. E. Becklin, V. Mannings, A. I. Sargent, M. F. van den Ancker, A. Natta, and J. Kessler. ApJ 561:1074-1094 (2001).
Multiple sources
3-2
6-5
2003 DCO+
protonated CO
Detection of DCO+ in a circumstellar disk
E. F. van Dishoeck, W.-F. Thi, and G.-J. van Zadelhoff. A&A 400:L1-L4 (2003).
TW Hydrae
J = 5-4 (360.169 GHz)
2008 DCN
hydrogen cyanide
Resolving the Chemistry in the Disk of TW Hydrae. I. Deuterated Species
C. Qi, D. J. Wilner, Y. Aikawa, G. A. Blake, and M. R. Hogerheijde. ApJ 681:1396-1407.
TW Hydrae
J = 3-2 (217.23863 GHz)
2011 H2O
water
ASTROMOLECULE OF THE MONTH FOR DEC 2011
Detection of the Water Reservoir in a Forming Planetary System
M. R. Hogerheijde, E. A. Bergin, C. Brinch, L. I. Cleeves, J. K. J. Fogel, G. A. Blake, C. Dominik, D. C. Lis, G. Melnick, D. Neufeld, O. Panić, J. C. Pearson, L. Kristensen, U. A. Yıldız, and E. F. van Dishoeck. Science 334:338-340 (2011).
TW Hydrae
110-101 (ortho)
111-100 (para)
2011 H13CO+
protonated CO
The Ionization Fraction in the DM Tau Protoplanetary Disk
K. I. Öberg, C. Qi, D. J. Wilner, and S. M. Andrews. ApJ 743:152 (2011).
(first detection?)
DM Tau
J = 3-2 (260.255 GHz)
2012 HC3N
cyanoacetylene
ASTROMOLECULE OF THE MONTH FOR APR 2011
Chemistry in Disks. VII. First Detection of HC3N in Protoplanetary Disks
E. Chapillon, A. Dutrey, S. Guilloteau, V. Piétu, V. Wakelam, F. Hersant, F. Gueth, T. Henning, R. Launhardt, K. Schreyer, and D. Semenov. ApJ 756:58 (2018).
MWC 480...
(16-15) (145.560 GHz)
(12-11) (109.173 GHz)
(10-9) (90.978 GHz)
2013 HD
hydrogen
An old disk still capable of forming a planetary system
E. A. Bergin, L. I. Cleeves, U. Gorti, K. Zhang, G. A. Blake, J. D. Green, S. M. Andrews, N. J. Evans II, T. Henning, K. Öberg, K. Pontoppidan, C. Qi, C. Salyk, and E. F. van Dishoeck. Nature 493:644-646 (2013).
TW Hya
1-0 (~112 μm)
2013 SO
sulfur monoxide
A sensitive survey for 13CO, CN, H2CO, and SO in the disks of T Tauri and Herbig Ae stars
S. Guilloteau, E. Di Folco, A. Dutrey, M. Simon, N. Grosso, and V. Piétu. A&A 549, A92 (2013).
Chemistry in disks. X. The molecular content of protoplanetary disks in Taurus
S. Guilloteau, L. Reboussin, A. Dutrey, E. Chapillon, V. Wakelam, V. Piétu; E Di Folco, D. Semonov, and T. Henning. A&A 592:A125 (2016).
Multiple sources
54-43 (206.176062 GHz)
65-54 (251.825816 GHz)
67-56 (261.843756 GHz)
2013 c-C3H2
cyclo-
propenylidene

ASTROMOLECULE OF THE MONTH FOR AUG 2005
First Detection of c-C3H2 in a Circumstellar Disk
C. Qi, K. I. Öberg, D. J. Wilner, and K. A. Rosenfeld. ApJL 765:L14 (2013).
HD 163296
33,0-22,1 (216.279 GHz)
61,6-50,5/60,6-51,5 (217.822 GHz)
51,4-42,3 (217.940 GHz)
2015 CH3CN
methyl cyanide
ASTROMOLECULE OF THE MONTH FOR SEP 2008
The comet-like composition of a protoplanetary disk as revealed by complex cyanides
K. I. Öberg, V. V. Guzmán, K. Furuya, C. Qi, Y. Aikawa, S. M. Andrews, R. Loomis, and D. J. Wilner. Nature 520:198-200 (2015).
MWC 480
140-130 (257.5274 GHz)
141-131 (257.5224 GHz)
2015 N2D+
protonated nitrogen
Detection of N2D+ in a protoplanetary disk
J. Huang and K. I. Öber. ApJL 809:L26 (2015).
AS 209
3-2 (231.39868 MHz)
2015 H13CN
hydrogen cyanide
Cyanide photochemistry and nitrogen fractionation in the MWC 480 disk
V. V. Guzmán, K. I. Öberg, R. Loomis, and C. Qi. ApJ 814:53 (2015).
MWC 480
3-2 (259.0118 GHz)
2015 HC15N
hydrogen cyanide
Cyanide photochemistry and nitrogen fractionation in the MWC 480 disk
V. V. Guzmán, K. I. Öberg, R. Loomis, and C. Qi. ApJ 814:53 (2015).
MWC 480
3-2 (258.1571 GHz)
2016 CH3OH
methanol
ASTROMOLECULE OF THE MONTH FOR APR 2006
First Detection of Gas-phase Methanol in a Protoplanetary Disk
C. Walsh, R. A. Loomis, K. I. Öberg, M. Kama, M. L. R. van't Hoff, T. J. Millar, Y. Aikawa, E. Herbst, S. L. Widicus Weaver, and H. Nomura. ApJL 832:L10 (2016).
TW Hydrae
7 lines
2016 NH3
ammonia
ASTROMOLECULE OF THE MONTH FOR FEB 2010
First detection of gas-phase ammonia in a planet-forming disk. NH3, N2H+, and H2O in the disk around TW Hydrae
V. N. Salinas, M. R. Hogerheijde, E. A. Bergin, L. I. Cleeves, C. Brinch, G. A. Blake, D. C. Lis, G. J. Melnick, O. Panić, J. C. Pearson, L. Kristensen, U. A. YIJldIJz, and E. F. van Dishoeck. A&A 591:A122 (2016).
TW Hydrae
10-00 (572.49817 GHz)
2017 C15N
cyano radical
Direct evidence of multiple reservoirs of volatile nitrogen in a protosolar nebula analog
P. Hily-Blant, V. Magalhaes, J. Kastner, A. Faure, T. Forveille, and C. Qi. A&A 603:L6 (2017).
TW Hydrae
3-2 with hyperfine
2018 t-HCOOH
trans-formic acid
ASTROMOLECULE OF THE MONTH FOR MAY 2004
First Detection of the Simplest Organic Acid in a Protoplanetary Disk
C. Favre, D. Fedele, D. Semenov, S. Parfenov, C. Codella, C. Ceccarelli, E. A. Bergin, E. Chapillon, L. Testi, F. Hersant, B. Lefloch, F. Fontani, G. A. Blake, L. I. Cleeves, C. Qi, K. R. Schwarz, and V. Taquet. ApJL 862:L2 (2018).
TW Hydrae
6(1-6)5(1,5) (129 GHz)
2018 H2S
hydrogen sulfide
ASTROMOLECULE OF THE MONTH FOR NOV 2009
First detection of H2S in a protoplanetary disk. The dense GG Tauri A ring
N. T. Phuong, E. Chapillon, L. Majumdar, A. Dutrey, S. Guilloteau, V. Piétu, V. Wakelam, P. N. Diep, Y.-W. Tang, T. Beck, and J. Bary. A&A 616:L5 (2018).
GG Tauri
11,0-10,1
2019 13CS
carbon monosulfide
Sulfur Chemistry in Protoplanetary Disks: CS and H2CS
R. Le Gal, K. I. Öberg, R. A. Loomis, J. Pegues, and J. B. Bergner. ApJ 876:72 (2019).
LkCa 15  MWC 480
6-5
2019 C34S
carbon monosulfide
Sulfur Chemistry in Protoplanetary Disks: CS and H2CS
R. Le Gal, K. I. Öberg, R. A. Loomis, J. Pegues, and J. B. Bergner. ApJ 876:72 (2019).
LkCa 15
6-5
2019 H2CS
thioformaldehyde
Sulfur Chemistry in Protoplanetary Disks: CS and H2CS
R. Le Gal, K. I. Öberg, R. A. Loomis, J. Pegues, and J. B. Bergner. ApJ 876:72 (2019).
MWC 480
817-716
919-818
918-817
2019 13C17O
carbon monoxide
The First Detection of 13C17O in a Protoplanetary Disk: A Robust Tracer of Disk Gas Mass
A. S. Booth, C. Walsh, J. D. Ilee, S. Notsu, C. Qi, H. Nomura, and E. Akiyama. ApJL 882:L31 (2019).
HD 163296
blend of 14 hyperfine transitions of
J=3-2(321.851-321.852 GHz)
2022 HC18O+
protonated CO
Detection of HC18O+ in a Protoplanetary Disk: Exploring Oxygen Isotope Fractionation of CO
K. Furuya, T. Tsukagoshi, C. Qi, H. Nomura, L. I. Cleeves, S. Lee, and T. C. Yoshida. ApJ 926:148 (2022).
TW Hydrae
4-3 (340.6329780 GHz)
2022 CH3OCH3
dimethyl ether
A major asymmetric ice trap in a planet-forming disk - III. First detection of dimethyl ether
N. G. C. Brunken, A. S. Booth, M. Leemker, P. Nazari, N. van der Marel, and E. F. van Dishoeck. A&A 659:A29 (2022).
Oph IRS 48
various lines
2023 13CO2
carbon dioxide
MINDS. The Detection of 13CO2 with JWST-MIRI Indicates Abundant CO2 in a Protoplanetary Disk
S. L. Grant, E. F. van Dishoeck, B. Tabone, D. Gasman, T. Henning, I. Kamp, M. Güdel, P.-O. Lagage, G. Bettoni, G. Perotti, V. Christiaens, M. Samland et al. ApJL 947:L6 (2023).
GW Lup
Q-branch lines
2023 C6H6
benzene
A rich hydrocarbon chemistry and high C to O ratio in the inner disk around a very low-mass star
B. Tabone, G. Bettoni, E. F. van Dishoeck, A. M. Arabhavi, S. Grant, D. Gasman, T. Henning, I. Kamp, M. Güdel, P. O. Lagage, T. Ray, B. Vandenbussche et al. Nat Astron 7:805-814 (2023).
J160532
Q-branch lines
2023 C4H2
diacetylene
A rich hydrocarbon chemistry and high C to O ratio in the inner disk around a very low-mass star
B. Tabone, G. Bettoni, E. F. van Dishoeck, A. M. Arabhavi, S. Grant, D. Gasman, T. Henning, I. Kamp, M. Güdel, P. O. Lagage, T. Ray, B. Vandenbussche et al. Nat Astron 7:805-814 (2023).
J160532
Q-branch lines
2023 CH3+
methyl cation
ASTROMOLECULE OF THE MONTH FOR JUN 2024
Formation of the methyl cation by photochemistry in a protoplanetary disk
O. Berné, M.-A. Martin-Drumel, I. Schroetter, J. R. Goicoechea, U. Jacovella, B. Gans, E. Dartois, L. H. Coudert, E. Bergin, F. Alarcon, J. Cami, E. Roueff, J. H. Black, O. Asvany, E. Habart, E. Peeters, A. Canin, B. Trahin, C. Joblin, S. Schlemmer, S. Thorwirth, J. Cernicharo, M. Gerin, A. Tielens, M. Zannese et al. Nature 621:56-59 (2023).
d203-506
ro-vibrational structure of
v2 and v4 transitions

SURVEYS
YEAR SPECIES CITATION SOURCES
2010 H2O OH C2H2 HCN CO2 A Spitzer Survey of Mid-infrared Molecular Emission from Protoplanetary Disks. I. Detection Rates.
K. M. Pontoppidan, C. Salyk, G. A. Blake, R. Meijerink, J. S. Carr, and J. Najita. ApJ 720:887 (2010).
48 T Tauri stars
25 Herbig Ae/Be stars
2011 H2O OH C2H2 HCN CO2 A Spitzer Survey of Mid-infrared Molecular Emission from Protoplanetary Disks. II. Correlations and Local Thermal Equilibrium Models
C. Salyk, K. M. Pontoppidan, G. A. Blake, J. R. Najita, and J. S. Carr. ApJ 731:130 (2011).
48 T Tauri stars
25 Herbig Ae/Be stars
2020 H2CO An ALMA Survey of H2CO in Protoplanetary Disks
J. Pegues, K. I. Öberg, J. B. Bergner, R. A. Loomis, C. Qi, R. Le Gal, L. I. Cleeves, V. V. Guzmán, J. Huang, J. K. Jørgensen, S. M. Andrews, G. A. Blake, J. M. Carpenter, K. R. Schwarz, J. P. Williams, and D. J. Wilner. ApJ 890:142 (2020).
15 disks
2020 HCN Probing UV-sensitive Pathways for CN and HCN Formation in Protoplanetary Disks with the Hubble Space Telescope
N. Arulanantham, K. France, P. Cazzoletti, A. Miotello, C. F. Manara, P. C. Schneider, K. Hoadley, E. F. van Dishoeck, and H. M. Günther. AJ 159:168 (2020).
5 Lup and
14 Tau-Aur disks
2020 H2O HCN C2H2 CO2 Hints for Icy Pebble Migration Feeding an Oxygen-rich Chemistry in the Inner Planet-forming Region of Disks
A. Banzatti, I. Pascucci, A. D. Bosman, P. Pinilla, C. Salyk, G. J. Herczeg, K. M. Pontoppidan, I. Vazquez, A. Watkins, S. Krijt, N. Hendler, and F. Long. ApJ 903:124 (2020).
63 disks
2020 H2CS ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) - IV. Thioformaldehyde (H2CS) in protoplanetary discs: spatial distributions and binding energies
C. Codella, L. Podio, A. Garufi, J. Perrero, P. Ugliengo, D. Fedele, C. Favre, E. Bianchi, C. Ceccarelli, S. Mercimek, F. Bacciotti, K. L. J. Rygl, and L. Testi. A&A 644:A120 (2020).
5 Tau disks
2021 12CO 13CO C18O C2H H2CO HCN DCN An Atacama Large Millimeter/submillimeter Array Survey of Chemistry in Disks around M4-M5 Stars
J. Pegues, K. I. Öberg, J. B. Bergner, J. Huang, I. Pascucci, R. Teague, S. M. Andrews, . A. Bergin, L. I. Cleeves, V. V. Guzmán, F. Long, C. Qi, and D. J. Wilner. ApJ 911:150 (2021).
5 disks
2021 12CO 13CO C18O An ALMA Survey of Protoplanetary Disks in Lynds 1641
S. L. Grant, C. C. Espaillat, J. Wendeborn, J. J. Tobin, E. Macías, A. Rilinger, Á. Ribas, S. T. Megeath, W. J. Fischer, N. Calvet, and K. H. Kim. ApJ 913:123 (2021).
101 disks

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Updated 31 May 2024