Sukrit Ranjan

Interests

Research

Astrobiology, Earth, Early Earth, Exoplanets; Planetary Formation and Evolution, Origin of Life, Planetary Atmospheres, Photochemistry, Theoretical Astrophysics

Courses

Scholarly Contributions

Journals/Publications

• Bains, W., Pasek, M. A., Ranjan, S., Petkowski, J. J., Omran, A., & Seager, S. (2023). Large Uncertainties in the Thermodynamics of Phosphorus (III) Oxide (P4O6) Have Significant Implications for Phosphorus Species in Planetary Atmospheres. ACS Earth and Space Chemistry, 7(6), 1219-1226.
• Grant, D., Lewis, N. K., Wakeford, H. R., Batalha, N. E., Glidden, A., Goyal, J., Mullens, E., MacDonald, R. J., May, E. M., Seager, S., Stevenson, K. B., Valenti, J. A., Visscher, C., Alderson, L., Allen, N. H., Ca{\~nas}, C. I., Col{\'on}, K., Clampin, M., Espinoza, N., , Gressier, A., et al. (2023). JWST-TST DREAMS: Quartz Clouds in the Atmosphere of WASP-17b. \apjl, 956(2), L32.
• Initiative, T., Wit, J., Doyon, R., Rackham, B. V., Lim, O., Ducrot, E., Kreidberg, L., Benneke, B., Ribas, I., Berardo, D., Niraula, P., Iyer, A., Shapiro, A., Kostogryz, N., Witzke, V., Gillon, M., Agol, E., Meadows, V., Burgasser, A. J., , Owen, J. E., et al. (2023). A roadmap to the efficient and robust characterization of temperate terrestrial planet atmospheres with JWST. arXiv e-prints, arXiv:2310.15895.
• Ranjan, S., Abdelazim, K., Lozano, G. G., Mandal, S., Zhou, C. Y., Kufner, C. L., Todd, Z. R., Sahai, N., & Sasselov, D. D. (2023). Geochemical and Photochemical Constraints on S[IV] Concentrations in Natural Waters on Prebiotic Earth. AGU Advances, 4(6), e2023AV000926.
• Ranjan, S., Nayak, P. K., Pineda, J. S., & Narang, M. (2023). UV Spectral Characterization of Low-mass Stars with AstroSat UVIT for Exoplanet Applications: The Case Study of HIP 23309. \aj, 166(2), 70.
• Ranjan, S., Schwieterman, E. W., Leung, M., Harman, C. E., & Hu, R. (2023). The Importance of the Upper Atmosphere to CO/O$_2$ Runaway on Habitable Planets Orbiting Low-mass Stars. \apjl, 958(1), L15.
• Bains, W., Petkowski, J. J., Seager, S., Ranjan, S., Sousa-Silva, C., Rimmer, P. B., Zhan, Z., Greaves, J. S., & Richards, A. M. (2022). Venusian phosphine: a ‘wow!’signal in chemistry?. Phosphorus, Sulfur, and Silicon and the Related Elements, 197(5-6), 438--443.
• Bains, W., Shorttle, O., Ranjan, S., Rimmer, P. B., Petkowski, J. J., Greaves, J. S., & Seager, S. (2022). Constraints on the production of phosphine by Venusian volcanoes. Universe, 8(1), 54.
• Bains, W., Shorttle, O., Ranjan, S., Rimmer, P. B., Petkowski, J. J., Greaves, J. S., & Seager, S. (2022). Only extraordinary volcanism can explain the presence of parts per billion phosphine on Venus. Proceedings of the National Academy of Sciences, 119(7), e2121702119.
• Glidden, A., Seager, S., Huang, J., Petkowski, J. J., & Ranjan, S. (2022). Can Carbon Fractionation Provide Evidence for Aerial Biospheres in the Atmospheres of Temperate Sub-Neptunes?. The Astrophysical Journal, 930(1), 62.
• Greaves, J. S., Rimmer, P. B., Richards, A. M., Petkowski, J. J., Bains, W., Ranjan, S., Seager, S., Clements, D. L., Silva, C. S., & Fraser, H. J. (2022). Low levels of sulphur dioxide contamination of Venusian phosphine spectra. Monthly Notices of the Royal Astronomical Society, 514(2), 2994--3001.
• Huang, J., Seager, S., Petkowski, J. J., Ranjan, S., & Zhan, Z. (2022). Assessment of Ammonia as a Biosignature Gas in Exoplanet Atmospheres. Astrobiology, 22(2), 171--191.
• Huang, J., Seager, S., Petkowski, J. J., Zhan, Z., & Ranjan, S. (2022). Methanol—A Poor Biosignature Gas in Exoplanet Atmospheres. The Astrophysical Journal, 933(1), 6.
• Lin, Z., Seager, S., Ranjan, S., Kozakis, T., & Kaltenegger, L. (2022). H2-dominated Atmosphere as an Indicator of Second-generation Rocky White Dwarf Exoplanets. The Astrophysical Journal Letters, 925(1), L10.
• Ranjan, S., Kufner, C. L., Lozano, G. G., Todd, Z. R., Haseki, A., & Sasselov, D. D. (2022). UV Transmission in Natural Waters on Prebiotic Earth. Astrobiology, 22(3), 242--262.
• Ranjan, S., Seager, S., Zhan, Z., Koll, D. D., Bains, W., Petkowski, J. J., Huang, J., & Lin, Z. (2022). Photochemical Runaway in Exoplanet Atmospheres: Implications for Biosignatures. Astrophysical Journal, 930(2), 131.
• Zhan, Z., Huang, J., Seager, S., Petkowski, J. J., & Ranjan, S. (2022). Organic Carbonyls Are Poor Biosignature Gases in Exoplanet Atmospheres but May Generate Significant CO. The Astrophysical Journal, 930(2), 133.
• An, S., Ranjan, S., Yuan, K., Yang, X., & Skodje, R. T. (2021). The Role of the Three Body Photodissociation Channel of Water in the Evolution of Dioxygen in Astrophysical Applications. Physical Chemistry Chemical Physics.
• Bains, W., Petkowski, J. J., Seager, S., Ranjan, S., Sousa-Silva, C., Rimmer, P. B., Zhan, Z., Greaves, J. S., & Richards, A. M. (2021). Phosphine on Venus cannot be explained by conventional processes. Astrobiology, 21(10), 1277--1304.
• Greaves, J. S., Richards, A. M., Bains, W., Rimmer, P. B., Sagawa, H., Clements, D. L., Seager, S., Petkowski, J. J., Sousa-Silva, C., Ranjan, S., & others, . (2021). Addendum: Phosphine gas in the cloud deck of Venus. Nature Astronomy, 5(7), 726--728.
• Greaves, J. S., Richards, A. M., Bains, W., Rimmer, P. B., Sagawa, H., Clements, D. L., Seager, S., Petkowski, J. J., Sousa-Silva, C., Ranjan, S., & others, . (2021). Phosphine gas in the cloud decks of Venus. Nature Astronomy, 5(7), 655--664.
• Greaves, J. S., Richards, A., Bains, W., Rimmer, P. B., Clements, D. L., Seager, S., Petkowski, J. J., Sousa-Silva, C., Ranjan, S., & Fraser, H. J. (2021). Reply to: No evidence of phosphine in the atmosphere of Venus from independent analyses. Nature Astronomy, 5(7), 636--639.
• Rimmer, P. B., Ranjan, S., & Rugheimer, S. (2021). Life’s origins and the search for life on rocky exoplanets. Elements: An International Magazine of Mineralogy, Geochemistry, and Petrology, 17(4), 265--270.
• Seager, S., Petkowski, J. J., Gao, P., Bains, W., Bryan, N. C., Ranjan, S., & Greaves, J. (2021). The Venusian lower atmosphere haze as a depot for desiccated microbial life: A proposed life cycle for persistence of the Venusian aerial biosphere. Astrobiology, 21(10), 1206--1223.
• Zhan, Z., Seager, S., Petkowski, J. J., Sousa-Silva, C., Ranjan, S., Huang, J., & Bains, W. (2021). Assessment of isoprene as a possible biosignature gas in exoplanets with anoxic atmospheres. Astrobiology, 21(7), 765--792.
• G"unther, M. N., Zhan, Z., Seager, S., Rimmer, P. B., Ranjan, S., Stassun, K. G., Oelkers, R. J., Daylan, T., Newton, E., Kristiansen, M. H., & others, . (2020). Stellar flares from the first TESS data release: exploring a new sample of M dwarfs. The Astronomical Journal, 159(2), 60.
• Ranjan, S., Schwieterman, E. W., Harman, C., Fateev, A., Sousa-Silva, C., Seager, S., & Hu, R. (2020). Photochemistry of Anoxic Abiotic Habitable Planet Atmospheres: Impact of New H2O Cross Sections. The Astrophysical Journal, 896, 2.
• Sousa-Silva, C., Seager, S., Ranjan, S., Petkowski, J. J., Zhan, Z., Hu, R., & Bains, W. (2020). Phosphine as a biosignature gas in exoplanet atmospheres. Astrobiology, 20(2), 235--268.
• Todd, Z. R., Fahrenbach, A. C., Ranjan, S., Magnani, C. J., Szostak, J. W., & Sasselov, D. D. (2020). Ultraviolet-driven deamination of cytidine ribonucleotides under planetary conditions. Astrobiology, 20(7), 878--888.
• Ranjan, S., Todd, Z. R., Rimmer, P. B., Sasselov, D. D., & Babbin, A. R. (2019). Nitrogen oxide concentrations in natural waters on early Earth. Geochemistry, Geophysics, Geosystems, 20(4), 2021--2039.
• Ranjan, S., Todd, Z. R., Sutherland, J. D., & Sasselov, D. D. (2018). Sulfidic anion concentrations on early earth for surficial origins-of-life chemistry. Astrobiology, 18(8), 1023--1040.
• Todd, Z. R., Fahrenbach, A. C., Magnani, C. J., Ranjan, S., Bj"orkbom, A., Szostak, J. W., & Sasselov, D. D. (2018). Solvated-electron production using cyanocuprates is compatible with the UV-environment on a Hadean--Archaean Earth. Chemical Communications, 54(9), 1121--1124.
• Xu, J., Ritson, D. J., Ranjan, S., Todd, Z. R., Sasselov, D. D., & Sutherland, J. D. (2018). Photochemical reductive homologation of hydrogen cyanide using sulfite and ferrocyanide. Chemical Communications, 54(44), 5566--5569.
• Ranjan, S., & Sasselov, D. D. (2017). Constraints on the early terrestrial surface UV environment relevant to prebiotic chemistry. Astrobiology, 17(3), 169--204.
• Ranjan, S., Wordsworth, R., & Sasselov, D. D. (2017). Atmospheric constraints on the surface UV environment of Mars at 3.9 Ga relevant to prebiotic chemistry. Astrobiology, 17(8), 687--708.
• Ranjan, S., Wordsworth, R., & Sasselov, D. D. (2017). The surface UV environment on planets orbiting M dwarfs: implications for prebiotic chemistry and the need for experimental follow-up. The Astrophysical Journal, 843(2), 110.
• Ranjan, S., & Sasselov, D. D. (2016). Influence of the UV environment on the synthesis of prebiotic molecules. Astrobiology, 16(1), 68--88.
• Ranjan, S., Charbonneau, D., D'esert, J., Madhusudhan, N., Deming, D., Wilkins, A., & Mandell, A. M. (2014). Atmospheric characterization of five hot Jupiters with the wide field camera 3 on the Hubble space telescope. The Astrophysical Journal, 785(2), 148.
• Wilkins, A. N., Deming, D., Madhusudhan, N., Burrows, A., Knutson, H., McCullough, P., & Ranjan, S. (2014). The emergent 1.1--1.7 $mu$m spectrum of the exoplanet COROT-2b as measured using the Hubble Space Telescope. The Astrophysical Journal, 783(2), 113.
• Deming, D., Wilkins, A., McCullough, P., Burrows, A., Fortney, J. J., Agol, E., Dobbs-Dixon, I., Madhusudhan, N., Crouzet, N., Desert, J., & others, . (2013). Infrared transmission spectroscopy of the exoplanets HD 209458b and XO-1b using the Wide Field Camera-3 on the Hubble Space Telescope. The Astrophysical Journal, 774(2), 95.
• Nicolls, M. J., Heinselman, C. J., Hope, E. A., Ranjan, S., Kelley, M. C., & Kelly, J. D. (2007). Imaging of polar mesosphere summer echoes with the 450 MHz poker flat advanced modular incoherent scatter radar. Geophysical Research Letters, 34(20).

Proceedings Publications

• Cosgrove, R., Nicolls, M., Dahlgren, H., Ranjan, S., Sanchez, E., & Doe, R. (2010). Radar detection of a localized 1.4 Hz pulsation in auroral plasma, simultaneous with pulsating optical emissions, during a substorm. In Annales Geophysicae, 28.

Presentations

• Ranjan, S. (2023).

  A Re-Examination of Photochemical False Positives for O2 as a Biosignature Gas on Temperate Terrestrial Exoplanets

  . Origins 2023. Quito, Ecuador: International Society for the Study of the Origins of Life (ISSOL).
• Ranjan, S. (2023). Experimental Constraints for Improving Terrestrial Exoplanet Photochemical Models
  (ExCITE-PM). NASA Lab Astro PI Program Review. Washington, D. C.: National Aeronautics & Space Administration (NASA).
• Ranjan, S. (2023). Life in the Light: Photochemical Insights Towards Life as a Planetary Phenomenon. Alien Earths Origins Seminar.
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  Invited Seminar
• Ranjan, S. (2023). Life in the Light: Photochemical Insights Towards Life as a Planetary Phenomenon. CU Boulder Physical Chemistry/Chemical Physics Colloquium.
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  Invited Colloquium
• Ranjan, S. (2023). Life in the Light: Photochemical Insights Towards Life as a Planetary Phenomenon. JHU/StSci Joint Astrobiology Seminar. Baltimore, MD: Johns Hopkins University & Space Telescope Science Institute.
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  Invited Seminar
• Ranjan, S. (2023). Life in the Light: Photochemical Insights Towards Life as a Planetary Phenomenon. MIT Planetary Science Lunch Seminar.
• Ranjan, S. (2023). Life in the Light: Photochemical Insights Towards Life as a Planetary Phenomenon. Northern Arizona University Astronomy & Planetary Science Colloquium. Flagstaff, AZ: Northern Arizona University.
• Ranjan, S. (2023). Life in the Light: Photochemical Insights Towards Life as a Planetary Phenomenon. Penn State Astrobiology Hour. State College, PA: Pennsylvania State University.
• Ranjan, S. (2023). Photochemical Controls on Biosignature Gas Accumulation in Habitable Planet Atmospheres. Oxygen In Planetary Biospheres. Green Bank, WV: Green Bank Observatory.
• Ranjan, S. (2023). Photolytic Controls on Accumulation of Precursor Chemicals for Prebiotic Chemistry. BMSIS SeminarBlue Marble Space Institute of Science.
• Ranjan, S. (2023). Re-Assessment of CO/O2 Runaway in Temperate Terrestrial Planet Atmospheres. Alien Earths Team Meeting.
• Ranjan, S. (2023). Reduced Scope for Abiotic False Positives for Oxygen as a Biosignature Gas on Habitable Exoplanets. Steward Observatory Internal SymposiumSteward Observatory, UA.
• Ranjan, S. (2023). Sulfite In Natural Waters on Prebiotic Earth. NSF Workshop “Life in the Universe”. Cambridge, MA: National Science Foundation.
• Ranjan, S. (2023). The M-Dwarf Opportunity for Understanding Life as a Planetary Phenomenon. StSci Conference “Planetary Systems and the Origins of Life in the Era of JWST”. Baltimore, MD: Space Telescope Science Institute.
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  Invited Talk
• Ranjan, S. (2023). [S[IV]] In Natural Waters On Prebiotic Earth. LPL Science Conference (LPLSC).