adsabs/AstroCLIMB huggingface dataset:
Paper: Coincident Multimessenger Bursts from Eccentric Supermassive Binary Black Holes
Authors: Vikram Manikantan, Vasileios Paschalidis, Gabriele Bozzola
Figure caption: Contours of plasma magnetization (σ ≡ b2/2ρ0) on the x–z-plane at t/M = 4197.6. The BHs are at x/M ± 10, z/M = 0. Immediately below and above the BHs are regions of high plasma magnetization σ ∼ 100–101, which extend vertically to ∣z∣ > 200 M. To the left and right of the BHs is the CBD, which has lower plasma magnetization σ ∼ 10−3–10−5. The magnetic field (overplotted with directed white lines) is highly ordered above and below the BHs, indicating the jet regions.
Paper: Spatial Age Distribution of Classical Cepheids in Spiral Galaxies: The Cases of M31 and M33
Authors: Giulia De Somma, Marcella Marconi, Vincenzo Ripepi, Santi Cassisi, Roberto Molinaro, Ilaria Musella, Teresa Sicignano, Erasmo Trentin
Figure caption: Age gradients of CCs in M31 across four quadrants of the galaxy: 0°–90° (top right), 90°–180° (top left), 180°–270° (bottom left), and 270°–360° (bottom right). Each panel shows the average age of CCs as a function of galactocentric radius (in kiloparsecs), with linear fits overlaid performed with a fixed intercept at 40.6 Myr. The blue dots represent the mean ages of CCs in radial bins, while the red dashed lines indicate the best-fit linear regression models. For reference, the disk scale length of M31 has been estimated to be ∼5.5 kpc (J. Yin et al. 2009).
Paper: Constraints on Nonthermal Pressure at Galaxy Cluster Outskirts from a Joint SPT and XMM-Newton Analysis
Authors: Arnab Sarkar, Michael McDonald, Lindsey Bleem, Mark Bautz, Bradford A. Benson, Priyanka Chakraborty, Catherine E. Grant, Christine Jones, Florian Kéruzoré, Eric D. Miller, Scott Randall, Charles Romero, Taweewat Somboonpanyakul, Yuanyuan Su
Figure caption: Comparison of global projected temperatures within 0.15R500 < r < R200 of clusters in our sample, measured using spectral fitting with the projected temperatures within the same radial range from our X-ray + SZ joint fitting. Left: X-ray temperatures are measured using Chandra observations and are taken from I. Babyk et al. (2012; A2744), F. Menanteau et al. (2010; AS0520, AS0592), and B. J. Maughan et al. (2008; AS1063, 1ES 0657–56, RXCJ2032.2–4420). Right: X-ray temperatures are measured using XMM-Newton observations and are taken from L. Lovisari et al. (2020).
Paper: Spatial Age Distribution of Classical Cepheids in Spiral Galaxies: The Cases of M31 and M33
Authors: Giulia De Somma, Marcella Marconi, Vincenzo Ripepi, Santi Cassisi, Roberto Molinaro, Ilaria Musella, Teresa Sicignano, Erasmo Trentin
Figure caption: Density maps of CCs in M31 (top panels) and M33 (bottom panels). Left panels: spatial density distributions of CCs, smoothed using a Gaussian kernel density estimation. In M31, a well-defined ring structure (dashed line) is visible at ∼11 kpc, consistent with previous studies, and a newly identified inner ring (dashed line) at ∼7 kpc is also observed. Right panels: the same density maps shown in polar coordinates, highlighting ringlike structures in M31 (dotted curves) and their spatial distributions.
Paper: Spatial Age Distribution of Classical Cepheids in Spiral Galaxies: The Cases of M31 and M33
Authors: Giulia De Somma, Marcella Marconi, Vincenzo Ripepi, Santi Cassisi, Roberto Molinaro, Ilaria Musella, Teresa Sicignano, Erasmo Trentin
Figure caption: The predicted age distributions of CCs in the spiral galaxies M31 (left panel) and M33 (right panel), derived by applying the PAZ relation to selected samples of F-mode and FO-mode CCs. Left panel: blue, red, and green histograms show F-mode CCs with ML case A, F-mode CCs with ML case B, FO-mode CCs with ML case A in M31, respectively. Right panel: same as left panel but for M33. Note that different scales are used in the left and right panels to account for the significantly larger CC sample in M31 with respect to M33.
Paper: Spatial Age Distribution of Classical Cepheids in Spiral Galaxies: The Cases of M31 and M33
Authors: Giulia De Somma, Marcella Marconi, Vincenzo Ripepi, Santi Cassisi, Roberto Molinaro, Ilaria Musella, Teresa Sicignano, Erasmo Trentin
Figure caption: Upper panels: age maps of CCs in M31 from the PAZ relation, showing spatial age distribution for different pulsation modes and ML relations: (left) FO mode (canonical A), (center) F mode (canonical A), (right) F mode (noncanonical B). The color bar indicates age in Myr. Bottom panels: same as above for M33.
Paper: Spatial Age Distribution of Classical Cepheids in Spiral Galaxies: The Cases of M31 and M33
Authors: Giulia De Somma, Marcella Marconi, Vincenzo Ripepi, Santi Cassisi, Roberto Molinaro, Ilaria Musella, Teresa Sicignano, Erasmo Trentin
Figure caption: Residuals between observed and model-predicted average ages for CCs in each galactic quadrant, based on a linear fit with a fixed intercept of 40.6 Myr.
Paper: Constraints on Nonthermal Pressure at Galaxy Cluster Outskirts from a Joint SPT and XMM-Newton Analysis
Authors: Arnab Sarkar, Michael McDonald, Lindsey Bleem, Mark Bautz, Bradford A. Benson, Priyanka Chakraborty, Catherine E. Grant, Christine Jones, Florian Kéruzoré, Eric D. Miller, Scott Randall, Charles Romero, Taweewat Somboonpanyakul, Yuanyuan Su
Figure caption: Nonthermal pressure fraction of galaxy clusters in our sample as a function of centroid shift. Centroid shift values have been adopted from Z. S. Yuan et al. (2022). Higher centroid shift implies that a cluster is more dynamically active, which increases nonthermal pressure at cluster outskirts.
Paper: Spatial Age Distribution of Classical Cepheids in Spiral Galaxies: The Cases of M31 and M33
Authors: Giulia De Somma, Marcella Marconi, Vincenzo Ripepi, Santi Cassisi, Roberto Molinaro, Ilaria Musella, Teresa Sicignano, Erasmo Trentin
Figure caption: Global age gradient of CCs in M33 as a function of galactocentric radius (in kiloparsecs). Blue dots indicate the mean ages of CCs in radial bins, while the red dashed line represents the best-fit linear regression model. For reference, the disk scale length of M33 has been estimated to be ∼4.34 kpc (A. Smercina et al. 2023).
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: Example transitions of cyanocoronene recorded with the cavity-enhanced FTMW spectrometer. (a)–(c) Three example spectra that were recorded by averaging approximately 4500–10,000 gas pulses acquired at a 5 Hz repetition rate and a 1 μs excitation pulse. The lines are split due to Doppler doubling induced by the coaxial cavity–supersonic expansion geometry of the instrument. We also report the SNR of the recorded lines. (d)–(f) Orange lines indicate the fitted rest frequencies. Corresponding quantum numbers of the transitions, ﹩{J}_{{K}_{a}^{{\prime} },{K}_{c}^{{\prime} }}^{{\prime} }-J{{\prime\prime} }_{{K}_{a}^{\prime\prime} ,{K}_{c}^{\prime\prime} }﹩, are labeled. Closely overlapping Ka components are labeled with α = {0, 1}, β = {1, 2}, γ = {2, 3}, δ = {3, 4}.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: MESMER-simulated bimolecular rate coefficients leading to the formation of H and cyanocoronene from the reaction of CN with coronene with the CCT collision rate coefficient given as a solid blue curve; the estimated uncertainty in this is presented as the shaded region. The MESMER predictions including the loose complex on the entrance channel are given as yellow circles, and those neglecting this are given as red squares.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: Potential energy surfaces for the addition of CN to coronene at the DLPNO-CCSD/def2-TZVPP//ωB97X-D4/def2-TZVPP level with DLPNO-CCSD/def2-TZVPP//BP-86-D3(BJ)/def2-SVP level results presented in parentheses. The upper panel provides the surface where a loose entrance channel complex is linked to the formation of the adducts. In the lower panel, this complex is neglected with a barrierless approach forming the cyano-adduct.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: 1H NMR (top) and 13C NMR (bottom) spectrum of formylcoronene.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: Parameter covariances and marginalized posterior distributions for the MCMC fit of cyanocoronene. The 16th, 50th, and 84th confidence intervals (corresponding to ±1σ for a Gaussian posterior distribution) are depicted as vertical lines on the diagonal plots.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: 1H NMR spectrum of cyanocoronene.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: 1H NMR spectrum of formylcoronene-oxime.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: First seven members of the most thermodynamically favorable, high-temperature (P)AH polymerization route, adapted from S. Stein (1978) and D. M. Hudgins & L. J. Allamandola (1995). Note that this is not a reaction scheme. Those whose CN derivatives have been detected in TMC-1 are depicted in black with their substitution sites marked by asterisks. Those in gray have not (yet) been detected or searched for in TMC-1. See Section 6 for details.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: Comparison of the derived column densities of the cyclic hydrocarbon (H) population in TMC-1 vs. number of carbon atoms, NC. We distinguish between single and multiple cycles, pentagon-containing (PA)Hs, solely hexagon-containing (P)AHs, and their CN derivatives. Purple hexagons refer to pure benzenoid PAHs, and their column densities were estimated from their CN derivatives (see text and Appendix G for details). Black hexagons are pure, single benzenoid cycles (aromatic hydrocarbons, AHs). Light blue hexagons correspond to CN-substituted benzenoid (P)AHs; black and dark blue pentagons are pure and CN-substituted pentagonal (PA)Hs, respectively. Column density values and the references they were taken from are reported in Table F1.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: GOTHAM spectra smoothed with a 10-channel Hanning window to a resolution of 14 kHz (black) overlaid with the spectra of cyanocoronene (orange) simulated using the MCMC-derived parameters given in Table E2. Lines with SNR  > 3σ are marked with asterisks.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: Optimized geometry of cyanocoronene, C24H11CN, in its principal axis system spanned by the vectors a and b. The highly symmetric coronene has 12 identical carbon sites for CN substitution that all result in the same cyanocoronene. Its permanent electric dipole moment was calculated to be μa = 5.67 D and μb = 0.59 D.
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: (a) Velocity-stacked spectra and (b) matched-filter analysis results of cyanocoronene spectra in the GOTHAM data generated using the methodologies outlined in R. A. Loomis et al. (2021).
Paper: Discovery of the Seven-ring Polycyclic Aromatic Hydrocarbon Cyanocoronene (C24H11CN) in GOTHAM Observations of TMC-1
Authors: Gabi Wenzel, Siyuan Gong, Ci Xue, P. Bryan Changala, Martin S. Holdren, Thomas H. Speak, D. Archie Stewart, Zachary T. P. Fried, Reace H. J. Willis, Edwin A. Bergin, Andrew M. Burkhardt, Alex N. Byrne, Steven B. Charnley, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ilsa R. Cooke, Michael C. McCarthy, Anthony J. Remijan, Alison E. Wendlandt, Brett A. McGuire
Figure caption: Full synthesis route from coronene (C24H12) to cyanocoronene (C24H11CN).
Paper: Thermal Emission and Confirmation of the Frigid White Dwarf Exoplanet WD 1856+534 b
Authors: Mary Anne Limbach, Andrew Vanderburg, Ryan J. MacDonald, Kevin B. Stevenson, Sydney Jenkins, Simon Blouin, Emily Rauscher, Rachel Bowens-Rubin, Elena Gallo, James Mang, Caroline V. Morley, David K. Sing, Christopher O'Connor, Alexander Venner, Siyi Xu
Figure caption: Top left: model SED of the WD (dotted black line), a 190 K blackbody (dashed–dotted purple line), and a 200 K cloudless planet model (M. S. Marley et al. 2021; dashed–dotted blue line; the coldest model available); the legend applies to all three panels. Lines for the blended SEDs (WD + planet model) are shown in the same color as the planet-only models but as solid lines. Photometry from both archival Spitzer and the new MIRI observations are shown as red and black error bars, respectively. The error bars in the y-axis are the 1σ uncertainty, and the error bars in the x-axis represent the width of the photometric bandpasses. Right: a zoom-in on the SED in the region where an excess is detected. The MIRI photometry is inconsistent with the WD-only model and is consistent with WD + planet models. Bottom left: normalized residuals (%) between the measured photometry and modeled WD photometry show a significant mid-IR excess at the longer wavelengths due to the exoplanet.
Paper: Thermal Emission and Confirmation of the Frigid White Dwarf Exoplanet WD 1856+534 b
Authors: Mary Anne Limbach, Andrew Vanderburg, Ryan J. MacDonald, Kevin B. Stevenson, Sydney Jenkins, Simon Blouin, Emily Rauscher, Rachel Bowens-Rubin, Elena Gallo, James Mang, Caroline V. Morley, David K. Sing, Christopher O'Connor, Alexander Venner, Siyi Xu
Figure caption: IR excess of WD 1856 compared with excesses observed in WDs from the JWST MIRI MEOW survey, including the planet candidate around WD 0310-688 (M. A. Limbach et al. 2024a), which shows a similar excess at 18 μm to that of WD 1856 b. Note that the WD 1856 model is anchored to the measured NIRSpec spectrum. In the absence of a NIRSpec spectrum for the MEOW data, we instead anchor the data at 7.7 μm.
Paper: Thermal Emission and Confirmation of the Frigid White Dwarf Exoplanet WD 1856+534 b
Authors: Mary Anne Limbach, Andrew Vanderburg, Ryan J. MacDonald, Kevin B. Stevenson, Sydney Jenkins, Simon Blouin, Emily Rauscher, Rachel Bowens-Rubin, Elena Gallo, James Mang, Caroline V. Morley, David K. Sing, Christopher O'Connor, Alexander Venner, Siyi Xu
Figure caption: Top: blackbody fit to the measured planet–star flux ratio (top left) and the corresponding posterior distribution (top right). Bottom: atmospheric retrieval with POSEIDON on the measured photometry (bottom left) and the corresponding computed effective temperature posterior (bottom right). Both approaches constrain the planet’s brightness/effective temperature to ≈185 K.
Paper: Thermal Emission and Confirmation of the Frigid White Dwarf Exoplanet WD 1856+534 b
Authors: Mary Anne Limbach, Andrew Vanderburg, Ryan J. MacDonald, Kevin B. Stevenson, Sydney Jenkins, Simon Blouin, Emily Rauscher, Rachel Bowens-Rubin, Elena Gallo, James Mang, Caroline V. Morley, David K. Sing, Christopher O'Connor, Alexander Venner, Siyi Xu
Figure caption: False-color image of the WD 1856 system constructed using three JWST/MIRI imaging bands: F770W (7.7 μm, blue), F1500W (15 μm, green), and F1800W (18 μm, red). The FOV measures 74″ × 113″, corresponding to 1835 au  × 2802  at the system’s distance of 24.8 pc. The (blended) WD and planet are the bluish-white star at the center of the image. The two bright stars near the right-hand side of the FOV are mid–M dwarf companion stars to the WD, at a projected separation of 1030 au. Numerous colorful background stars and galaxies are visible throughout the image.
Paper: Thermal Emission and Confirmation of the Frigid White Dwarf Exoplanet WD 1856+534 b
Authors: Mary Anne Limbach, Andrew Vanderburg, Ryan J. MacDonald, Kevin B. Stevenson, Sydney Jenkins, Simon Blouin, Emily Rauscher, Rachel Bowens-Rubin, Elena Gallo, James Mang, Caroline V. Morley, David K. Sing, Christopher O'Connor, Alexander Venner, Siyi Xu
Figure caption: Planet radius (in Jupiter radii) vs. measured temperature of confirmed exoplanets (green circles) and FFPs (gray diamonds), solar system planets (purple squares), and WD 1856 b (yellow star). WD 1856 b bridges the temperature gap between Jupiter and exoplanets/FFPs with temperature measurements.
Paper: TOI-421 b: A Hot Sub-Neptune with a Haze-free, Low Mean Molecular Weight Atmosphere
Authors: Brian Davenport, Eliza M.-R. Kempton, Matthew C. Nixon, Jegug Ih, Drake Deming, Guangwei Fu, E. M. May, Jacob L. Bean, Peter Gao, Leslie Rogers, Matej Malik
Figure caption: Placing TOI-421 b in the context of the characterized sub-Neptune population. Left: amplitudes of the 1.4 μm transmission spectral feature in units of scale heights (AH) for sub-Neptune exoplanets observed with HST-WFC3 (gray points) and JWST NIRISS (red points). GJ 1214b is included (open gray point) but not used for fitting, consistent with J. Brande et al. (2024). Parabolic fits to the HST data only, JWST data only, and all planets vs. Teq are shown in blue, orange, and purple, respectively. In the latter case, for the three planets observed with both HST and JWST, we fit only the JWST values in place of those from HST. All plotted values for HST data (gray points) are from J. Brande et al. (2024). JWST values (red points) are from our own retrievals on the JWST spectra, with the exception of GJ 9827d from P. Roy et al. (2025, in preparation). In all cases, AH is calculated using the same methodology as in J. Brande et al. (2024). Right: planet size vs. equilibrium temperature for all JWST-observed sub-Neptunes (colored symbols) and planned JWST sub-Neptune observations (gray symbols). Symbol color indicates the effective temperature of the stellar host, and filled (open) circles indicate derived MMW values less than (greater than) 5 amu. For K2-18 b, the true MMW is unknown owing to the potential for water condensation in its cold atmosphere. TOI-421 b is unique among JWST-observed sub-Neptunes in having a high Teq, orbiting a G-type host star, and having a low-MMW atmosphere.