Browsing by Author "Cegla, Heather"

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    NEID Reveals That the Young Warm Neptune TOI-2076 b Has a Low Obliquity
    (2023) Frazier, Robert C.; Stefansson, Gudmundur; Mahadevan, Suvrath; Yee, Samuel W.; Canas, Caleb I.; Winn, Joshua N.; Luhn, Jacob; Dai, Fei; Doyle, Lauren; Cegla, Heather; Kanodia, Shubham; Robertson, Paul; Wisniewski, John; Bender, Chad F.; Dong, Jiayin; Gupta, Arvind F.; Halverson, Samuel; Hawley, Suzanne; Hebb, Leslie; Holcomb, Rae; Kowalski, Adam; Libby-Roberts, Jessica; Lin, Andrea S. J.; McElwain, Michael W.; Ninan, Joe P.; Petrovich, Cristobal; Roy, Arpita; Schwab, Christian; Terrien, Ryan C.; Wright, Jason T.
    TOI-2076 b is a sub-Neptune-sized planet (R = 2.39 + 0.10 R-circle plus) that transits a young (204 + 50 MYr) bright (V= 9.2) K-dwarf hosting a system of three transiting planets. Using spectroscopic observations obtained with the NEID spectrograph on the WIYN 3.5 m Telescope, we model the Rossiter-McLaughlin effect of TOI-2076 b, and derive a sky-projected obliquity of lambda = - 3 (-15) (+16) . Using the size of the star (R = 0.775 + 0.015 R-?), and the stellar 16 rotation period (P-rot = 7.27 + 0.23 days), we estimate an obliquity of y =18(-9) (+10) (psi < 34 degrees at 95% confidence), 10 demonstrating that TOI-2076 b is in a well-aligned orbit. Simultaneous diffuser-assisted photometry from the 3.5 m telescope at Apache Point Observatory rules out flares during the transit. TOI-2076 b joins a small but growing sample of young planets in compact multi-planet systems with well-aligned orbits, and is the fourth planet with an age ?300 Myr in a multi-transiting system with an obliquity measurement. The low obliquity of TOI-2076 b and the presence of transit timing variations in the system suggest the TOI-2076 system likely formed via convergent disk migration in an initially well-aligned disk.
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    The Warm Neptune GJ 3470b Has a Polar Orbit
    (2022) Stefansson, Gudmundur; Mahadevan, Suvrath; Petrovich, Cristobal; Winn, Joshua N.; Kanodia, Shubham; Millholland, Sarah C.; Maney, Marissa; Canas, Caleb, I; Wisniewski, John; Robertson, Paul; Ninan, Joe P.; Ford, Eric B.; Bender, Chad F.; Blake, Cullen H.; Cegla, Heather; Cochran, William D.; Diddams, Scott A.; Dong, Jiayin; Endl, Michael; Fredrick, Connor; Halverson, Samuel; Hearty, Fred; Hebb, Leslie; Hirano, Teruyuki; Lin, Andrea S. J.; Logsdon, Sarah E.; Lubar, Emily; McElwain, Michael W.; Metcalf, Andrew J.; Monson, Andrew; Rajagopal, Jayadev; Ramsey, Lawrence W.; Roy, Arpita; Schwab, Christian; Schweiker, Heidi; Terrien, Ryan C.; Wright, Jason T.
    The warm Neptune GJ 3470b transits a nearby (d = 29 pc) bright slowly rotating M1.5-dwarf star. Using spectroscopic observations during two transits with the newly commissioned NEID spectrometer on the WIYN 3.5 m Telescope at Kitt Peak Observatory, we model the classical Rossiter-McLaughlin effect, yielding a sky-projected obliquity of lambda = 98(-12)(+15)degrees and a v sin i = 0.85(-033)(+0.27) km s(-1). Leveraging information about the rotation period and size of the host star, our analysis yields a true obliquity of psi = 95(-8)(+9)degrees, revealing that GJ 3470b is on a polar orbit. Using radial velocities from HIRES, HARPS, and the Habitable-zone Planet Finder, we show that the data are compatible with a long-term radial velocity (RV) slope of gamma = -0.0022 +/- 0.0011 m s(-1) day(-1) over a baseline of 12.9 yr. If the RV slope is due to acceleration from another companion in the system, we show that such a companion is capable of explaining the polar and mildly eccentric orbit of GJ 3470b using two different secular excitation models. The existence of an outer companion can be further constrained with additional RV observations, Gaia astrometry, and future high-contrast imaging observations. Lastly, we show that tidal heating from GJ 3470b's mild eccentricity has most likely inflated the radius of GJ 3470b by a factor of similar to 1.5-1.7, which could help account for its evaporating atmosphere.