Browsing by Author "Canas, Caleb I."

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    Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey
    (2021) Beaton, Rachael L.; Oelkers, Ryan J.; Hayes, Christian R.; Covey, Kevin R.; Chojnowski, S. D.; De Lee, Nathan; Sobeck, Jennifer S.; Majewski, Steven R.; Cohen, Roger E.; Fernandez-Trincado, Jose; Longa-Pena, Penelope; O'Connell, Julia E.; Santana, Felipe A.; Stringfellow, Guy S.; Zasowski, Gail; Aerts, Conny; Anguiano, Borja; Bender, Chad; Canas, Caleb I.; Cunha, Katia; Donor, John; Fleming, Scott W.; Frinchaboy, Peter M.; Feuillet, Diane; Harding, Paul; Hasselquist, Sten; Holtzman, Jon A.; Johnson, Jennifer A.; Kollmeier, Juna A.; Kounkel, Marina; Mahadevan, Suvrath; Price-Whelan, Adrian. M.; Rojas-Arriagada, Alvaro; Roman-Zuniga, Carlos; Schlafly, Edward F.; Schultheis, Mathias; Shetrone, Matthew; Simon, Joshua D.; Stassun, Keivan G.; Stutz, Amelia M.; Tayar, Jamie; Teske, Johanna; Tkachenko, Andrew; Troup, Nicholas; Albareti, Franco D.; Bizyaev, Dmitry; Bovy, Jo; Burgasser, Adam J.; Comparat, Johan; Downes, Juan Jose; Geisler, Doug; Inno, Laura; Manchado, Arturo; Ness, Melissa K.; Pinsonneault, Marc H.; Prada, Francisco; Roman-Lopes, Alexandre; Simonian, Gregory V. A.; Smith, Verne V.; Yan, Renbin; Zamora, Olga
    The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing a chemodynamical mapping of the Milky Way. The targeting for APOGEE-2 is complex and has evolved with time. In this paper, we present the updates and additions to the initial targeting strategy for APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two implementation modes: (i) "Ancillary Science Programs" competitively awarded to Sloan Digital Sky Survey IV PIs through proposal calls in 2015 and 2017 for the pursuit of new scientific avenues outside the main survey, and (ii) an effective 1.5 yr expansion of the survey, known as the Bright Time Extension (BTX), made possible through accrued efficiency gains over the first years of the APOGEE-2N project. For the 23 distinct ancillary programs, we provide descriptions of the scientific aims, target selection, and how to identify these targets within the APOGEE-2 sample. The BTX permitted changes to the main survey strategy, the inclusion of new programs in response to scientific discoveries or to exploit major new data sets not available at the outset of the survey design, and expansions of existing programs to enhance their scientific success and reach. After describing the motivations, implementation, and assessment of these programs, we also leave a summary of lessons learned from nearly a decade of APOGEE-1 and APOGEE-2 survey operations. A companion paper, F. Santana et al. (submitted; AAS29036), provides a complementary presentation of targeting modifications relevant to APOGEE-2 operations in the Southern Hemisphere.
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    Gaia-4b and 5b: Radial Velocity Confirmation of Gaia Astrometric Orbital Solutions Reveal a Massive Planet and a Brown Dwarf Orbiting Low-mass Stars
    (IOP Publishing Ltd, 2025) Stefansson, Gudmundur; Mahadevan, Suvrath; Winn, Joshua N.; Marcussen, Marcus L.; Kanodia, Shubham; Albrecht, Simon; Fitzmaurice, Evan; Mikulskyte, One; Canas, Caleb I.; Espinoza Retamal, Juan Ignacio; Zwart, Yiri; Krolikowski, Daniel M.; Hotnisky, Andrew; Robertson, Paul; Alvarado-Montes, Jaime A.; Bender, Chad F.; Blake, Cullen H.; Callingham, J. R.; Cochran, William D.; Delamer, Megan; Diddams, Scott A.; Dong, Jiayin; Fernandes, Rachel B.; Giovinazzi, Mark R.; Halverson, Samuel; Libby-Roberts, Jessica; Logsdon, Sarah E.; Mcelwain, Michael W.; Ninan, Joe P.; Rajagopal, Jayadev; Reji, Varghese; Roy, Arpita; Schwab, Christian; Wright, Jason T.
    Gaia astrometry of nearby stars is precise enough to detect the tiny displacements induced by substellar companions, but radial velocity (RV) data are needed for definitive confirmation. Here we present RV follow-up observations of 28 M and K stars with candidate astrometric substellar companions, which led to the confirmation of two systems, Gaia-4b and Gaia-5b, identification of five systems that are single lined but require additional data to confirm as substellar companions, and the refutation of 21 systems as stellar binaries. Gaia-4b is a massive planet (M = 11.8 +/- 0.7 MJ) in a P = 571.3 +/- 1.4 day orbit with a projected semimajor axis a0 = 0.312 +/- 0.040 mas orbiting a 0.644 +/- 0.02M circle dot star. Gaia-5b is a brown dwarf (M = 20.9 +/- 0.5MJ) in a P = 358.62 +/- 0.20 days eccentric e = 0.6423 +/- 0.0026 orbit with a projected angular semimajor axis of a0 = 0.947 +/- 0.038 mas around a 0.34 +/- 0.03M circle dot star. Gaia-4b is one of the first exoplanets discovered via the astrometric technique, and is one of the most massive planets known to orbit a low-mass star.
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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.