Browsing by Author "Pinto, Marcelo Tala"

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    HATS-38 b and WASP-139 b Join a Growing Group of Hot Neptunes on Polar Orbits
    (2024) Espinoza-Retamal, Juan I.; Stefansson, Gudmundur; Petrovich, Cristobal; Brahm, Rafael; Jordan, Andres; Sedaghati, Elyar; Lucero, Jennifer P.; Pinto, Marcelo Tala; Munoz, Diego J.; Boyle, Gavin; Leiva, Rodrigo; Suc, Vincent
    We constrain the sky-projected obliquities of two low-density hot Neptune planets, HATS-38 b and WASP-139 b, orbiting nearby G and K stars using Rossiter-McLaughlin (RM) observations with VLT/ESPRESSO, yielding lambda=-108(-16)(+11) deg and -85.6(-4.2)(+7.7) deg, respectively. To model the RM effect, we use a new publicly available code, ironman, which is capable of jointly fitting transit photometry, Keplerian radial velocities, and RM effects. WASP-139 b has a residual eccentricity e=0.103(-0.041)(+0.050) while HATS-38 b has an eccentricity of e=0.112(-0.070)(+0.072), which is compatible with a circular orbit given our data. Using the obliquity constraints, we show that they join a growing group of hot and low-density Neptunes on polar orbits. We use long-term radial velocities to rule out companions with masses similar to 0.3-50 M-J within similar to 10 au. We show that the orbital architectures of the two Neptunes can be explained with high-eccentricity migration from greater than or similar to 2 au driven by an unseen distant companion. If HATS-38b has no residual eccentricity, its polar and circular orbit can also be consistent with a primordial misalignment. Finally, we performed a hierarchical Bayesian modeling of the true obliquity distribution of Neptunes and found suggestive evidence for a higher preponderance of polar orbits of hot Neptunes compared to Jupiters. However, we note that the exact distribution is sensitive to the choice of priors, highlighting the need for additional obliquity measurements of Neptunes to robustly compare the hot Neptune obliquity distribution to Jupiters.
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    NGTS-11 b (TOI-1847 b): A Transiting Warm Saturn Recovered from a TESS Single-transit Event
    (2020) Gill, Samuel; Wheatley, Peter J.; Cooke, Benjamin F.; Jordan, Andres; Nielsen, Louise D.; Bayliss, Daniel; Anderson, David R.; Vines, Jose, I; Lendl, Monika; Acton, Jack S.; Armstrong, David J.; Bouchy, Francois; Brahm, Rafael; Bryant, Edward M.; Burleigh, Matthew R.; Casewell, Sarah L.; Eigmueller, Philipp; Espinoza, Nestor; Gillen, Edward; Goad, Michael R.; Grieves, Nolan; Gunther, Maximilian N.; Henning, Thomas; Hobson, Melissa J.; Hogan, Aleisha; Jenkins, James S.; McCormac, James; Moyano, Maximiliano; Osborn, Hugh P.; Pollacco, Don; Queloz, Didier; Rauer, Heike; Raynard, Liam; Rojas, Felipe; Sarkis, Paula; Smith, Alexis M. S.; Pinto, Marcelo Tala; Tilbrook, Rosanna H.; Udry, Stephane; Watson, Christopher A.; West, Richard G.
    We report the discovery of NGTS-11 b (=TOI-1847b), a transiting Saturn in a 35.46 day orbit around a mid K-type star (T-eff = 5050 +/- 80 K). We initially identified the system from a single-transit event in a TESS full-frame image light curve. Following 79 nights of photometric monitoring with an NGTS telescope, we observed a second full transit of NGTS-11 b approximately one year after the TESS single-transit event. The NGTS transit confirmed the parameters of the transit signal and restricted the orbital period to a set of 13 discrete periods. We combined our transit detections with precise radial-velocity measurements to determine the true orbital period and measure the mass of the planet. We find NGTS-11 b has a radius of 0.817 +/-(0.028)(0.032) R-Jup, a mass of 0.344 +/-(0.092)(0.073) M-Jup, and an equilibrium temperature of just 435 +/-(34)(32) K, making it one of the coolest known transiting gas giants. NGTS-11 b is the first exoplanet to be discovered after being initially identified as a TESS single-transit event, and its discovery highlights the power of intense photometric monitoring in recovering longer-period transiting exoplanets from single-transit events.
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    Three Warm Jupiters around Solar-analog Stars Detected with TESS
    (2023) Eberhardt, Jan; Hobson, Melissa J.; Henning, Thomas; Trifonov, Trifon; Brahm, Rafael; Espinoza, Nestor; Jordan, Andres; Thorngren, Daniel; Burn, Remo; Rojas, Felipe I.; Sarkis, Paula; Schlecker, Martin; Pinto, Marcelo Tala; Barkaoui, Khalid; Schwarz, Richard P.; Suarez, Olga; Guillot, Tristan; Triaud, Amaury H. M. J.; Gunther, Maximilian N.; Abe, Lyu; Boyle, Gavin; Leiva, Rodrigo; Suc, Vincent; Evans, Phil; Dunckel, Nick; Ziegler, Carl; Falk, Ben; Fong, William; Rudat, Alexander; Shporer, Avi; Striegel, Stephanie; Watanabe, David; Jenkins, Jon M.; Seager, Sara; Winn, Joshua N.
    We report the discovery and characterization of three giant exoplanets orbiting solar-analog stars, detected by the TESS space mission and confirmed through ground-based photometry and radial velocity measurements taken at La Silla observatory with FEROS. TOI-2373 b is a warm Jupiter orbiting its host star every similar to 13.3 days, and is one of the most massive known exoplanet with a precisely determined mass and radius around a star similar to the Sun, with an estimated mass of m(p) = 9.3(-0.2)(+0.2)Mjup and a radius of r(p) = 0.93(-0.2)(+0.2) jup. With a mean density of r = 14.4 1.0 g cm + 0.9 -3, TOI-2373 b is among the densest planets discovered so far. TOI-2416 b orbits its host star on a moderately eccentric orbit with a period of similar to 8.3 days and an eccentricity of e = 0.32 0.02 + 0.02. TOI-2416 b is more massive than Jupiter with m(p) = 3.0 +0.09 M 0.10 jup, however is significantly smaller with a radius of r(p) = 0.88 + 0.02 ,R 0.02 jup, leading to a high mean density of r = 5.4 0.3 g cm + 0.3 -3. TOI-2524 b is a warm Jupiter near the hot Jupiter transition region, orbiting its star every similar to 7.2 days on a circular orbit. It is less massive than Jupiter with a mass of m(p)=0.64- + 0.04 M 0.04 jup, and is consistent with an inflated radius of r(p)= 1.00- + 0.03 R 0.02 jup, leading to a low mean density of r = 0.79 0.08 g cm + 0.08 -3. The newly discovered exoplanets TOI-2373 b, TOI-2416 b, and TOI-2524 b have estimated equilibrium temperatures of 860 10 +10 K, 1080 10 +10 K, and 1100-20 +20 K, respectively, placing them in the sparsely populated transition zone between hot and warm Jupiters.
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    TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
    (2023) Hobson, Melissa J.; Trifonov, Trifon; Henning, Thomas; Jordan, Andres; Rojas, Felipe; Espinoza, Nestor; Brahm, Rafael; Eberhardt, Jan; Jones, Matias I.; Mekarnia, Djamel; Kossakowski, Diana; Schlecker, Martin; Pinto, Marcelo Tala; Torres Miranda, Pascal Jose; Abe, Lyu; Barkaoui, Khalid; Bendjoya, Philippe; Bouchy, Francois; Buttu, Marco; Carleo, Ilaria; Collins, Karen A.; Colon, Knicole D.; Crouzet, Nicolas; Dragomir, Diana; Dransfield, Georgina; Gasparetto, Thomas; Goeke, Robert F.; Guillot, Tristan; Guenther, Maximilian N.; Howard, Saburo; Jenkins, Jon M.; Korth, Judith; Latham, David W.; Lendl, Monika; Lissauer, Jack J.; Mann, Christopher R.; Mireles, Ismael; Ricker, George R.; Saesen, Sophie; Schwarz, Richard P.; Seager, S.; Sefako, Ramotholo; Shporer, Avi; Stockdale, Chris; Suarez, Olga; Tan, Thiam-Guan; J. Triaud, Amaury H. M.; Ulmer-Moll, Solene; Vanderspek, Roland; Winn, Joshua N.; Wohler, Bill; Zhou, George
    We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5 hr long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199 b has a 104.854-0.002+0.001day period, a mass of 0.17 +/- 0.02 M J, and a radius of 0.810 +/- 0.005 R J. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations (TTVs), pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the nontransiting companion TOI-199 c, which has a period of 273.69-0.22+0.26days and an estimated mass of 0.28-0.01+0.02MJ . This period places it within the conservative habitable zone.