Exoplanets and Stellar Physics

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LATTE: Lightcurve Analysis Tool for Transiting Exoplanets

Journal of Open Source Software, 5(49), 2101,

Authors:

Nora L. Eisner, Chris J. Lintott and Suzanne Aigrain

Abstract:

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Pleiades or Not? Resolving the Status of the Lithium Rich M Dwarfs HHJ339 and HHJ430

(2020)

Authors:

John Stauffer, Davide Barrado, Trevor David, Luisa Rebull, Lynne Hillenbrand, Eric Mamajek, Rebecca Oppenheimer, Suzanne Aigrain, Herve Bouy, Jorge Lillo-Box
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Atmospheric compositions and observability of nitrogen-dominated ultra-short-period super-Earths

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 494:1 (2020) 1490-1506

Authors:

Mantas Zilinskas, Yamila Miguel, Paul Mollière, Shang-Min Tsai
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Planet Hunters TESS I: TOI 813, a subgiant hosting a transiting Saturn-sized planet on an 84-day orbit

Monthly Notices of the Royal Astronomical Society, Volume 494, Issue 1, May 2020, Pages 750–763,

Authors:

N L Eisner, O Barragán, S Aigrain, C Lintott, G Miller, N Zicher, T S Boyajian, C Briceño, E M Bryant, J L Christiansen, A D Feinstein, L M Flor-Torres, M Fridlund, D Gandolfi, J Gilbert, N Guerrero, J M Jenkins, K Jones, M H Kristiansen, A Vanderburg, N Law, A R López-Sánchez, A W Mann, E J Safron, M E Schwamb, K G Stassun, H P Osborn, J Wang, A Zic, C Ziegler, F Barnet, S J Bean, D M Bundy, Z Chetnik, J L Dawson, J Garstone, A G Stenner, M Huten, S Larish, L D Melanson, T Mitchell, C Moore, K Peltsch, D J Rogers, C Schuster, D S Smith, D J Simister, C Tanner, I Terentev, A Tsymbal

Abstract:

We report on the discovery and validation of TOI 813 b (TIC 55525572 b), a transiting exoplanet identified by citizen scientists in data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and the first planet discovered by the Planet Hunters TESS project. The host star is a bright (V = 10.3 mag) subgiant (⁠R⋆=1.94R⊙⁠, M⋆=1.32M⊙⁠). It was observed almost continuously by TESS during its first year of operations, during which time four individual transit events were detected. The candidate passed all the standard light curve-based vetting checks, and ground-based follow-up spectroscopy and speckle imaging enabled us to place an upper limit of 2MJup (99 per cent confidence) on the mass of the companion, and to statistically validate its planetary nature. Detailed modelling of the transits yields a period of 83.8911+0.0027−0.0031 d, a planet radius of 6.71 ± 0.38 R⊕ and a semimajor axis of 0.423+0.031−0.037 AU. The planet’s orbital period combined with the evolved nature of the host star places this object in a relatively underexplored region of parameter space. We estimate that TOI 813 b induces a reflex motion in its host star with a semi-amplitude of ∼6 m s−1, making this a promising system to measure the mass of a relatively long-period transiting planet.
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The spectral impact of magnetic activity on disc-integrated HARPS-N solar observations: exploring new activity indicators

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 494:3 (2020) 4279-4290

Authors:

Apg Thompson, Ca Watson, Rd Haywood, Jc Costes, E de Mooij, A Collier Cameron, X Dumusque, Df Phillips, Sh Saar, A Mortier, Tw Milbourne, S Aigrain, Hm Cegla, D Charbonneau, R Cosentino, A Ghedina, Dw Latham, M Lopez-Morales, G Micela, E Molinari, E Poretti, A Sozzetti, S Thompson, R Walsworth

Abstract:

© 2020 Oxford University Press. All rights reserved. Stellar activity is the major roadblock on the path to finding true Earth-analogue planets with the Doppler technique. Thus, identifying new indicators that better trace magnetic activity (i.e. faculae and spots) is crucial to aid in disentangling these signals from that of a planet's Doppler wobble. In this work, we investigate activity related features as seen in disc-integrated spectra from the HARPS-N solar telescope. We divide high-activity spectral echelle orders by low-activity master templates (as defined using both logR _ HK and images from the Solar Dynamics Observatory, SDO), creating 'relative spectra'.With resolved images of the surface of the Sun (via SDO), the faculae and spot filling factors can be calculated, giving a measure of activity independent of, and in addition to, logR ' HK.We find pseudo-emission (and pseudoabsorption) features in the relative spectra that are similar to those reported in our previous work on α Cen B. In α Cen B, the features are shown to correlate better to changes in faculae filling factor than spot filling factor. In this work, we more confidently identify changes in faculae coverage of the visible hemisphere of the Sun as the source of features produced in the relative spectra. Finally, we produce trailed spectra to observe the radial velocity component of the features, which show that the features move in a redward direction as one would expect when tracking active regions rotating on the surface of a star.
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