333.01 — Endeavours towards precise M-dwarf properties: Activity robust multi-line modeling in the visual and near-infrared
Vera Maria Passegger1; Andreas Schweitzer1; Denis Shulyak2; Evangelos Nagel1; Peter H. Hauschildt1;
Ansgar Reiners3; Pedro J. Amado4; José A. Caballero5;
Miriam Cortés-Contreras5; Alejandro J. Domínguez-
Fernández6; David Montes6; Andreas Quirrenbach7;
Ignasi Ribas8,9
1 Hamburg Observatory (Hamburg, Germany)
Germany)
3 Institute for Astrophysics, Georg-August-University Goettingen (Goettingen, Germany)
4 Instituto de Astrofísica de Andalucía (Granada, Spain) 5 Centro de Astrobiología (Madrid, Spain)
6 Universidad Complutense de Madrid (Madrid, Spain) 7 Landessternwarte, U Heidelberg (Heidelberg, Germany) 8 Institut de Ciències de l’Espai (Barcelona, Spain)
9 Institut d’Estudis Espacials de Catalunya (Barcelona, Spain) A precise characterisation of planet-hosting stars is very important to derive and constrain the physical properties of orbiting planets. The CARMENES in- strument, which is searching for habitable planets around M dwarfs, provides us with high-resolution spectra in the visual (0.52–0.96 μm) and near- infrared wavelength range (0.96–1.71 μm). We fit the most recent PHOENIX-SESAM stellar atmosphere models simultaneously to both wavelength ranges to determine effective temperature, surface gravity, and metallicity for 282 M dwarfs. With these tem- peratures we also derive stellar masses and radii us- ing luminosities and Gaia DR2 parallaxes. Although stellar activity is widely unconsidered in stellar pa- rameter determination, we show the importance of taking into account this property by carefully select- ing magnetically insensitive lines, especially for the near-infrared wavelength range. For the first time, we directly compare stellar parameters such as ef- fective temperature, surface gravity, and metallic- ity derived from multiple wavelength ranges for the same spectra. We recommend using a combination of the visual and near-infrared wavelength ranges for parameter determination in order to maximise the amount of spectral information and minimise possi- ble effects due to model imperfections.
333.02 — Optical/Near-IR Microwave Kinetic In- ductance Detector-based Integral Field Spectro- graphs for High-Contrast Observations
Isabel Lipartito1; Benjamin A. Mazin1; Alexander B. Walter1; Clinton Bockstiegel1; Neelay Fruitwala1; Seth Meeker2; Paul Szypryt4; Nicholas Zobrist1; Gregoire Coiffard1; Sarah Steiger1; Noah Swimmer1; Jennifer Smith1; John I. Bailey1; Kristina Davis1; Henry Ru- pert Dodkins1; Olivier Guyon3,5; Nemanja Jovanovic6; Julien Lozi3; Ananya Sahoo3; Sebastien Vievard3; Dim-
itri Mawet6; Michael Bottom2; Clarissa Rizzo1
1 Physics, University of California, Santa Barbara (Santa Barbara, California, United States)
2 Jet Propulsion Laboratory (Pasadena, California, United States) 3 National Astronomical Observatory of Japan (Hilo, Hawaii, United States)
4 National Institute of Standards and Technology (Boulder, Col- orado, United States)
5 College of Optical Sciences, University of Arizona (Tucson, Ari- zona, United States)
6 California Institute of Technology (Pasadena, California, United States)
I will present an overview of the high-contrast imaging techniques achievable with Microwave Ki- netic Inductance Detector (MKID)-based instru- ments. Optical/Near-IR MKIDs are low noise detec- tors which can resolve both the energy and arrival time of individual photons, returning microsecond- accurate time-tagged photon lists. These lists allow for post-processing techniques that take full advan- tage of photon spectral and arrival time information, such as photon-counting Stochastic Speckle Discrim- ination (SSD), a technique which enables direct ob- servations of exoplanets at small separations from their host star, and Spectral Differential Imaging (SDI), a technique which exploits the chromatic be- havior of speckles to model the stellar Point-Spread Function (PSF). These techniques enable the subtrac- tion of the speckle background approaching the pho- ton noise limit. Active feedback techniques using the MKIDs as a focal plane wavefront sensor promise to further improve instrumental sensitivity. I will also present results from the MKID Exoplanet Cam- era (MEC). MEC is a 20,440 pixel MKID infrared camera that interfaces with the SCExAO planet find- ing instrument on the Subaru Telescope at Mauna Kea. MEC received first light in June 2018 and has been used to image young massive planets and de- bris disks.
333.03 — Capturing the Now — the AAS Oral His- tory Project
Jarita Holbrook1
1 Physics & Astronomy, University of the Western Cape (Belliville, Western Cape, South Africa)
The Oral History Project of the American Astronom- ical Society is in its sixth year. It is part of the ac- tivities of the Historical Astronomy Division. What is an oral history? Oral histories are interviews with individuals that are meant to capture some aspect of their, if not their entire, life. For the AAS project, we spend up to two hours with each person gath- ering background information, noting career moves, highlighting mentors, but also touching on current issues relevant to our community such as diversity, sexual harassment, data science, queue observing, tenure, and getting individual recognition for collab- orative research. We have interviewed over 150 sci-
entists, technicians, family members, and STEM sup- port staff. Some of these interviews can be found on the AIP archive of oral history interviews. The AAS Oral History Project is unique in that we in- terview anyone who volunteers to be interviewed: You do not need to be old and famous (like Doug Lin, but we do want to interview him, too!). Our interviews include undergraduates to emerita. The poster shares the full list of our interviewees and some of our preliminary analysis of trends. Finally, if you would like to be interviewed contact Jarita (jhol- [email protected]).
333.04 — A Fresh Look at Red Giant Planet Hosts Using TESS: A Study of Stellar Mass and Surface Gravity
Joleen Carlberg1; Doug Branton1; Jeff Valenti1
1 Space Telescope Science Institute (Baltimore, Maryland, United States)
A detailed understanding of even the most basic parameters of planetary systems requires accurate knowledge of the host star’s bulk properties. His- torically, measuring accurate masses for field red gi- ant stars has been especially difficult because stars of a wide range of masses evolve through similar parameter space on the Hertzsprung Russell dia- gram, sometimes passing through the same phase space multiple times. For a given luminosity and temperature, the star’s surface gravity must also be known. Until recently, surface gravity was predom- inately measured spectroscopically, requiring the abundances of metals inferred from both neutral and singly-ionized species to agree (ionization balance). Such measurements tend to suffer from systematic uncertainties that are difficult to fully quantify, re- sulting in independent gravities measured for the same star that differ by much more than the quoted (random) uncertainties. Asteroseismology has pro- vided the key to solving this problem. High preci- sion, long baseline photometric monitoring yield de- tailed oscillation spectra, and the frequency of max- imum oscillation power is directly proportional to surface gravity. TESS is collecting such data over the whole sky, and here we present preliminary mea- surements of asteroseismic log g from a sample of red giant planet hosting stars in the Southern Hemi- sphere. Our sample has been observed by TESS in 2-minute cadence, and we have spectroscopic log g measurements both from heterogeneous sources in the literature and measured homogenously by us. We discuss the frequency with which asteroseismic log g’s differ substantially from the asteroseismic ones (even when spectroscopic measurements agree)
and we explore the implications of revised stellar log g and masses on the interpretation of the planetary companions around these stars.
333.05 — Machine Learning for the Identification of Exomoon Candidates in Kepler
Alex Teachey1; David Kipping1
1 Astronomy, Columbia University (New York, New York, United States)
Convolutional neural networks (CNNs) are well suited for image classification problems, particularly when the data volume is too large for by-eye clas- sification. They have recently been applied with great success to the problem of distinguishing gen- uine planets from false positives in the Kepler, K2, and TESS datasets. In this work we apply a CNN to the Kepler data for the purpose of identifying candidate exomoon signals. We train the CNN on
∼200,000 artificial light curves — real Kepler light curve segments with injected planet/moon signals — to achieve∼95% accuracy for moon signals of suf- ficient SNR in the validation set. We apply the CNN to every transit of every KOI to identify potential exomoons in the data, after which we will vet the most promising candidates with a full photodynam- ical moon fit and Bayesian model selection.
333.06 — Eclipse Mapping: Creating Two- or Three- Dimensional Images of Exoplanets
Emily Rauscher1; Nick B. Cowan2; Megan Mansfield6; Jacob Arcangeli13; Arthur D. Adams11; Ying Feng5;
Prashansa Gupta10; Dylan Keating7; Jacob Lustig-
Yaeger9,12; Everett Schlawin3; Kevin Stevenson4;
Thomas Beatty8
1 Astronomy, University of Michigan (Ann Arbor, Michigan, United States)
2 Département de Physique, Université de Montréal (Montréal, Quebec, Canada)
3 Yale University (New Haven, Connecticut, United States) 4 NExSS Virtual Planetary Laboratory (Seattle, Washington, United States)
5 University of Amsterdam (Amsterdam, Netherlands) 6 McGill University (Montreal, Quebec, Canada)
7 Astronomy, University of Arizona (Tucson, Arizona, United States)
8 STScI (Baltimore, Maryland, United States)
9 Astronomy & Astrophysics, UC Santa Cruz (Santa Cruz, Califor- nia, United States)
10 Geophysical Sciences, University of Chicago (Chicago, Illinois, United States)
11 Physics, McGill University (Montréal, Quebec, Canada) 12 University of Arizona (Tucson, Arizona, United States)
13 University of Washington (Seattle, Washington, United States) Eclipse mapping is a method that can be used to re- solve an image of the day side of an exoplanet. As the planet passes into secondary eclipse, the stellar limb blocks successive slices of the planet disk, while a different set of slices are revealed as the planet comes back out of eclipse. If we measure the de- tailed change in flux during these partially obscured times of ingress and egress, we can reconstruct the brightness distribution across the planet disk. If we take spectra during these times, then different wave- lengths are probing different depths into the atmo- sphere and so these data contain three-dimensional information about the planet’s atmosphere. In prac- tice, eclipse mapping is a nuanced technique, sub- ject to various sources of uncertainty and degener- acy. Here we present a mathematically optimized method for retrieving the maximum possible spatial information from an eclipse mapping dataset. We can also use this method to evaluate whether signifi- cant orbital-mapping degeneracies exist, for any par- ticular system and observational set-up. We then in- troduce a way to extend this framework to include multi-wavelength observations, by using machine learning methods to identify dominant spectral com- ponents and group them into spatial regions. We show applications of this new spectral-spatial map- ping method to test-case toy models, with various ar- tificial atmospheric states, demonstrating its ability to retrieve correct information. Finally, we estimate the scientific return when this method is applied to upcoming JWST data.
333.07 — The Starchive – An Extreme Open Access Archive
Angelle Tanner1; Demitri Muna2
1 Physics and Astronomy, Mississippi State University (Mississippi State, Mississippi, United States)
2 Eureka Scientific (New York, New York, United States)
The Starchive (starchive.org) is an open access, open source stellar database and web application like no other. We have designed an interface which is intu- itive, comprehensive and adaptable. Currently, the database contains multiple stellar samples includ- ing all stars within 30pc, all known brown dwarfs and white dwarfs, stars with planets and circumstel- lar disks and stars in young stellar associations. We have plans to incorporate the WDS, Gaia and TESS catalogs. The web app allows users to search the database using coordinates, names or an ADS ref- erence code. A search can include a single star or
multiple stars (batch mode). If users search for infor- mation on a single star, the result page contains all published measurements and derived physical pa- rameters on that star, a Vizier image as well as any available high contrast images via js9. If the star is in a multiple system, there is a clear hierarchical tree with live links to the other members of the system. If available, users will have access to wavelength cal- ibrated spectra and time series of that star all in one location. If a user submits a list of stars or utilizes the rank list search option, the web app provides a dynamic table of multiple stars with links to each individual star page. Users are able to download a text, .csv or latex file of that table. Directly from the multi-star web page application users will be able to use adaptable plotting tools to visualize the resulting data set. It is the goal of the Starchive that the plots be publication quality thus eliminating the need to download and then replot data for presentations and papers. Registered users will be able to upload data into the database. To ensure the fidelity of the data, we will highly regulate and constantly validate any uploaded data sets. There will be an API available for users to access the database directly from their own code. The front-end scripts will be placed on github and users will be encouraged to contribute new plot- ting tools.
333.08 — Sonifying Solar Systems: New Tools for Research and Outreach
Deborah Kala Perkins1
1 AstroBioethics, AUSN (Woodside, California, United States) Sonifying planetary transits and the possible chem- ical contents of their atmospheres; ALMA’s public Soundbank of molecular data from new star birthing regions; discerning the harmonic resonances be- tween planets in distant solar systems; and Ke- pler Space Telescopes’ “Stellar Choir”, demonstrat- ing with a unique soundscape, playable by the in- quirer, the location of known exoplanetary systems: All of these are now offering sonified data for a unique encounter with exo-planetary science both by the public and research scientists, seeking insights about the universe beyond the visible spectrum. We have found new insights about the solar corona from sonified data which the ear could discern though in- visible to the eye. Sonification is opening an entirely new window for communication with the public, students, and understanding our universe. It is pro- viding those who are visually impaired the ability to explore the universe, experience it, and as well to become astrophysicists. This presentation explores
some of the unique things being done at this fron- tier for outreach, blending culture and science, and research in the realm of Extreme Solar Systems and the quest for other life in the cosmos.
333.09 — Exoplanets in the Antarctic Sky: from Searching to Characterizing
Yu Zhouyi1; Zhang Hui1
1 Nanjing University (Nanjing, China)
Thanks for the wide-field exoplanet surveys on the ground and in the space, thousands of exoplanet samples have been found in the last two decades. From Dome A, the highest point of the Antarctic plateau, we have also contributed over 100 candi- dates using the AST3 telescopes in 2018. Now, be- sides searching, we are progressing forward to study special exoplanet systems in details to reveal their dynamics and physics properties. I will first in- troduce our recent works on searching exoplanets with the help from deep learning methods. And I’ll present some results on characterizing Proxima Cent b, the nearest potential habitable world, using AST3- II. We find a temporary solar-like oscillation in Prox- ima. We know that M dwarf stars are dominated by advection layer, there should be some kinds of Solar- like oscillation. But the oscillation won’t be stable so although believed, no positive detection was made. This may be the first observation proof. This is an excellent example to show the advantages of moni- toring high-value targets from Dome A. To further utilize these advantages I’ll also introduce the KISS (Kunlun Infrared Sky Survey) project and its usage on exoplanet characterization. We also monitored Beta Pictoris a couple of hours each day during the twilights (when the weather was permitting), using AST3 II telescope, in 2017. At the end of the polar winter, we had acquired around 70,000 frames on this target at a cadence of 3.5 sec. Although no ob- vious eclipse was found, we’ve found some new pul- sating frequencies, e.g. around 14.3, 20.6, 58.98/day , and some ultra-high-freqency signals, which are not mentioned before. We think this phenomena can re- veal some properties of Beta Pictoris b’s circumplan- etary environment.
333.10 — The Terrascope: Turning Planets into Telescopes
David Kipping1
1 Columbia University (New York, New York, United States) As our knowledge of exoplanets grows, so to does our thirst for ever more data. Photometric precision
has been gradually improving from percent level with photographic plates, to mmag with ground- based surveys and now in the parts per million with space-based facilities. It is timely to consider where the next order of magnitude gain might come from then, to reach parts per billion precision. In this talk, I’ll discuss the idea of using the Earth as a giant lens of distant starlight exploiting atmospheric refraction — a ”terrascope”. By placing a one-meter aperture at the Earth-Sun L2 point, distant point sources are shown to be amplified by a factor of ∼45,000 with a lensing timescale of∼20 hours, effectively turning a one-meter telescope into a ∼200 meter class tele- scope. I show how the effects of atmospheric extinc- tion and clouds are small provided the terrascope is placed at a large separation from the Earth, such as L2. The terrascope concept is certainly challenged by seeing, turbulence and airglow and I’ll discuss some possible strategies to mitigate these effects.
333.11 — The Mysterious Activity of TRAPPIST-1
Brett Morris1; Eric Agol2; James Davenport2; Suzanne
Hawley2
1 Center for Space and Habitability, University of Bern (Bern, Bern, Switzerland)
2 Astronomy Department, University of Washington (Seattle, Washington, United States)
TRAPPIST-1 is one of the most tantalizing exoplanet systems discovered to date, with seven Earth-sized transiting exoplanets in a resonant chain orbiting an ultra-cool dwarf star. To make robust infer- ences about the properties of the exoplanets orbiting TRAPPIST-1, we must first identify any stellar sur- face inhomogeneities which will confound exoplanet transmission spectroscopy (Morris et al. 2018, Rack- ham et al. 2018, Ducrot et al. 2018). TRAPPIST-1 is the first M8V star to be scrutinized with long-term
∼1% precision photometry in multiple wavebands, and preliminary analyses of the surface features of the host star are full of surprises. There is no defini- tive evidence for coverage of the stellar surface by dark starspots, but there is photometric and spectro- scopic evidence for bright, hot regions on the sur- face of the star. Furthermore, the occurence of flares seems to be correlated with the optical flux of the star, perhaps suggesting that the apparent rotational modulation of the star could instead be evolution of bright active regions. We will discuss the available evidence for activity and rotation of the host star, and conclude with a discussion of the implications for transmission spectroscopy of the exoplanets.
333.12 — The Transiting Exoplanet Survey Satellite (TESS): Mission Operations and Instrument Per- formance
Roland Vanderspek1
1 MIT Kavli Institute for Astrophysics and Space Science, Mas- sachusetts Institute of Technology (Cambridge, Massachusetts, United States)
The Transiting Exoplanet Survey Satellite (TESS) is performing a near-all-sky survey to detect exoplan-