Dynamical Mass Measurement of the Young Spectroscopic Binary V343 Normae AaAb Resolved With the Gemini Planet Imager

We present new spatially resolved astrometry and photometry from the Gemini Planet Imager of the inner binary of the young multiple star system V343 Normae, which is a member of the beta Pictoris moving group. V343 Normae comprises a K0 and mid-M star in a ~4.5 year orbit (AaAb) and a wide 10" M5 companion (B). By combining these data with archival astrometry and radial velocities we fit the orbit and measure individual masses for both components of M_Aa = 1.10 +/- 0.10 M_sun and M_Ab = 0.290 +/- 0.018 M_sun. Comparing to theoretical isochrones, we find good agreement for the measured masses and JHK band magnitudes of the two components consistent with the age of the beta Pic moving group. We derive a model-dependent age for the beta Pic moving group of 26 +/- 3 Myr by combining our results for V343 Normae with literature measurements for GJ 3305, which is another group member with resolved binary components and dynamical masses.Comment: 12 pages, 7 figures. Accepted to A

GPI spectra of HR 8799 c, d, and e from 1.5 to 2.4μ\mum with KLIP Forward Modeling

We explore KLIP forward modeling spectral extraction on Gemini Planet Imager coronagraphic data of HR 8799, using PyKLIP and show algorithm stability with varying KLIP parameters. We report new and re-reduced spectrophotometry of HR 8799 c, d, and e in H & K bands. We discuss a strategy for choosing optimal KLIP PSF subtraction parameters by injecting simulated sources and recovering them over a range of parameters. The K1/K2 spectra for HR 8799 c and d are similar to previously published results from the same dataset. We also present a K band spectrum of HR 8799 e for the first time and show that our H-band spectra agree well with previously published spectra from the VLT/SPHERE instrument. We show that HR 8799 c and d show significant differences in their H & K spectra, but do not find any conclusive differences between d and e or c and e, likely due to large error bars in the recovered spectrum of e. Compared to M, L, and T-type field brown dwarfs, all three planets are most consistent with mid and late L spectral types. All objects are consistent with low gravity but a lack of standard spectra for low gravity limit the ability to fit the best spectral type. We discuss how dedicated modeling efforts can better fit HR 8799 planets' near-IR flux and discuss how differences between the properties of these planets can be further explored.Comment: Accepted to AJ, 25 pages, 16 Figure

The Lantern, 2016-2017

• Our Lady of Perpetual Virginity • Essential Terms for the Audience • Stories Untold • Jesus Camp • The Second Avenue Schmear • Driving to the Beach • Thanks, Alice • Decay • Peanut Butter Rhapsody • Transactions • Traffic • Sissy • Melting Wings • Ocean • Small Town Summer • Third Story • Family Trees • Mixed, Just Like Me • Sour Graves • How Sweet the Sound • Goodnight, Halfmoon • I\u27m Going to Ask Him How • Music • Pizza • Manhoodlike • Meditations From a Bunk Bed in a Home on Mount Pocono • Soft • Twilight\u27s Palette • The Oracle • Cynicism • River Ganges • Pinata Body and Hearing the Gun Shot • Song With No Music • Of Mornings Considering Womanhood • 10 Hours in Philadelphia • To Cut • Sachrang • Bavarian Wave Swinger • Irish Rain • Remembrances, Well • The Roses • Buttermilk • The Universe Will Always Listen if You Ask Her, Which is Why I Like Her More Than God • A Lukewarm Light • A Thought of Death • Hobson • Decaying Light • Window Women • Dead Bee • The Imagery • For Rent • Mona Lisa MMXVIhttps://digitalcommons.ursinus.edu/lantern/1185/thumbnail.jp

The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics from 10 To 100 Au

We present a statistical analysis of the first 300 stars observed by the Gemini Planet Imager Exoplanet Survey. This subsample includes six detected planets and three brown dwarfs; from these detections and our contrast curves we infer the underlying distributions of substellar companions with respect to their mass, semimajor axis, and host stellar mass. We uncover a strong correlation between planet occurrence rate and host star mass, with stars M ∗ \u3e1.5 M o more likely to host planets with masses between 2 and 13M Jup and semimajor axes of 3-100 au at 99.92% confidence. We fit a double power-law model in planet mass (m) and semimajor axis (a) for planet populations around high-mass stars (M ∗ \u3e1.5 M o) of the form , finding α = -2.4 +0.8 and β = -2.0 +0.5, and an integrated occurrence rate of % between 5-13M Jup and 10-100 au. A significantly lower occurrence rate is obtained for brown dwarfs around all stars, with % of stars hosting a brown dwarf companion between 13-80M Jup and 10-100 au. Brown dwarfs also appear to be distributed differently in mass and semimajor axis compared to giant planets; whereas giant planets follow a bottom-heavy mass distribution and favor smaller semimajor axes, brown dwarfs exhibit just the opposite behaviors. Comparing to studies of short-period giant planets from the radial velocity method, our results are consistent with a peak in occurrence of giant planets between ∼1 and 10 au. We discuss how these trends, including the preference of giant planets for high-mass host stars, point to formation of giant planets by core/pebble accretion, and formation of brown dwarfs by gravitational instability

First Resolved Scattered-Light Images of Four Debris Disks in Scorpius-Centaurus with the Gemini Planet Imager

We present the first spatially resolved scattered-light images of four debris disks around members of the Scorpius-Centaurus (Sco-Cen) OB association with high-contrast imaging and polarimetry using the Gemini Planet Imager (GPI). All four disks are resolved for the first time in polarized light, and one disk is also detected in total intensity. The three disks imaged around HD 111161, HD 143675, and HD 145560 are symmetric in both morphology and brightness distribution. The three systems span a range of inclinations and radial extents. The disk imaged around HD 98363 shows indications of asymmetries in morphology and brightness distribution, with some structural similarities to the HD 106906 planet-disk system. Uniquely, HD 98363 has a wide comoving stellar companion, Wray 15-788, with a recently resolved disk with very different morphological properties. HD 98363 A/B is the first binary debris disk system with two spatially resolved disks. All four targets have been observed with ALMA, and their continuum fluxes range from one nondetection to one of the brightest disks in the region. With the new results, a total of 15 A/F stars in Sco-Cen have resolved scattered-light debris disks, and approximately half of these systems exhibit some form of asymmetry. Combining the GPI disk structure results with information from the literature on millimeter fluxes and imaged planets reveals a diversity of disk properties in this young population. Overall, the four newly resolved disks contribute to the census of disk structures measured around A/F stars at this important stage in the development of planetary systems

An Updated Visual Orbit of the Directly Imaged Exoplanet 51 Eridani b and Prospects for a Dynamical Mass Measurement with \u3ci\u3eGaia\u3c/i\u3e

We present a revision to the visual orbit of the young, directly imaged exoplanet 51 Eridani b using four years of observations with the Gemini Planet Imager. The relative astrometry is consistent with an eccentric (e= 0.53-0.13+0.09) orbit at an intermediate inclination (i= 13611+10°), although circular orbits cannot be excluded due to the complex shape of the multidimensional posterior distribution. We find a semimajor axis of 11.1-1.3+4.2 au and a period of 28.1-4.9+17.2 yr, assuming a mass of 1.75 M· for the host star. We find consistent values with a recent analysis of VLT/SPHERE data covering a similar baseline. We investigate the potential of using the absolute astrometry of the host star to obtain a dynamical mass constraint for the planet. The astrometric acceleration of 51 Eri derived from a comparison of the Hipparcos and Gaia catalogs was found to be inconsistent at the 2ω-3ω level with the predicted reflex motion induced by the orbiting planet. Potential sources of this inconsistency include a combination of random and systematic errors between the two astrometric catalogs and the signature of an additional companion within the system interior to current detection limits. We also explored the potential of using Gaia astrometry alone for a dynamical mass measurement of the planet by simulating Gaia measurements of the motion of the photocenter of the system over the course of the extended 8 yr mission. We find that such a measurement is only possible (\u3e98% probability) given the most optimistic predictions for the Gaia scan astrometric uncertainties for bright stars and a high mass for the planet (≳3.6 MJup)

Imaging the 44 au Kuiper Belt Analog Debris Ring around HD 141569A With GPI Polarimetry

We present the first polarimetric detection of the inner disk component around the pre-main-sequence B9.5 star HD 141569A. Gemini Planet Imager H-band (1.65 μm) polarimetric differential imaging reveals the highest signal-to-noise ratio detection of this ring yet attained and traces structure inward to 0.″25 (28 au at a distance of 111 pc). The radial polarized intensity image shows the east side of the disk, peaking in intensity at 0.″40 (44 au) and extending out to 0.″9 (100 au). There is a spiral arm-like enhancement to the south, reminiscent of the known spiral structures on the outer rings of the disk. The location of the spiral arm is coincident with 12CO J = 3-2 emission detected by ALMA and hints at a dynamically active inner circumstellar region. Our observations also show a portion of the middle dusty ring at ∼220 au known from previous observations of this system. We fit the polarized H-band emission with a continuum radiative transfer Mie model. Our best-fit model favors an optically thin disk with a minimum dust grain size close to the blowout size for this system, evidence of ongoing dust production in the inner reaches of the disk. The thermal emission from this model accounts for virtually all of the far-infrared and millimeter flux from the entire HD 141569A disk, in agreement with the lack of ALMA continuum and CO emission beyond ∼100 au. A remaining 8-30 μm thermal excess a factor of ∼2 above our model argues for an as-yet-unresolved warm innermost 5-15 au component of the disk

The Lantern, 2017-2018

On Dissociation • Untouchable • After Rocket Man • The Science Fair • Cardinal Rule at Stephen J. Memorial • Quentin & Sylvie • Cabello • The Get Out • Painting Day • Black, White and Grey • Family Pruning • How to Remove a Stain • Becoming Ourselves • Wonderbread U • Overture • Pescadero • Gross • Stage Fright • Lucky Daddy • Sarah • Rumble • Silvermine • The Green Iguana • A Poem for Ghost Children • A Poem for Lost Boys • Mother • Drop of Grease • Don\u27t Wanna be White • I • Amelia Earhart Disappeared Into My Vagina: An Ode to Cunts, Menstrual Cups and All Things Woman • Suburban Summer • Nightmares and Dreams Induced by My Mother • Teacups, Skins, etc. • Three Thoughts About My Bedroom • Dear Siri • 2 Queens (Beyonce in Reference to Sonia Sanchez) • Voyeurs • In Front of the Bathroom Mirror • To a Rose • Howl • Mice • Mirror • Language Accordion Volcano Mouth • Lucky Woman • Butterscotch • To Persephone • Wolf • Notes Never Passed • Topple • Bust • Kyoto • Identity • Sunflower • Tornabuoni Bubbles • Olympia • Decayed Hall • Perspectivehttps://digitalcommons.ursinus.edu/lantern/1186/thumbnail.jp

The Lantern, 2015-2016

• Ghosts • Going to China • 98% Guaranteed • Constellation/Boulevard • Prayer • The Little One • Burning • The Amber Macaroon • Becoming • Requiem • Construction Site • Thirteen Ways of Looking at a Dragon • Charlie • No Sleep • A Lesson in Physical Education • Statues • Who Can Love a Black Woman? • Apples • Fun Craft • The Door at Midnight • Eve as a Book in the Bible • Boys • Diamond Heart • To Apollo • Joanne and Her July Garden • Option A, 1936 • Young White Girls, Hollow Bodies, and Home • Mama\u27s Stance on Sugar • The Mariana Trench • Hurricane • Part of the Job • Avenue H Blues • Hour of Nones • Send Toilet Paper • Grave Robbing • Wild Turkey • The Creek • Let\u27s Go for a Walk • Deaconess • Border of Love • Your Father, Rumpelstiltskin • Purchasing Poplars • Red Tatters • Sunken • Whispers • Existence • God Took a Cigarette Break with Police Officers • Martian Standoff • In the Headlights • It\u27s a Subtle Thing • Dear Kent • Hanako-san • A Brief Interlude • On Fencing, Gummy Worms, and my Inescapable Fear of Living in the Moment • Stolen Soul • Block • Mortem Mei Fratris • Kalki • Lake Placid • Atom and Eve • The Baerie Queene • Gladston • Soldiers at Gettysburg • Pattern • Foliage • Mass Media • Arrow • Move Out • Wanderers • Riverside Gardenhttps://digitalcommons.ursinus.edu/lantern/1182/thumbnail.jp

An Optical/Near-infrared Investigation of HD 100546 b with the Gemini Planet Imager and MagAO

We present H band spectroscopic and Hα photometric observations of HD 100546 obtained with the Gemini Planet Imager and the Magellan Visible AO camera. We detect H band emission at the location of the protoplanet HD 100546 b, but show that the choice of data processing parameters strongly affects the morphology of this source. It appears point-like in some aggressive reductions, but rejoins an extended disk structure in the majority of the others. Furthermore, we demonstrate that this emission appears stationary on a timescale of 4.6 years, inconsistent at the 2σ level with a Keplerian clockwise orbit at 59 au in the disk plane. The H band spectrum of the emission is inconsistent with any type of low effective temperature object or accreting protoplanetary disk. It strongly suggests a scattered-light origin, as this is consistent with the spectrum of the star and the spectra extracted at other locations in the disk. A non-detection at the 5σ level of HD 100546 b in differential Hα imaging places an upper limit, assuming the protoplanet lies in a gap free of extinction, on the accretion luminosity of 1.7 × 10−4 L ⊙ and $M\dot{M}\lt 6.3\times {10}^{-7}\,{M}_{\mathrm{Jup}}^{2}\,{\mathrm{yr}}^{-1}$ for 1 R Jup. These limits are comparable to the accretion luminosity and accretion rate of T-Tauri stars or LkCa 15 b. Taken together, these lines of evidence suggest that the H band source at the location of HD 100546 b is not emitted by a planetary photosphere or an accreting circumplanetary disk but is a disk feature enhanced by the point-spread function subtraction process. This non-detection is consistent with the non-detection in the K band reported in an earlier study but does not exclude the possibility that HD 100546 b is deeply embedded