N. Peixinho

University of Coimbra

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A. Delsanti

Laboratoire d’Astrophysique de Marseille

A. Doressoundiram

Université Paris Cité

J. Skottfelt

The Open University

C. Snodgrass

Royal Observatory

S. Rahvar

Sharif University of Technology

M. Dominik

University of St Andrews

U. G. Jørgensen

University of Copenhagen

M. Hundertmark

Heidelberg University

Michele T. Bannister

University of Canterbury

V. Bozza

University of Salerno

Cooperative Institutions

Centre National de la Recherche Scientifique

146

Instituto de Astrofísica de Canarias

115

Sorbonne Université

Max Planck Society

Observatoire de Paris

Laboratoire d’études spatiales et d’instrumentation en astrophysique

Max Planck Institute for Astronomy

Université Paris Cité

Universidad de La Laguna

Korea Astronomy and Space Science Institute

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Centaur-Sized KBOs Also Show Bimodal Colors

European Planetary Science Congress 2012 (2012)

N. Peixinho A. Delsanti Aurélie Guilbert-Lepoutre R. Gafeira Pedro Lacerda

Centaur

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VizieR Online Data Catalog: WASP-22, WASP-41, WASP-42, WASP-55 (Southworth+, 2016)

Monthly Notices of the Royal Astronomical Society (2018)

J. Southworth J. Tregloan-Reed M. I. Andersen S. Calchi Novati S. Ciceri

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THE FIRST SIMULTANEOUS MICROLENSING OBSERVATIONS BY TWO SPACE TELESCOPES: SPITZER AND SWIFT REVEAL A BROWN DWARF IN EVENT OGLE-2015-BLG-1319

The Astrophysical Journal (2016)

Yossi Shvartzvald Zhexing Li A. Udalski Andrew Gould T. Sumi

Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax". We report the discovery of a 30-55$M_J$ brown dwarf orbiting a K dwarf in microlensing event OGLE-2015-BLG-1319. The system is located at a distance of $\sim$5 kpc toward the Galactic bulge. The event was observed by several ground-based groups as well as by $Spitzer$ and $Swift$, allowing the measurement of the physical properties. However, the event is still subject to an 8-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either $\sim$0.25 AU or $\sim$45 AU. This is the first microlensing event observed by $Swift$, with the UVOT camera. We study the region of microlensing parameter space to which $Swift$ is sensitive, finding that while for this event $Swift$ could not measure the microlens parallax with respect to ground-based observations, it can be important for other events. Specifically, for detecting nearby brown dwarfs and free-floating planets in high magnification events.

Gravitational microlensing

Swift

Parallax

Spitzer Space Telescope

Microlens

10.3847/0004-637x/831/2/183

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TNOs AND CENTAURS: THERMAL MODELS, SPECTROSCOPY, AND SURVEYS 4:00 p.m. Harborside D

M. A. Barucci Michael Mueller Kuiper Belt Spencer J. Stansberry J. Grundy

Centaur

Trans-Neptunian object

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The bimodal colors of Centaurs and small Kuiper belt objects

Astronomy and Astrophysics (2012)

N. Peixinho A. Delsanti A. Guilbert-Lepoutre R. Gafeira Pedro Lacerda

Ever since the very first photometric studies of Centaurs and Kuiper belt objects (KBOs) their visible color distribution has been controversial. This controversy has triggered to a prolific debate on the origin of the surface colors of these distant icy objects of the solar system. Two scenarios have been proposed to interpret and explain the large variability of colors, hence surface composition. Are the colors mainly primordial and directly related to the formation region, or are they the result of surface evolution processes? To date, no mechanism has been found that successfully explains why Centaurs, which are escapees from the Kuiper belt, exhibit two distinct color groups, whereas KBOs do not. We readdress this issue using a carefully compiled set of B − R colors and HR(α) magnitudes (as proxy for size) for 253 objects, including data for 10 new small objects. We find that the bimodal color distribution of Centaurs is a size-related phenomenon, common to both Centaurs and small KBOs, i.e. independent of dynamical classification. Furthermore, we find that large KBOs also have a bimodal distribution of surface colors, albeit distinct from the small objects and strongly dependent on the "Haumea collisional family" objects. When plotted in B − R, HR(α) space, the colors of Centaurs and KBOs display a peculiar 𝒩 shape.

Centaur

10.1051/0004-6361/201219057

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Citations (53)

From Centaurs to comets: 40 Years

Elsevier eBooks (2019)

N. Peixinho Audrey Thirouin S. C. Tegler R. P. Di Sisto A. Delsanti

Centaur

Trans-Neptunian object

10.1016/b978-0-12-816490-7.00014-x

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Analysis of classical Kuiper-belt objects and Haumea collisional family from the Herschel and Spitzer observations

E. Vilenius J. A. Stansberry T. Müller Csaba Kiss M. Mommert

We have analyzed space-based data at far-IR wavelengths in order to determine physical properties of Kuiper-belt objects (KBOs), also known as transneptunian objects (TNO), in the dynamical class of classical Kuiper-belt objects (CKBO). This dynamical class also contains most of the Haumea family members, the only known collisional family among TNOs. We observed 44 CKBOs in the Herschel open time key program ''TNOs are are Cool'' (Muller et al. 2009). We use Herschel/PACS/photometer data (70, 100, 160 μ m) combined with earlier Spitzer/MIPS (24 and 70 μ m) data when available. Additionally, half a dozen CKBOs have data only from Spitzer. We have re-examined absolute visual magnitudes based on various optical data in the literature. We determine sizes, geometric albedos and beaming factors using the radiometric technique. The CKBOs with radiometrically measured diameters are in the size range 130

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A search for transit timing variations in the HATS-18 planetary system

arXiv (Cornell University) (2022)

J. Southworth Adrian J. Barker T. C. Hinse Y. Jongen M. Dominik

HATS-18b is a transiting planet with a large mass and a short orbital period, and is one of the best candidates for the detection of orbital decay induced by tidal effects. We present extensive photometry of HATS-18 from which we measure 27 times of mid-transit. Two further transit times were measured from data from the Transiting Exoplanet Survey Satellite (TESS) and three more taken from the literature. The transit timings were fitted with linear and quadratic ephemerides and an upper limit on orbital decay was determined. This corresponds to a lower limit on the modified stellar tidal quality factor of $Q_\star^{\,\prime} > 10^{5.11 \pm 0.04}$. This is at the cusp of constraining the presence of enhanced tidal dissipation due to internal gravity waves. We also refine the measured physical properties of the HATS-18 system, place upper limits on the masses of third bodies, and compare the relative performance of TESS and the 1.54-m Danish Telescope in measuring transit times for this system.

Orbital decay

Ephemeris

Orbital period

Hot Jupiter

10.48550/arxiv.2207.05873

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Visible and Near Infrared colors of Trans-neptunian Objects

HAL (Le Centre pour la Communication Scientifique Directe) (2007)

A. Doressoundiram N. Peixinho

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