Article
Astronomy & Astrophysics
R. Arun, Blesson Mathew, G. Maheswar, Tapas Baug, Sreeja S. Kartha, G. Selvakumar, P. Manoj, B. Shridharan, R. Anusha, Mayank Narang
Summary: The study focuses on the formation and kinematic evolution of the early-type Herbig Be star IL Cep and its environment. It is found that the B0V star HD 216658, which is associated with IL Cep, is capable of creating the cavity. Analysis of Gaia EDR3 astrometry reveals 79 co-moving stars around IL Cep, grouped into two populations associated with IL Cep and HD 216658, respectively.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
L. Hambalek, V Krushevska, T. Pribulla, M. Vanko, J. Budaj, M. Fiorucci, Z. Garai, E. Guenther, R. Komzik, E. Kundra, U. Munari, B. Smalley
Summary: This study presents the results of long-term spectroscopic monitoring of 21 T-Tauri stars in the Taurus-Auriga star-forming region. The analysis reveals no close binary companion and provides information about atmospheric parameters, age, mass, and radius of the stars. The findings indicate that these stars are young with ages younger than 50 Myr, average age of 5±3 Myr, mass between 0.75 and 2.10 M-circle dot, and minimum radii in the range 0.60-3.17 R-circle dot.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Zhen Guo, P. W. Lucas, L. C. Smith, C. Clarke, C. Contreras Pena, A. Bayo, C. Briceno, J. Elias, R. G. Kurtev, J. Borissova, J. Alonso-Garcia, D. Minniti, M. Catelan, F. Nikzat, C. Morris, N. Miller
Summary: This article presents the results of near-infrared photometry obtained by the VVV survey over the past decade, focusing on the Galactic bulge and the southern disc plane. A modified Lomb-Scargie method was used to search for large-amplitude mid to long-term periodic variables, leading to the discovery of 1520 periodic sources, including 59 candidate periodic outbursting young stellar objects. The study also found different types of periodic outbursts and suggested that these cycles may be caused by dynamical perturbations from stellar or planetary companions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. Sicilia-Aguilar, J. Campbell-White, V Roccatagliata, J. Desira, S. G. Gregory, A. Scholz, M. Fang, F. Cruz-Saenz de Miera, A. Kospal, S. Matsumura, P. Abraham
Summary: This study examines the long-term spectroscopic and photometric variability of two young stars, EX Lupi and TW Hya, to explore the presence of stable accretion and its role in observed changes. The research reveals that the accretion columns of both stars are remarkably stable, while the continuum emission is highly variable. The analysis also uncovers further structures in the emission lines and suggests that stable accretion footprints could be used to identify young planets.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
C. Koen
Summary: The study aims to investigate the photometric variability in the candidate host star CVSO 30 and determine if it can be explained by starspots. By separating the TESS light curve into two independent non-sinusoidal periodic components and applying starspot modelling technique, the two model light curves combined accurately reproduce the TESS observations, eliminating the need for invoking planetary transits to describe the variability.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. Koen
Summary: The photometry of 10 young stars from the 'Transiting Exoplanet Survey Satellite' with complex periodic light curves was considered. It was found that almost all light curves can be accurately modeled by re-evaluating the ratios of spot to photospheric fluxes, although the caveat that these models are not unique applies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Zsofia Nagy, Sunkyung Park, Peter Abraham, Agnes Kospal, Fernando Cruz-Saenz de Miera, Maria Kun, Michal Siwak, Zsofia Marianna Szabo, Mate Szilagyi, Eleonora Fiorellino, Teresa Giannini, Jae-Joon Lee, Jeong-Eun Lee, Gabor Marton, Laszlo Szabados, Fabrizio Vitali, Jan Andrzejewski, Mariusz Gromadzki, Simon Hodgkin, Maja Jablonska, Rene A. Mendez, Jaroslav Merc, Olga Michniewicz, Przemyslaw J. Mikolajczyk, Uliana Pylypenko, Milena Ratajczak, Lukasz Wyrzykowski, Michal Zejmo, Pawel Zielinski
Summary: In this study, the researchers analyzed the spectroscopy of Gaia21elv, a young stellar object, and confirmed it as a classical FUor, the third such object discovered among the Gaia science alerts. The spectroscopy showed typical FUor signatures, such as a triangular shaped H-band continuum, absorption-line dominated spectrum, and P Cygni profiles. Additionally, [O I], [FeII], and [S II] were detected, suggesting the presence of a jet or disc wind.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Zsofia Nagy, Elza Szegedi-Elek, Peter Abraham, Agnes Kospal, Attila Bodi, Jerome Bouvier, Maria Kun, Attila Moor, Borbala Cseh, Aniko Farkas-Takacs, Otto Hanyecz, Simon Hodgkin, Bernadett Ignacz, Csaba Kiss, Reka Konyves-Toth, Levente Kriskovics, Gabor Marton, Laszlo Meszaros, Andras Ordasi, Andras Pal, Paula Sarkis, Krisztian Sarneczky, Adam Sodor, Laszlo Szabados, Zsofia Marianna Szabo, Robert Szakats, Dora Tarczay-Nehez, Krisztian Vida, Gabriella Zsidi
Summary: The study found that V555 Ori, a T Tauri star, experienced brightness variations mainly due to extinction effects, showing long-term and short-term brightness oscillations. Its low accretion rate is not enough to explain the optical flux changes, similar to AA Tau. The periodic behavior of V555 Ori was detectable in both high and low brightness states.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Zsofia Nagy, Peter Abraham, Agnes Kospal, Sunkyung Park, Michal Siwak, Fernando Cruz-Saenz de Miera, Eleonora Fiorellino, David Garcia-Alvarez, Zsofia Marianna Szabo, Simone Antoniucci, Teresa Giannini, Alessio Giunta, Levente Kriskovics, Maria Kun, Gabor Marton, Attila Moor, Brunella Nisini, Andras Pal, Laszlo Szabados, Pawel Zielinski, Lukasz Wyrzykowski
Summary: This study investigates two young stars that experienced brightness increases on a year-long time scale. The analysis of light curves, photometry, and spectra reveals that these stars have similar accretion parameters to classical T Tauri stars, but their brightness amplitudes and time scales place them in a region of the parameter space rarely occupied by young stars. This suggests the existence of a new class of young stars that produce outbursts similar to young eruptive stars, but with smaller amplitudes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. Filocomo, J. F. Albacete-Colombo, E. Mestre, L. J. Pellizza, J. A. Combi
Summary: In this study, we propose that NGC 2071 star-forming region could be a counterpart to some unidentified gamma-ray sources. By analyzing the data from the Fermi satellite, we have found that the gamma-ray source in NGC 2071 was detectable during the first 2 years of observation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. Melnikov, P. A. Boley, N. S. Nikonova, A. Caratti O. Garatti, R. Garcia Lopez, B. Stecklum, J. Eisloeffel, G. Weigelt
Summary: The study examines the Th 28 jet and finds that the brightness of its jet lobes is asymmetric, possibly due to asymmetry in the physical parameters of the jet plasma in opposite jet lobes. High-resolution observations using the SINFONI instrument reveal differences in the jet parameters and structures, and comparisons with other asymmetric YSO jets help determine the physical origin of these asymmetries.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Asen Mutafov, Evgeni Semkov, Stoyanka Peneva, Sunay Ibryamov
Summary: This paper reports the results of optical photometric observations of the pre-main sequence star V1180 Cas. The star shows large amplitude variability, which is interpreted as a combination of accretion-induced and extinction-driven effects. By comparing the photometric data with observations of other low-mass pre-main sequence objects, a better understanding of the properties of these celestial bodies can be obtained.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Elizaveta Ryspaeva, Alexander Kholtygin, Maxim Lyutikov
Summary: We reanalyse archival X-ray data of 16 Ae/Be Herbig stars obtained by the XMM-Newton and Chandra satellites. We find that the unabsorbed X-ray luminosity of Herbig stars is dependent on stellar mass and radius, similar to that for T Tauri stars. The accretion rates, rotation periods, and surface magnetic fields of Herbig stars follow a tight correlation predicted by the standard magnetospheric accretion theory. We suggest that X-ray emission from Herbig stars is powered by magnetic reconnection events in the tenuous corona at the disc-magnetosphere boundary.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
K. Lange, C. Dominik, A. G. G. M. Tielens
Summary: This study investigates the reduction of polycyclic aromatic hydrocarbons (PAHs) in protoplanetary discs through clustering and adsorption on dust grains. The research finds that once PAHs are frozen on the dust grain surface, the high heat capacity of these clusters prevents them from evaporating off in UV-rich environments, leading to the depletion of gas-phase PAHs in the discs.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
K. Lange, C. Dominik, A. G. G. M. Tielens
Summary: The study investigates the formation and survival of PAH clusters in protoplanetary discs around Herbig Ae/Be and T Tauri stars, showing that PAH dimers can form in the inner 100 AU of these discs and may grow beyond dimer size in a short time. While PAH clusters may not survive in the photosphere of Herbig stars due to high UV radiation, they are possible in T Tauri discs, suggesting cluster formation as a potential explanation for low PAH detection rates in these systems.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Zhoujian Zhang, Brendan P. Bowler, Trent J. Dupuy, Timothy D. Brandt, G. Mirek Brandt, William D. Cochran, Michael Endl, Phillip J. MacQueen, Kaitlin M. Kratter, Howard T. Isaacson, Kyle Franson, Adam L. Kraus, Caroline V. Morley, Yifan Zhou
Summary: We present a precise characterization of the ancient Kepler-444 system, consisting of a primary star hosting five planets and a tight binary. Our measurements using adaptive optics imaging and radial velocities suggest a more accurate orbital analysis and new dynamical masses for the binary components. The system's dynamics indicate that compact multiplanet systems in hierarchical stellar triples can form and survive early epochs of the universe.
ASTRONOMICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Vighnesh Nagpal, Sarah Blunt, Brendan P. Bowler, Trent J. Dupuy, Eric L. Nielsen, Jason J. Wang
Summary: We study the impact of hyperpriors on the population-level eccentricity distributions of directly imaged substellar companions and find that the choice of hyperprior significantly affects the inferred eccentricity distribution. We reanalyze the observational sample of imaged giant planets and find that the eccentricity distribution is consistent with that of close-in exoplanets detected using radial velocities. Our analysis supports the conclusion that long-period giant planets and brown dwarfs have different eccentricity distributions and this conclusion is robust to the choice of hyperprior.
ASTRONOMICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Mairi W. O'Brien, P-E Tremblay, N. P. Gentile Fusillo, M. A. Hollands, B. T. Gansicke, D. Koester, I Pelisoli, E. Cukanovaite, T. Cunningham, A. E. Doyle, A. Elms, J. Farihi, J. J. Hermes, J. Holberg, S. Jordan, B. L. Klein, S. J. Kleinman, C. J. Manser, D. De Martino, T. R. Marsh, J. McCleery, C. Melis, A. Nitta, S. G. Parsons, R. Raddi, A. Rebassa-Mansergas, M. R. Schreiber, R. Silvotti, D. Steeghs, O. Toloza, S. Toonen, S. Torres, A. J. Weinberger, B. Zuckerman
Summary: We conducted a spectroscopic survey of 248 white dwarf candidates within a distance of 40 pc from the Sun, with 244 of them located in the Southern hemisphere. Using the Very Large Telescope and Southern Astrophysical Research Telescope, we confirmed a total of 246 white dwarfs, with 209 having no previously published spectra. Among the identified white dwarfs, 100 display hydrogen Balmer lines, 69 have featureless spectra, and two show only neutral helium lines. Additionally, we observed 35 magnetic white dwarfs through Zeeman splitting of their spectral lines.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Trent J. Dupuy, Michael C. Liu, Elise L. Evans, William M. J. Best, Logan A. Pearce, Aniket Sanghi, Mark W. Phillips, Daniella C. Bardalez Gagliuffi
Summary: VHS J1256-1257 AB is an ultracool dwarf binary with a wide-separation planetary-mass companion. The binary's orbit (a = 1.96 +/- 0.03 au, P = 7.31 +/- 0.02 yr, e = 0.883 +/- 0.003) and total mass (0.141 +/- 0.008 M-circle dot) have been determined. The wide companion's orbit is eccentric (e=0.68(-0.10)(+0.11)) and has a mutual inclination of 115 degrees +/- 14 degrees with respect to the central binary. The cooling age of VHS J1256-1257 AB is estimated to be 140 +/- 20 Myr. The mass of VHS J1256-1257 b is found to have a bimodal probability distribution, either 12.0 +/- 0.1 M-Jup or 16 +/- 1 M-Jup.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Joseph D. Long, Jared R. Males, Sebastiaan Y. Haffert, Logan Pearce, Mark S. Marley, Katie M. Morzinski, Laird M. Close, Gilles P. P. L. Otten, Frans Snik, Matthew A. Kenworthy, Christoph U. Keller, Philip Hinz, John D. Monnier, Alycia Weinberger, Volker Tolls
Summary: Using Magellan Adaptive Optics (MagAO) system and Clio camera in infrared light, we set strict mass constraints on potential undetected companions to Sirius A. Employing the grating vector-apodizing phase plate coronagraph and the eigen time series approach, we achieve improved contrast and computational efficiency in postprocessing the data. By combining these results with previous studies, we can conclude that 99% of >= 9 M (J) planets are ruled out within the range of 2.5 to 7 au.
ASTRONOMICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Kendall Sullivan, Adam L. Kraus, Daniel Huber, Erik A. Petigura, Elise Evans, Trent Dupuy, Jingwen Zhang, Travis A. Berger, Eric Gaidos, Andrew W. Mann
Summary: Binary stars are common, especially among solar-type stars. While the presence of planets is less likely in binary systems, there are still some multiple star systems that host planets. These binary systems introduce observational biases and make transiting planets appear smaller. In this study, we analyzed 119 binary star systems with planets from the Kepler mission and found no significant evidence of a radius gap in our sample, suggesting that the planet size distribution differs between binary and single star systems.
ASTRONOMICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Shubh Agrawal, Jean-Baptiste Ruffio, Quinn M. Konopacky, Bruce Macintosh, Dimitri Mawet, Eric L. Nielsen, Kielan K. W. Hoch, Michael C. Liu, Travis S. Barman, William Thompson, Alexandra Z. Greenbaum, Christian Marois, Jenny Patience
Summary: We demonstrate that moderate-resolution integral-field spectrographs can detect planets at smaller separations by detecting their distinct spectral signature compared to the host star. Using OSIRIS at the W.M. Keck Observatory, we present the results of a planet search around young targets in star-forming regions. Our technique outperforms high-contrast coronagraphic instruments in the small separation regime.
ASTRONOMICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
John Debes, Rebecca Nealon, Richard Alexander, Alycia J. Weinberger, Schuyler Grace Wolff, Dean Hines, Joel Kastner, Hannah Jang-Condell, Christophe Pinte, Peter Plavchan, Laurent Pueyo
Summary: We present new visible-light imaging of the TW Hya disk using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope. The images show two separate shadows, indicating a change in behavior of the occulting structure. Based on radiative-transfer models, we suggest that the change is due to two misaligned components of the inner disk. More observations are needed to understand the nature of TW Hya's inner-disk architecture.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Alexandra E. Doyle, Beth L. Klein, Patrick Dufour, Carl Melis, B. Zuckerman, Siyi Xu, Alycia J. Weinberger, Isabella L. Trierweiler, Nathaniel N. Monson, Michael A. Jura, Edward D. Young
Summary: We present observations and analyses of eight white dwarf stars that have accreted rocky material from planetary systems. The spectra of these stars contain detectable optical lines of major rock-forming elements. The composition of the accreted material is similar to that of chondritic meteorites. These results support the conclusion that extrasolar rocky bodies resemble those in our solar system.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Feng Long, Bin B. Ren, Nicole L. Wallack, Daniel Harsono, Gregory J. Herczeg, Paola Pinilla, Dimitri Mawet, Michael C. Liu, Sean M. Andrews, Xue-Ning Bai, Sylvie Cabrit, Lucas A. Cieza, Doug Johnstone, Jarron M. Leisenring, Giuseppe Lodato, Yao Liu, Carlo F. Manara, Gijs D. Mulders, Enrico Ragusa, Steph Sallum, Yangfan Shi, Marco Tazzari, Taichi Uyama, Kevin Wagner, David J. Wilner, Jerry W. Xuan
Summary: This paper presents high-resolution observations of dust continuum and CO line emission towards the disk around the M3.5 star 2MASSJ04124068+2438157 using the Atacama Large Millimeter/submillimeter Array. The dust disk consists of two narrow rings with Gaussian sigma widths, and the outer ring suggests dust trapping in a radial pressure bump. The disk's physical structure and accretion properties favor planet-disk interaction as the explanation for the observed morphology.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Christopher C. Stark, Bin Ren, Meredith A. MacGregor, Ward S. Howard, Spencer A. Hurt, Alycia J. Weinberger, Glenn Schneider, Elodie Choquet
Summary: HD 53143 is a mature Sun-like star with a cold outer ring of planetesimals near 90 au. The cold disk around HD 53143 appears as disconnected arcs, with no forward-scattering side detected. New observations show that the forward-scattering side of the disk remains undetected. By fitting the observations with an optically thin disk model, it is found that an unconstrained orientation results in an unphysical edge-on orientation.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Kyle Franson, Brendan P. Bowler, Yifan Zhou, Tim D. Pearce, Daniella C. Bardalez C. Gagliuffi, Lauren I. Biddle, Timothy D. Brandt, Justin R. Crepp, Trent J. Dupuy, Jacqueline Faherty, Rebecca Jensen-Clem, Marvin Morgan, Aniket Sanghi, Christopher A. Theissen, Quang H. Tran, Trevor N. Wolf
Summary: We report the direct-imaging discovery of a giant planet orbiting the young star AF Lep, with precise constraints on its dynamical mass, semimajor axis, and eccentricity. The host star also has a debris disk, but it is unlikely to be sculpted by the planet AF Lep b, suggesting the possibility of additional planets in the system. This discovery highlights the potential of using astrometric accelerations to find and characterize long-period planets.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Yiting Li, Timothy D. Brandt, G. Mirek Brandt, Qier An, Kyle Franson, Trent J. Dupuy, Minghan Chen, Rachel Bowens-Rubin, Briley L. Lewis, Brendan P. Bowler, Aidan Gibbs, Rocio Kiman, Jacqueline Faherty, Thayne Currie, Rebecca Jensen-Clem, Hengyue Zhang, Ezequiel Contreras-Martinez, Michael P. Fitzgerald, Benjamin A. Mazin, Maxwell Millar-Blanchaer
Summary: We report the discovery of a substellar companion to HD 176535 A, a well-measured brown dwarf. The companion was found through direct imaging survey and has a dynamical mass of 65.9(-1.7)(+2.0) M-Jup.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Logan A. Pearce, Jared R. Males, Sebastiaan Y. Haffert, Laird M. Close, Joseph D. Long, Avalon L. McLeod, Justin M. Knight, Alexander D. Hedglen, Alycia J. Weinberger, Olivier Guyon, Maggie Kautz, Kyle Van Gorkom, Jennifer Lumbres, Lauren Schatz, Alex Rodack, Victor Gasho, Jay Kueny, Warren Foster, Katie M. Morzinski, Philip M. Hinz
Summary: We confirm the existence of a new stellar companion, HIP 67506 C, to HIP 67506 A. The confirmation was based on several indirect signals, including astrometric acceleration, motion anomaly, and overluminosity. We used MagAO-X to characterize the companion and re-evaluated the primary star, HIP 67506 A. Additionally, we clarified that the previously identified companion, HIP 67506 B, is a distant unassociated background star.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)