Article
Astronomy & Astrophysics
Mate Szilagyi, Maria Kun, Peter Abraham
Summary: In this study, a new census of candidate pre-main-sequence stars in the Cepheus flare star-forming region is presented based on Gaia EDR3 data. The 3D structure of the star-forming complex and the distribution of tangential velocities of young stars were studied, revealing three kinematic subgroups and confirming the scenario of propagating star formation. New moving groups and scattered pre-main-sequence populations were identified in addition to the main pre-main-sequence star population, with implications for star-forming regions associated with the Galactic local arm.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
P. Saha, G. Maheswar, B. Mathew, U. S. Kamath
Summary: The presence of additional Herbig Ae/Be (HAeBe) candidates in the Cepheus Flare center suggests prevalent star formation in LDN clouds. Kinematically associated young sources were identified based on Gaia DR2 data, indicating the ongoing low-mass star formation in the region.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Mate Szilagyi, Maria Kun, Peter abraham, Gabor Marton
Summary: Using Gaia DR3 data, this study investigates the structure and kinematics of the Cepheus OB2 association and characterizes its star formation history, with particular focus on the Cepheus Bubble. Thirteen stellar groups belonging to Cep OB2 are identified using a clustering algorithm, with four older groups located inside the bubble and younger groups found on the periphery. The tangential velocities suggest different formation mechanisms, with some groups born in an expanding system of star-forming clouds and others formed due to collision with the expanding bubble.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Zhiyuan Ren, Lei Zhu, Hui Shi, Nannan Yue, Di Li, Qizhou Zhang, Diego Mardones, Jingwen Wu, Sihan Jiao, Shu Liu, Gan Luo, Jinjin Xie, Chao Zhang, Xuefang Xu
Summary: The study of filamentary structures in the Orion A molecular cloud region OMC-3 MMS-7 using ALMA and SMA observations revealed close associations with star-forming cores. The analysis of N2H+ emission showed dense filaments intersecting at the central core MMS-7, indicating an inward motion towards pre-stellar core formation. This filament contraction may lead to the generation of intermediate-mass or high-mass stars, with a steady and less intense process compared to global spherical collapses.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Hannah E. Ambrose, Yancy L. Shirley, Samantha Scibelli
Summary: Recent observations show that organic molecules are common in starless and pre-stellar cores, and deuterated organic molecules have not been well studied during the starless phase. An investigation of deuterated methanol towards 12 cores in the Taurus molecular cloud region indicates that deuterium fractionation of organic molecules during the starless phase might be more easily detectable than previously thought.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
R. Carini, K. Biazzo, G. De Marchi, N. Panagia, G. Beccari, E. Brocato
Summary: In this study, the accretion properties of low-mass pre-main sequence stars in the LH 91 association within the Large Magellanic Clouds are investigated using optical multiband photometry obtained with the Hubble Space Telescope. The age distribution suggests a period of active star formation ranging from a few million years up to approximately 60 million years, with a gap between 5 million years and 10 million years. The masses of the pre-main sequence candidates range from 0.2 solar masses to 1.0 solar mass, with an average of approximately 0.80 solar mass. The results also show variations in accretion luminosity and mass accretion rate with the age of the stars. Comparison with LH 95 reveals that LH 91 appears to be in a more evolved stage. Additionally, the pre-main sequence candidates are found to be uniformly distributed without any evidence of clumps around more massive stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Hong-Li Liu, Anandmayee Tej, Tie Liu, Patricio Sanhueza, Sheng-Li Qin, Jinhua He, Paul F. Goldsmith, Guido Garay, Sirong Pan, Kaho Morii, Shanghuo Li, Amelia Stutz, Ken'ichi Tatematsu, Feng-Wei Xu, Leonardo Bronfman, Anindya Saha, Namitha Issac, Tapas Baug, L. Viktor Toth, Lokesh Dewangan, Ke Wang, Jianwen Zhou, Chang Won Lee, Dongting Yang, Anxu Luo, Xianjin Shen, Yong Zhang, Yue-Fang Wu, Zhiyuan Ren, Xun-Chuan Liu, Archana Soam, Siju Zhang, Qiu-Yi Luo
Summary: We present a statistical study of 17 hub-filament-system (HFS) clouds of high-mass star formation using high-angular resolution ALMA data. The study reveals an evolutionary trend of increasing mass and mass surface density from the IR-dark to IR-bright stage. Mass-segregated clusters of YSOs are observed in both IR-dark and IR-bright HFSs, with massive YSOs located in the hub and low-mass YSOs distributed over larger areas. Outflow feedback preferentially escapes through inter-filamentary diffuse cavities, suggesting a limited effect on HFS disruption and high-mass star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
K. Giers, S. Spezzano, F. Alves, P. Caselli, E. Redaelli, O. Sipilae, M. Ben Khalifa, L. Wiesenfeld, S. Brunken, L. Bizzocchi
Summary: This study investigates the distribution of deuterated molecules in the pre-stellar core L1544 using emission maps of cyclopropenylidene. The results show that the highest deuterium fractions are found near the dust peak at the center of L1544, indicating a more efficient deuteration process in the core's center. The study also suggests the presence of carbon-chain molecules at high densities.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
M. Vlasblom, G. De Marchi
Summary: We studied the young stellar populations in the NGC 299 cluster in the Small Magellanic Cloud using observations obtained with the Hubble Space Telescope in three different bands. We identified pre-main-sequence (PMS) objects still undergoing active accretion and determined their physical stellar parameters. Our findings suggest the existence of two populations of PMS stars with different ages and support the idea that the metallicity and density of the forming environment can affect the star formation process. The spatial distribution of massive stars and PMS objects in the cluster suggests a possible dispersal of the latter due to two-body relaxation.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
O. L. Ryabukhina, M. S. Kirsanova, C. Henkel, D. S. Wiebe
Summary: In this study, observations and astrochemical modeling were used to investigate the physical properties, collapse features, and chemical ages of dense clumps in an interstellar filament. The results suggest rapid interstellar matter accumulation and collapse over a time scale of approximately 10(5) years, which is important for understanding the evolution of interstellar matter.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Rin Yamada, Yasuo Fukui, Hidetoshi Sano, Kengo Tachihara, John H. Bieging, Rei Enokiya, Atsushi Nishimura, Shinij Fujita, Mikito Kohno, Kisetsu Tsuge
Summary: In this study, a kinematical analysis of the molecular gas in the Sh2-233 region was conducted, revealing the presence of a filamentary cloud and two dense cloud cores. The collision between these two clouds resulted in the compression of the gas, forming the filament and the dense cores. One of the dense cores is associated with a high-mass protostellar candidate. The findings suggest that cloud-cloud collision plays a crucial role in the formation of compact high-mass dense cores.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Swagat R. Das, Jessy Jose, Manash R. Samal, Shaobo Zhang, Neelam Panwar
Summary: This study tested various star formation scaling relations and found correlations between Sigma(SFR) and Sigma(gas) in molecular cloud clumps, with some consistency in results among different models. However, due to uncertainties in input observables, it is not possible to accurately differentiate between the various models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Glen H. Hunter, Paul C. Clark, Simon C. O. Glover, Ralf S. Klessen
Summary: In this study, the impact of collision speed, magnetic field inclination, and resolution on the star formation rate (SFR) in cloud-cloud collisions is investigated. A factor of 2-3 increase in the SFR is found compared to no collision simulations, with high collisional velocities, parallel magnetic field and collision axis orientation, and lower resolution leading to earlier star formation. The alignment of velocity and magnetic field is consistent in low-density environments but becomes more perpendicular as density increases, indicating the compression of the magnetic field by collapsing gas.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Sunay Ibryamov, Gabriela Zidarova, Evgeni Semkov, Stoyanka Peneva
Summary: The paper presents the results of long-term optical CCD photometric observations of 13 pm-main-sequence stars in the active star-forming region of Cepheus OB3, revealing strong photometric variability in all investigated stars. This study fills a gap in the literature regarding photometric observations of these stars and contributes to a broader program of photometric study of pm-main-sequence stars in active star-forming regions.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
S. Ekta, G. Maheswar, D. Sami
Summary: This study estimated the motions of four clouds in the Cepheus Flare region and studied their relationship with the magnetic field and clump orientations. The results showed that the motions of the clouds were offset by approximately 30 degrees with respect to the magnetic fields, except for one cloud. The clump orientations were randomly distributed with respect to the magnetic fields in most clouds. Additionally, there was a correlation between the motion of the clouds and the orientations of the clumps.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Scott J. Kenyon, Benjamin C. Bromley
Summary: Based on numerical calculations, the long-term evolution of circumbinary debris from the Pluto-Charon giant impact is studied. Most solids are ejected from the system due to dynamical interactions with Pluto and Charon over timescales of 100-1000 yr. The resulting circumbinary disk in the Pluto-Charon orbital plane is more extended compared to narrow rings produced from other collision debris, but may be less suitable for producing small circumbinary satellites.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Benjamin C. Bromley, Austin Leonard, Amanda Quintanilla, Austin J. King, Chris Mann, Scott J. Kenyon
Summary: This study revisits the problem of identifying faint echoes in postflare light curves, focusing on circumstellar dust detection. By applying algorithms to light curves from over 2100 stars observed by NASA's Kepler mission and grouping stars according to IR excess, researchers found that the average mass of dust around the stars cannot exceed certain limits. Stars with strong IR excess showed greater mass limits, suggesting that echoes may be more easily detected in these cases.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Andrew Swan, Scott J. Kenyon, Jay Farihi, Erik Dennihy, Boris T. Gansicke, J. J. Hermes, Carl Melis, Ted von Hippel
Summary: WD0145+234 is a white dwarf accreting metals from a circumstellar disc, with a significant increase in 3-5 μm flux since 2018 that began to decrease by late 2019. Stochastic brightening events during the decline suggest liberation of dust during collisional evolution of circumstellar solids. Emission lines from circumstellar gas support the idea of white dwarf debris discs as sites of collisional gas and dust production.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Joan R. Najita, Scott J. Kenyon, Benjamin C. Bromley
Summary: This study explores the potential connection between protoplanetary disk rings, planets, and debris disks through new calculations, which suggest that solid rings with high initial masses and modest planetesimal formation efficiencies may evolve into known cold debris disks. These findings support the possibility that large protoplanetary disk rings evolve into cold debris disks.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Laura Flagg, Christopher M. Johns-Krull, Kevin France, Gregory Herczeg, Joan Najita, John M. Carpenter, Scott J. Kenyon
Summary: Using HST-COS far-UV spectra, warm molecular hydrogen has been discovered in the TWA 7 system, indicating that TWA 7 may be accreting at very low levels and retaining a reservoir of gas in the near circumstellar environment.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Scott J. Kenyon, Benjamin C. Bromley
Summary: The study discusses 500 numerical n-body calculations aimed at constraining the masses and bulk densities of four Pluto's moons. Comparisons favor methods based on the theory of Lee & Peale and suggest that Styx and Kerberos may have bulk densities comparable with water ice.
ASTRONOMICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Laura Flagg, Christopher M. Johns-Krull, Kevin France, Gregory Herczeg, Joan Najita, Allison Youngblood, Adolfo Carvalho, John Carptenter, Scott J. Kenyon, Elisabeth Newton, Keighley Rockcliffe
Summary: Molecular hydrogen, which is abundant in the galaxy, plays vital roles in planets, their circumstellar environments, and host stars. In this study, the presence of molecular hydrogen in the AU Mic system is confirmed through high-resolution FUV spectra. The gas temperature is estimated to be 1000-2000K, and the emission is likely produced in the star instead of the disk or the planet.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Benjamin C. Bromley, Scott J. Kenyon
Summary: The magnetic field of a host star can affect the orbit of its stellar partner, planet, or asteroid if the orbiting body is magnetic or electrically conducting. When an orbiting permanent magnet is close to the stellar host, it will be drawn towards it due to the dipole-dipole interaction. Although the observed magnetic fields in systems are generally too weak to cause a merger event, they may be strong enough in some compact binaries to result in measurable orbital precession. When the orbiting body is a conductor, the stellar field induces a time-varying magnetic dipole moment, which can lead to eccentricity pumping and resonance trapping. The challenge is that the orbiting body must be close to the star, competing with tidal forces and intense stellar radiation.
ASTRONOMICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Joan R. Najita, Scott J. Kenyon
Summary: The formation of terrestrial planets like Earth through late-stage giant impacts may not produce the anticipated visible signpost of warm dusty debris due to transport mechanisms that can erase the debris signature. The regeneration of a tenuous gas disk or the powerful stellar wind can effectively remove the warm debris. This suggests that terrestrial planets may quietly assemble without attracting much attention or undergo early formation without late-stage giant impacts.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Benjamin C. Bromley, Scott J. Kenyon
Summary: The method allows fast and approximate characterization of satellite orbits around a central binary, distinguish free eccentricity from oscillatory modes driven by the central binary's gravitational potential. By applying the method to numerical simulations of various systems, it resolves relative speeds between small bodies slow enough to promote mergers and growth.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Scott J. Kenyon, Benjamin C. Bromley
PLANETARY SCIENCE JOURNAL
(2020)
Article
Astronomy & Astrophysics
Benjamin C. Bromley, Scott J. Kenyon
ASTRONOMICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Warren R. Brown, Mukremin Kilic, Alekzander Kosakowski, Jeff J. Andrews, Craig O. Heinke, Marcel A. Agueros, Fernando Camilo, A. Gianninas, J. J. Hermes, Scott J. Kenyon
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Benjamin C. Bromley, Scott J. Kenyon
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
Scott J. Kenyon, Benjamin C. Bromley
ASTRONOMICAL JOURNAL
(2019)