Article
Astronomy & Astrophysics
D. Baroch, J. C. Morales, I Ribas, V. J. S. Bejar, S. Reffert, C. Cardona Guillen, A. Reiners, J. A. Caballero, A. Quirrenbach, P. J. Amado, G. Anglada-Escude, J. Colome, M. Cortes-Contreras, S. Dreizler, D. Galadi-Enriquez, A. P. Hatzes, S. Jeffers, Th Henning, E. Herrero, A. Kaminski, M. Kuerster, M. Lafarga, N. Lodieu, M. J. Lopez-Gonzalez, D. Montes, E. Palle, M. Perger, D. Pollacco, C. Rodriguez-Lopez, E. Rodriguez, A. Rosich, P. Schoefer, A. Schweitzer, Y. Shan, L. Tal-Or, M. Zechmeister
Summary: During the CARMENES survey, nine multiple stellar systems were studied, with the results showing the detection of several new systems with long periods and low radial-velocity amplitudes. The study derived radial velocities of the stars using cross-correlation techniques and template matching, combining data from various sources to improve analysis. The significant findings included the determination of spectroscopic orbits of nine systems, with insights into potential brown dwarfs and white dwarfs in close binary orbits.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Simon Blouin, Siyi Xu
Summary: Recent studies show that the mass accretion rates of cool, old white dwarfs do not significantly decrease over several billion years of cooling time, indicating the need for mechanisms to consistently deliver planetesimals inside the Roche radius of white dwarfs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
B. Zuckerman
Summary: With recent satellite data and a few assumptions, it is now possible to begin to observationally constrain the frequency of space-based civilizations in our Milky Way Galaxy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Sophie Dubber, Beth Biller, Loic Albert, Michael Liu, Jessy Jose, Zhoujian Zhang, Wen-Ping Chen, Bhavana Lalchand, Belinda Damian, Tanvi Sharma, Katelyn Allers
Summary: We have spectroscopically confirmed nine M5 or later Serpens Core candidate members using CFHT WIRCam photometry and IRTF SpeX spectroscopy. The latest of these candidates is best fit by an L0 spectral standard, suggesting a mass of about 0.01-0.035M (solar mass). If confirmed as cluster members, they would be among the lowest mass objects ever discovered in the Serpens Core. We performed analysis on the physical properties of the sample and discussed the likely membership of the candidate Serpens Core members.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
C. S. Jeffery, K. Werner, D. Kilkenny, B. Miszalski, I Monageng, E. J. Snowdon
Summary: The Southern African Large Telescope survey has discovered and analyzed eight new very hot white dwarfs and pre-white dwarfs, with effective temperatures exceeding 100,000 K, including two PG1159 stars, one DO white dwarf, three O(He) stars, and two O(H) stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
S. Dalal, F. Kiefer, G. Hebrard, J. Sahlmann, S. G. Sousa, T. Forveille, X. Delfosse, L. Arnold, N. Astudillo-Defru, X. Bonfils, I Boisse, F. Bouchy, V Bourrier, B. Brugger, P. Cortes-Zuleta, M. Deleuil, D. S. Demangeon, R. F. Diaz, N. C. Hara, N. Heidari, M. J. Hobson, T. Lopez, C. Lovis, Martioli, L. Mignon, O. Mousis, C. Moutou, J. Rey, A. Santerne, N. C. Santos, Segransan, P. A. Strom, S. Udry
Summary: This study identifies and characterizes 6 cool Jupiters, 3 brown dwarf candidates, and 16 low-mass stellar companions using radial velocity surveys. The discovery of a new, highly eccentric cool Jupiter, BD+631405 b, adds to the diversity of substellar objects. The findings help constrain models of formation and evolution for substellar objects and low-mass stars.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
L. T. T. Soethe, S. O. Kepler
Summary: The study explores the formation of Extremely low-mass white dwarfs (ELM WDs) in binary systems using the treatment of convection and rotation boosted magnetic braking. By calculating evolutionary sequences, ELM models in the range 0.15-0.27 M-circle dot are obtained from a broad range of initial orbital periods, showing the potential formation of ultracompact X-ray binaries (UCXBs) and wide-orbit binary millisecond pulsars. The relation between mass and orbital period obtained is consistent with observational data from He WD companions to pulsars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Samuel Pearson, Aleks Scholz, Paula S. Teixeira, Koraljka Muzic, Victor Almendros-Abad
Summary: Based on spectroscopic observations of 68 candidates in NGC 2264, researchers confirmed 13 brown dwarfs and 19 M-type stars, with ages predominantly younger than the known cluster population, indicating distinct formation processes. The estimated total of 200-600 brown dwarfs in NGC 2264 suggests a star-to-brown dwarf ratio between 2.5:1 and 7.5:1, with a consistent substellar mass function slope of alpha = 0.43(-0.56)(+0.41) across various young clusters, indicating a uniformity in substellar mass functions within star-forming environments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Sophie Dubber, Beth Biller, Katelyn Allers, Jessy Jose, Loic Albert, Blake Pantoja, Clemence Fontanive, Michael Liu, Zhoujian Zhang, Wen-Ping Chen, Bhavana Lalchand, Belinda Damian, Tanvi Sharma
Summary: Using CFHT photometry and IRTF spectroscopy, low-mass candidate members of Serpens South and Serpens Core were identified using the W-band method. Young, low-mass Serpens candidate members were reported with masses less than 0.12 solar masses. Additionally, a binary system was discovered with components separated by approximately 45AU, each with spectral types and masses within a specific range. The analysis also discussed the impact of dust attenuation and reddened background stars on the reliability of the findings.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. Kosakowski, M. Kilic, W. R. Brown, P. Bergeron, T. Kupfer
Summary: The study presents the discovery of nine deeply eclipsing white dwarf candidates in the ZTF data, four of which were further investigated. Three systems were found to exhibit total eclipses in both ZTF and follow-up observations. It was revealed that all four systems contain a white dwarf with low-mass stellar companions. Additionally, the study identified 41 additional eclipsing WD+M candidates, including two new candidate short-period white dwarf-brown dwarf binaries.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Philippe Z. Yao, Eliot Quataert, Andy Goulding
Summary: Many double white dwarf mergers do not result in immediate thermonuclear explosions. The survivors of these mergers, particularly those involving double Carbon-Oxygen white dwarfs, can be observed for approximately 10,000 years and appear similar to massive white dwarfs evolving from extreme AGB stars. Detecting these merger remnants is easiest in galaxies with high-stellar masses and low star formation rates. Identifying them photometrically is challenging as they resemble He stars and post-outburst classical novae, but their unusual surrounding photoionized nebulae could be a promising technique for detection.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Samuel A. Beiler, Katelyn N. Allers, Michael Cushing, Jacqueline Faherty, Mark Marley, Andrew Skemer
Summary: We conducted a spectroscopic study on eight young L dwarfs in the L-band (2.98-3.96 μm) with spectral types ranging from L2 to L7. Our analysis focused on the evolution of the Q-branch of methane absorption feature and the impact of including the L-band data on atmoshperic models. We found that the Q-branch feature first appears between L3 and L6 and that the addition of the L band causes a drop in effective temperature and requires thick clouds and higher vertical mixing rates in the models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
Dorsa Majidi, John C. Forbes, Abraham Loeb
Summary: Under the right conditions, brown dwarfs that gain enough mass late in their lives to cross the hydrogen-burning limit will remain essentially brown dwarf-like. Accretion from AGB winds, aided by the wind Roche lobe overflow mechanism, is likely to produce a substantial population of observable overmassive brown dwarfs, while other mechanisms are also plausible.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Katja Stock, Dimitri Veras, Maxwell X. Cai, Rainer Spurzem, Simon Portegies Zwart
Summary: This study uses stellar cluster simulations to investigate the orbital architectures of planetary systems containing super-Earths. The results show that approximately 30% of simulated planets may generate sufficient eccentricities to pollute the atmospheres of white dwarfs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Alekzander Kosakowski, Mukremin Kilic, Warren Brown
Summary: The study utilized observations from the Apache Point Observatory and Gemini telescope to analyze the SDSS J082239.54+304857.19 binary system, revealing a low-mass DA white dwarf and a companion star. The research indicates that the temperature of the secondary star in the system is approximately 5200K, and a significant measurement of orbital decay due to gravitational waves is expected to be possible in 2023.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Paul A. Canton, Kurtis A. Williams, Mukremin Kilic, Michael Bolte
Summary: The study focuses on determining white dwarf masses and their progenitor star masses in the M67 cluster, providing crucial observational data for understanding and interpreting white dwarf populations and evolution. It also establishes the white dwarfs' positions on the initial-final mass relation with average values consistent with previous research, aiding in more precise modeling of the Galactic star formation rate.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Mukremin Kilic, A. Bedard, P. Bergeron
Summary: High-resolution spectroscopy is used to study two nearby white dwarfs with inconsistent spectroscopic and parallax distances, revealing SB2 systems that were previously undetected. By analyzing atmospheric parameters through composite model-atmosphere analysis, the study finds that the predicted period distribution of white dwarf binary systems is consistent with the observed population.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Mukremin Kilic, P. Bergeron, Simon Blouin, A. Bedard
Summary: This study analyzes the most massive white dwarf candidates in the Montreal White Dwarf Database, identifying a significant portion that are close to the maximum mass of CO core models and likely formed through binary mergers. Outliers in transverse velocity, magnetic properties, and rapid rotation indicate that a substantial number of ultramassive white dwarfs in the sample are likely products of mergers.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Mukremin Kilic, Warren R. Brown, A. Bedard, Alekzander Kosakowski
Summary: This study reports the discovery of two of the brightest detached binary white dwarfs with periods less than an hour, providing new gravitational-wave verification binaries for LISA. Precise system parameter constraints were obtained for these white dwarf systems, with one of them showing an intriguing feature where the companion to one white dwarf is more massive. This discovery suggests that follow-up observations of similar systems could lead to the identification of additional LISA verification binaries.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Article
Astronomy & Astrophysics
Mukremin Kilic, Alekzander Kosakowski, Adam G. Moss, P. Bergeron, Annamarie A. Conly
Summary: Researchers have discovered an isolated white dwarf with a spin period of 70 seconds, showing fast rotation, strong magnetic field, and unusual atmospheric composition, likely a remnant of a double white dwarf merger. These fast-spinning white dwarfs may influence the discovery of substellar and planetary mass companions around white dwarfs.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Proceedings Paper
Astronomy & Astrophysics
Breann N. Sitarski, Andrew Rakich, Hugo Chiquito, Wylie Rosenthal, Antonin H. Bouchez, William Schoenell, Bo Xin, Priscila Pires, Joel Nissen, P. Schurter, Richard T. Demers, Peter Thompson, Brian McLeod, Bijan Nemati, Glenn Brossus, Brian Walls, Heejoo Choi, Guillermo Gonzalez, David Nemati
Summary: This paper describes the current design of the Telescope Metrology System (TMS) for the Giant Magellan Telescope.
GROUND-BASED AND AIRBORNE TELESCOPES IX
(2022)
Proceedings Paper
Astronomy & Astrophysics
Brian A. McLeod, Antonin H. Bouchez, Daniel Catropa, Peyton Benac, Daniel Durusky, Jan Kansky, Derek Kopon, Grant Meiners, Stuart McMuldroch, William Podgorski, Richard T. Demers, Fernando Quiros-Pacheco, William Schoenell, Patricio Schurter, Breann Sitarski, Guillermo Gonzalez, Bijan Nemati, Diogo Slepetys
Summary: The Wide Field Phasing Testbed is designed to test the phasing and active optics systems of the Giant Magellan Telescope. It consists of optical relays with segmented and deformable mirrors representing the GMT M1 and M2 mirrors. The testbed can reproduce the telescope's field dependent aberrations and generate images corresponding to atmospheric conditions. The software allows connection to simulation systems and conforms to the planned interfaces of the GMT's control system.
GROUND-BASED AND AIRBORNE TELESCOPES IX
(2022)
Proceedings Paper
Astronomy & Astrophysics
Antonin H. Bouchez, Rodolphe Conan, Richard T. Demers, Brian A. McLeod, Fernando Quiros-Pacheco, Rodrigo Romano, Patricio Schurter, Breann Sitarski, Marcos A. Van Dam, Bo Xin
Summary: The wavefront control system of the Giant Magellan Telescope provides active optics control and optical turbulence correction for every instrument. The system design has been updated and prototypes of wavefront sensors are being developed, along with high-fidelity simulations.
ADAPTIVE OPTICS SYSTEMS VIII
(2022)
Proceedings Paper
Astronomy & Astrophysics
Daniel Catropa, Brian McLeod, Joseph D'Arco, Daniel Durusky, Jan Kansky, Stuart McMuldroch, William Podgorski, Matt Smith, Joseph Zajac, Antonin Bouchez, Brossus Glenn, Richard Demers, Fernando Quiros-Pacheco, Patricio Schurter, Breann Sitarski
Summary: The Wide Field Phasing Testbed (WFPT) is used to test the phasing and active optics systems of the Giant Magellan Telescope (GMT). It consists of segmented and deformable mirrors, with two segmented Piston-Tip-Tilt (PTT) mirror arrays used to reproduce discontinuous wavefront errors. The PTT arrays must have large stroke, high temporal stability, and narrow gaps to mimic the GMT pupil geometry.
ADAPTIVE OPTICS SYSTEMS VIII
(2022)
Proceedings Paper
Astronomy & Astrophysics
Richard Demers, Antonin Bouchez, Fernando Quiros-Pacheco, Patricio Schurter, Breann Sitarski, Marcos A. Van Dam, Dan Catropa, Jan Kansky, Brian McLeod, Stuart McMuldroch, Bill Podgorski, Laird Close, Victor Gasho, Sebastiaan Haffert, Alex Hedglen, Maggie Kautz, Jared Males, Guido Agapito, Nicolo Azzaroli, Luca Carbonaro, Anne-Laure Cheffot, Simone Esposito, Tommaso Lapucci, Enrico Pinna, Cedric Plantet, Alfio Puglisi, Fabio Rossi, Guillermo Gonzalez, Bijan Nemati
Summary: One of the greatest technical challenges of the Giant Magellan Telescope is the control of segment piston. A project is being executed to optimize and validate control strategies using testbeds. Significant progress has been made in the hardware design and preliminary testing.
ADAPTIVE OPTICS SYSTEMS VIII
(2022)
Proceedings Paper
Engineering, Mechanical
Brian A. McLeod, Peyton Benac, Grant Meiners, Daniel Catropa, Jan Kansky, William Podgorski, Derek Kopon
Summary: This passage describes the composition and alignment method of the Wide Field Phasing Testbed for the Giant Magellan Telescope, which involves the use of a Leica laser tracker and a 4D interferometer to accurately position and adjust the fold mirrors and OAPs. Custom software is used to read the optical prescription file, measure the fiducial SMR positions, perform coordinate transformations, and display real-time position errors.
ADVANCES IN OPTICAL AND MECHANICAL TECHNOLOGIES FOR TELESCOPES AND INSTRUMENTATION V
(2022)
Article
Astronomy & Astrophysics
Mukremin Kilic, P. Bergeron, Alekzander Kosakowski, Warren R. Brown, Marcel A. Agueros, Simon Blouin
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Alekzander Kosakowski, Mukremin Kilic, Warren R. Brown, Alexandros Gianninas
ASTROPHYSICAL 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)
