Search

Your search keyword '"Lund, Mikkel"' showing total 22 results
Start Over Author "Lund, Mikkel" Journal monthly notices of the royal astronomical society
22 results on '"Lund, Mikkel"'

1. Three low-mass companions around aged stars discovered by TESS

Author

Lin, Zitao, primary, Gan, Tianjun, additional, Wang, Sharon X, additional, Shporer, Avi, additional, Rabus, Markus, additional, Zhou, George, additional, Psaridi, Angelica, additional, Bouchy, François, additional, Bieryla, Allyson, additional, Latham, David W, additional, Mao, Shude, additional, Stassun, Keivan G, additional, Hellier, Coel, additional, Howell, Steve B, additional, Ziegler, Carl, additional, Caldwell, Douglas A, additional, Clark, Catherine A, additional, Collins, Karen A, additional, Curtis, Jason L, additional, Faherty, Jacqueline K, additional, Gnilka, Crystal L, additional, Grunblatt, Samuel K, additional, Jenkins, Jon M, additional, Johnson, Marshall C, additional, Law, Nicholas, additional, Lendl, Monika, additional, Littlefield, Colin, additional, Lund, Michael B, additional, Lund, Mikkel N, additional, Mann, Andrew W, additional, McDermott, Scott, additional, Mishra, Lokesh, additional, Mounzer, Dany, additional, Paegert, Martin, additional, Pritchard, Tyler, additional, Ricker, George R, additional, Seager, Sara, additional, Srdoc, Gregor, additional, Sun, Qinghui, additional, Tang, Jiaxin, additional, Udry, Stéphane, additional, Vanderspek, Roland, additional, Watanabe, David, additional, Winn, Joshua N, additional, and Yu, Jie, additional

Published
2023
Full Text
View/download PDF

3. The odd bunch: chrono-chemo-dynamics of sixteen unusual stars from Kepler.

Author

Alencastro Puls, Arthur, Casagrande, Luca, Monty, Stephanie, Yong, David, Liu, Fan, Stello, Dennis, and Lund, Mikkel N

Subjects
GALACTIC evolution, RED giants, ORBITS (Astronomy), CHEMICAL models, PARALLAX, SUPERGIANT stars, AGE of stars
Abstract

In this study we combine asteroseismic, spectroscopic, and kinematic information to perform a detailed analysis of a sample of 16 stars from the Kepler field. Our selection focuses on stars that appear to contradict Galactic chemical evolution models: young and α-rich, old and metal-rich, as well as other targets with unclear classification in past surveys. Kinematics are derived from Gaia DR3 parallaxes and proper motions, and high-resolution spectra from HIRES/Keck are used to calculate chemical abundances for over 20 elements. This information is used to perform careful checks on asteroseismic masses and ages derived via grid-based modelling. Among the seven stars previously classified as young and α-rich, only one seems to be an unambiguously older object masking its true age. We confirm the existence of two very old (≥11 Gyr), super metal-rich (≥0.1 dex) giants. These two stars have regular thin disc chemistry and in-plane solar circle orbits that fit well in the picture of radial migration via the churning mechanism. The alternative explanation that these stars have younger ages would require mass-loss rates that strongly increase with increasing metallicity. Finally, we suggest further investigations to explore the suitability of Zn as a chemical clock in red giants. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

5. TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

Author

Addison, Brett C, primary, Wright, Duncan J, additional, Nicholson, Belinda A, additional, Cale, Bryson, additional, Mocnik, Teo, additional, Huber, Daniel, additional, Plavchan, Peter, additional, Wittenmyer, Robert A, additional, Vanderburg, Andrew, additional, Chaplin, William J, additional, Chontos, Ashley, additional, Clark, Jake T, additional, Eastman, Jason D, additional, Ziegler, Carl, additional, Brahm, Rafael, additional, Carter, Bradley D, additional, Clerte, Mathieu, additional, Espinoza, Néstor, additional, Horner, Jonathan, additional, Bentley, John, additional, Jordán, Andrés, additional, Kane, Stephen R, additional, Kielkopf, John F, additional, Laychock, Emilie, additional, Mengel, Matthew W, additional, Okumura, Jack, additional, Stassun, Keivan G, additional, Bedding, Timothy R, additional, Bowler, Brendan P, additional, Burnelis, Andrius, additional, Blanco-Cuaresma, Sergi, additional, Collins, Michaela, additional, Crossfield, Ian, additional, Davis, Allen B, additional, Evensberget, Dag, additional, Heitzmann, Alexis, additional, Howell, Steve B, additional, Law, Nicholas, additional, Mann, Andrew W, additional, Marsden, Stephen C, additional, Matson, Rachel A, additional, O’Connor, James H, additional, Shporer, Avi, additional, Stevens, Catherine, additional, Tinney, C G, additional, Tylor, Christopher, additional, Wang, Songhu, additional, Zhang, Hui, additional, Henning, Thomas, additional, Kossakowski, Diana, additional, Ricker, George, additional, Sarkis, Paula, additional, Schlecker, Martin, additional, Torres, Pascal, additional, Vanderspek, Roland, additional, Latham, David W, additional, Seager, Sara, additional, Winn, Joshua N, additional, Jenkins, Jon M, additional, Mireles, Ismael, additional, Rowden, Pam, additional, Pepper, Joshua, additional, Daylan, Tansu, additional, Schlieder, Joshua E, additional, Collins, Karen A, additional, Collins, Kevin I, additional, Tan, Thiam-Guan, additional, Ball, Warrick H, additional, Basu, Sarbani, additional, Buzasi, Derek L, additional, Campante, Tiago L, additional, Corsaro, Enrico, additional, González-Cuesta, L, additional, Davies, Guy R, additional, de Almeida, Leandro, additional, do Nascimento, Jose-Dias, additional, García, Rafael A, additional, Guo, Zhao, additional, Handberg, Rasmus, additional, Hekker, Saskia, additional, Hey, Daniel R, additional, Kallinger, Thomas, additional, Kawaler, Steven D, additional, Kayhan, Cenk, additional, S. Kuszlewicz, James, additional, Lund, Mikkel N, additional, Lyttle, Alexander, additional, Mathur, Savita, additional, Miglio, Andrea, additional, Mosser, Benoit, additional, Nielsen, Martin B, additional, Serenelli, Aldo M, additional, Aguirre, Victor Silva, additional, and Themeßl, Nathalie, additional

Published
2020
Full Text
View/download PDF

6. K2-280 b – a low density warm sub-Saturn around a mildly evolved star

Author

Nowak, Grzegorz, primary, Palle, Enric, additional, Gandolfi, Davide, additional, Deeg, Hans J, additional, Hirano, Teruyuki, additional, Barragán, Oscar, additional, Kuzuhara, Masayuki, additional, Dai, Fei, additional, Luque, Rafael, additional, Persson, Carina M, additional, Fridlund, Malcolm, additional, Johnson, Marshall C, additional, Korth, Judith, additional, Livingston, John H, additional, Grziwa, Sascha, additional, Mathur, Savita, additional, Hatzes, Artie P, additional, Prieto-Arranz, Jorge, additional, Nespral, David, additional, Hidalgo, Diego, additional, Hjorth, Maria, additional, Albrecht, Simon, additional, Van Eylen, Vincent, additional, Lam, Kristine W F, additional, Cochran, William D, additional, Esposito, Massimiliano, additional, Csizmadia, Szilárd, additional, Guenther, Eike W, additional, Kabath, Petr, additional, Blay, Pere, additional, Brahm, Rafael, additional, Jordán, Andrés, additional, Espinoza, Néstor, additional, Rojas, Felipe, additional, Casasayas Barris, Núria, additional, Rodler, Florian, additional, Alonso Sobrino, Roi, additional, Cabrera, Juan, additional, Carleo, Ilaria, additional, Chaushev, Alexander, additional, de Leon, Jerome, additional, Eigmüller, Philipp, additional, Endl, Michael, additional, Erikson, Anders, additional, Fukui, Akihiko, additional, Georgieva, Iskra, additional, González-Cuesta, Lucía, additional, Knudstrup, Emil, additional, Lund, Mikkel N, additional, Montañes Rodríguez, Pilar, additional, Murgas, Felipe, additional, Narita, Norio, additional, Niraula, Prajwal, additional, Pätzold, Martin, additional, Rauer, Heike, additional, Redfield, Seth, additional, Ribas, Ignasi, additional, Skarka, Marek, additional, Smith, Alexis M S, additional, and Subjak, Jano, additional

Published
2020
Full Text
View/download PDF

7. The subgiant HR 7322 as an asteroseismic benchmark star

Author

Stokholm, Amalie, primary, Nissen, Poul Erik, additional, Silva Aguirre, Víctor, additional, White, Timothy R, additional, Lund, Mikkel N, additional, Mosumgaard, Jakob Rørsted, additional, Huber, Daniel, additional, and Jessen-Hansen, Jens, additional

Published
2019
Full Text
View/download PDF

10. aims– a new tool for stellar parameter determinations using asteroseismic constraints

Author

Rendle, Ben M, primary, Buldgen, Gaël, additional, Miglio, Andrea, additional, Reese, Daniel, additional, Noels, Arlette, additional, Davies, Guy R, additional, Campante, Tiago L, additional, Chaplin, William J, additional, Lund, Mikkel N, additional, Kuszlewicz, James S, additional, Scott, Laura J A, additional, Scuflaire, Richard, additional, Ball, Warrick H, additional, Smetana, Jiri, additional, and Nsamba, Benard, additional

Published
2019
Full Text
View/download PDF

14. Weighing in on the masses of retired A stars with asteroseismology: K2 observations of the exoplanet-host star HD 212771

Author

Campante, Tiago L., primary, Veras, Dimitri, additional, North, Thomas S. H., additional, Miglio, Andrea, additional, Morel, Thierry, additional, Johnson, John A., additional, Chaplin, William J., additional, Davies, Guy R., additional, Huber, Daniel, additional, Kuszlewicz, James S., additional, Lund, Mikkel N., additional, Cooke, Benjamin F., additional, Elsworth, Yvonne P., additional, Rodrigues, Thaíse S., additional, and Vanderburg, Andrew, additional

Published
2017
Full Text
View/download PDF

16. Helium abundance in a sample of cool stars: measurements from asteroseismology.

Author

Verma, Kuldeep, Raodeo, Keyuri, Basu, Sarbani, Silva Aguirre, Víctor, Mazumdar, Anwesh, Mosumgaard, Jakob Rørsted, Lund, Mikkel N, and Ranadive, Pritesh

Subjects
HEAVY elements, STELLAR oscillations, STELLAR evolution, NANOPARTICLES, IONIZATION energy
Abstract

The structural stratification of a solar-type main-sequence star primarily depends on its mass and chemical composition. The surface heavy element abundances of the solar-type stars are reasonably well determined using conventional spectroscopy; however, the second most abundant element helium is not. This is due to the fact that the envelope temperature of such stars is not high enough to excite helium. Since the helium abundance of a star affects its structure and subsequent evolution, the uncertainty in the helium abundance of a star makes estimates of its global properties (mass, radius, age etc.) uncertain as well. The detections of the signatures of the acoustic glitches from the precisely measured stellar oscillation frequencies provide an indirect way to estimate the envelope helium content. We use the glitch signature caused by the ionization of helium to determine the envelope helium abundance of 38 stars in the Kepler seismic LEGACY sample. Our results confirm that atomic diffusion does indeed take place in solar-type stars. We use the measured surface abundances in combination with the settling predicted by the stellar models to determine the initial abundances. The initial helium and metal mass fractions have subsequently been used to get the preliminary estimates of the primordial helium abundance, Y p = 0.244 ± 0.019, and the Galactic enrichment ratio, Δ Y /Δ Z  = 1.226 ± 0.849. Although the current estimates have large errorbars due to the limited sample size, this method holds great promises to determine these parameters precisely in the era of upcoming space missions. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

17. Asteroseismology of the Hyades with K2: first detection of main-sequence solar-like oscillations in an open cluster

Author

Lund, Mikkel N., primary, Basu, Sarbani, additional, Silva Aguirre, Víctor, additional, Chaplin, William J., additional, Serenelli, Aldo M., additional, García, Rafael A., additional, Latham, David W., additional, Casagrande, Luca, additional, Bieryla, Allyson, additional, Davies, Guy R., additional, Viani, Lucas S., additional, Buchhave, Lars A., additional, Miglio, Andrea, additional, Soderblom, David R., additional, Valenti, Jeff A., additional, Stefanik, Robert P., additional, and Handberg, Rasmus, additional

Published
2016
Full Text
View/download PDF

19. A simple model to describe intrinsic stellar noise for exoplanet detection around red giants.

Author

North, Thomas S. H., Chaplin, William J., Gilliland, Ronald L., Huber, Daniel, Campante, Tiago L., Handberg, Rasmus, Lund, Mikkel N., Veras, Dimitri, Kuszlewicz, James S., and Farr, Will M.

Subjects
STELLAR granulation, DETECTION of extrasolar planets, RED giants, SEISMOLOGY, STELLAR luminosity function
Abstract

In spite of the huge advances in exoplanet research provided by the NASA Kepler Mission, there remain only a small number of transit detections around evolved stars. Here, we present a reformulation of the noise properties of red-giant stars, where the intrinsic stellar granulation and the stellar oscillations described by asteroseismology play a key role. The new noise model is a significant improvement on the current Kepler results for evolved stars. Our noise model may be used to help understand planet detection thresholds for the ongoing K2 and upcoming TESS missions, and serve as a predictor of stellar noise for these missions. As an application of our noise model, we explore the minimum detectable planet radii for red giant stars, and find that Neptune-sized planets should be detectable around low-luminosity red giant branch stars. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

20. EPIC 201585823, a rare triple-mode RR Lyrae star discovered in K2 mission data.

Author

Kurtz, Donald W., Bowman, Dominic M., Ebo, Simon J., Moskalik, Paweł, Handberg, Rasmus, and Lund, Mikkel N.

Subjects
RR Lyrae stars, DATA analysis, GALACTIC bulges, ASTRONOMICAL observations, SUBHARMONIC functions, STELLAR oscillations
Abstract

We have discovered a new, rare triple-mode RR Lyr star, EPIC 201585823, in the Kepler K2 mission Campaign 1 data. This star pulsates primarily in the fundamental and firstovertone radial modes, and, in addition, a third non-radial mode. The ratio of the period of the non-radial mode to that of the first-overtone radial mode, 0.616 285, is remarkably similar to that seen in 11 other triple-mode RR Lyr stars, and in 260 RRc stars observed in the Galactic bulge. This systematic character promises new constraints on RR Lyr star models. We detected subharmonics of the non-radial mode frequency, which are a signature of period doubling of this oscillation; we note that this phenomenon is ubiquitous in RRc and RRd stars observed from space, and from ground with sufficient precision. The nonradial mode and subharmonic frequencies are not constant in frequency or in amplitude. The amplitude spectrum of EPIC 201585823 is dominated by many combination frequencies among the three interacting pulsation mode frequencies. Inspection of the phase relationships of the combination frequencies in a phasor plot explains the 'upward' shape of the light curve. We also found that raw data with custom masks encompassing all pixels with significant signal for the star, but without correction for pointing changes, is best for frequency analysis of this star, and, by implication, other RR Lyr stars observed by the K2 mission. We compare several pipeline reductions of the K2 mission data for this star. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results