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Full-Text Articles in Physical Sciences and Mathematics
Multi-Site Photometry Of The Pulsating Herbig Ae Star V346 Ori, S Bernabei, T D. Oswalt
Multi-Site Photometry Of The Pulsating Herbig Ae Star V346 Ori, S Bernabei, T D. Oswalt
Aerospace, Physics, and Space Science Faculty Publications
Context. The study of pulsation in pre-main-sequence intermediate-mass stars represents an important tool for deriving information about fundamental stellar parameters and internal structure, as well as testing theoretical models. Interest in this class of variable stars has increased significantly during the last decade and about 30 members are presently known in the literature. Aims. After constructing the frequency spectrum of oscillations in V346 Ori, we apply asteroseismic tools to these data to estimate the intrinsic parameters (mass, luminosity, effective temperature) of V346 Ori and obtain information about its internal structure. Methods. CCD time-series photometry in the Johnson V filter was …
Spitzer Transit And Secondary Eclipse Photometry Of Gj 436b, Drake Deming, Joseph Patrick Harrington, Gregory P. Laughlin, Sara Seager, Sarah B. Navarro, William C. Bowman, Karen Horning
Spitzer Transit And Secondary Eclipse Photometry Of Gj 436b, Drake Deming, Joseph Patrick Harrington, Gregory P. Laughlin, Sara Seager, Sarah B. Navarro, William C. Bowman, Karen Horning
Aerospace, Physics, and Space Science Faculty Publications
We report the results of infrared (8 μm) transit and secondary eclipse photometry of the hot Neptune exoplanet, GJ 436b using Spitzer. The nearly photon-limited precision of these data allows us to measure an improved radius for the planet and to detect the secondary eclipse. The transit (centered at HJD p 2454280.78149 ± 0.00016) shows the flat-bottomed shape typical of infrared transits, and it precisely defines the planet-to-star radius ratio (±), independent of the stellar properties. However, we obtain the planetary radius, as well as the stellar mass and radius, by fitting to the transit curve simultaneously with an empirical …
Asteroseismology Of The Pg 1159 Star Pg 0122+200, Jianning Fu, Matt A. Wood
Asteroseismology Of The Pg 1159 Star Pg 0122+200, Jianning Fu, Matt A. Wood
Aerospace, Physics, and Space Science Faculty Publications
Context. The variable pre-white dwarf PG 1159 stars (GW Vir) are g-mode non-radial pulsators. Asteroseismology puts strong constraints on their global parameters and internal structure. PG 0122+200 defines the red edge of the instability strip and its evolutionary timescale is predicted to be dominated by neutrino emission. Its study offers the opportunity to better understand the instability mechanism and to validate the physics of the neutrino production in dense plasma. Aims. To achieve such a goal requires determining precisely its fundamental parameters. This is the goal of this paper. Methods. We present new multi-site photometric observations obtained in 2001 and …
A Multisite Photometric Campaign On The Pre-Main-Sequence Δ Scuti Pulsator Ip Persei, Vincenzo Ripepi, T D. Oswalt
A Multisite Photometric Campaign On The Pre-Main-Sequence Δ Scuti Pulsator Ip Persei, Vincenzo Ripepi, T D. Oswalt
Aerospace, Physics, and Space Science Faculty Publications
We present the results of a photometric multisite campaign on the δ Scuti Pre-Main-Sequence star IP Per. Nine telescopes have been involved in the observations, with a total of about 190 h of observations over 38 nights. Present data confirms the multiperiodic nature of this star and leads to the identification of at least nine pulsational frequencies. Comparison with the predictions of linear non-adiabatic radial pulsation models allowed us to identify only five of the nine observed frequencies, and to constrain the position of IP Per in the HR diagram. The latter is in good agreement with the empirical determination …
Multisite Observations Of The Pms Δ Scuti Star V351 Ori, Vincenzo Ripepi, T D. Oswalt, Mark J. Rudkin, Kyle B. Johnston
Multisite Observations Of The Pms Δ Scuti Star V351 Ori, Vincenzo Ripepi, T D. Oswalt, Mark J. Rudkin, Kyle B. Johnston
Aerospace, Physics, and Space Science Faculty Publications
We present the results of multisite observations spanning two years on the pre-main-sequence (PMS) star V351 Ori. A total of around 180 hours of observations over 29 nights have been collected, allowing us to measure five different periodicities, most likely related to the δ Scuti variability of V351 Ori. Comparison with the predictions of linear nonadiabatic radial pulsation models put stringent constraints on the stellar parameters and indicate that the distance to V351 Ori is intermediate between the lower limit measured by Hipparcos (210 pc) and that of the Orion Nebula (450 pc). However, radial pulsation models are unable to …
Wide Binary Systems And The Nature Of High-Velocity White Dwarfs, Nicole M. Silvestri, Terry D. Oswalt, Suzanne L. Hawley
Wide Binary Systems And The Nature Of High-Velocity White Dwarfs, Nicole M. Silvestri, Terry D. Oswalt, Suzanne L. Hawley
Aerospace, Physics, and Space Science Faculty Publications
We present measured radial velocities and complete space motions for 116 white dwarf stars with M dwarf companions. Thirteen pairs have " halo-like " velocities. According to a recent study by Oppenheimer et al., all these high-velocity white dwarfs should be considered part of the dark matter heavy halo of the Galaxy, based on their kinematics. Based on the near-solar abundance levels of the M dwarf companions, we conclude that 12 of our 13 high-velocity white dwarfs are actually part of the high-velocity tail of the thick disk, rather than the dark matter halo of the Galaxy, in agreement with …
Asteroseismology Of Rxj 2117+3412, The Hottest Pulsating Pg 1159 Star, G Vauclair, Matt A. Wood
Asteroseismology Of Rxj 2117+3412, The Hottest Pulsating Pg 1159 Star, G Vauclair, Matt A. Wood
Aerospace, Physics, and Space Science Faculty Publications
The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified ℓ = 1 modes among the 48 independent pulsation frequencies detected in the power spectrum, leads to the derivation of the rotational splitting, the period spacing and the mode trapping cycle and amplitude, from which a number of fundamental parameters can be deduced. The average rotation period is 1.16 ± 0.05 days. The trend for the rotational splitting to decrease with increasing periods is incompatible with a …
White Dwarfs In Common Proper Motion Binary Systems: Mass Distribution And Kinematics, Nicole M. Silvestri, Terry D. Oswalt, Matt A. Wood, Jonathan Allyn Smith, Iain Neill Reid, Edward M. Sión
White Dwarfs In Common Proper Motion Binary Systems: Mass Distribution And Kinematics, Nicole M. Silvestri, Terry D. Oswalt, Matt A. Wood, Jonathan Allyn Smith, Iain Neill Reid, Edward M. Sión
Aerospace, Physics, and Space Science Faculty Publications
We present the mass distribution, gravitational redshifts, radial velocities, and space motions of white dwarf stars in common proper motion binary systems. The mass distribution we derive for the 41 DA white dwarfs in this study has a mean of 0.68 ± 0.04 M⊙. This distribution has a slightly higher mean and larger dispersion than most previous white dwarf studies. We hypothesize that this is due to a higher fraction of cool (average Teff ~ 10,000 K), hence old, white dwarfs in our sample. Our results indicate that samples made up of predominantly cool, old white dwarf stars tend to …