THE RØMER DELAY AND MASS RATIO OF THE sdB+dM BINARY 2M 1938+4603 FROM<i>KEPLER</i>ECLIPSE TIMINGS

Barlow, B. N.; Wade, Richard A.; Liss, S.

doi:10.1088/0004-637x/753/2/101

Cited by 55 publications

(36 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This analysis makes use of the eclipse depth and shape, including corrections for gravitational lensing, and is consistent with the Rømer delay measured independently from eclipse times, Δt = 4.2 ± 0.6 s. This would be the first detection of an observed Rømer delay for ground-based eclipse measurements (cf. Bloemen et al 2012;Barlow et al 2012), although in all of these systems there is the possibility that the time delay is instead related to a finite, but small, eccentricity.…”

Section: Discussionmentioning

confidence: 99%

Properties of an Eclipsing Double White Dwarf Binary NLTT 11748

Kaplan

Marsh

Walker

et al. 2013

ApJ

View full text Add to dashboard Cite

We present high-quality ULTRACAM photometry of the eclipsing detached double white dwarf binary NLTT 11748. This system consists of a carbon/oxygen white dwarf and an extremely low mass (<0.2 M ) helium-core white dwarf in a 5.6 hr orbit. To date, such extremely low-mass white dwarfs, which can have thin, stably burning outer layers, have been modeled via poorly constrained atmosphere and cooling calculations where uncertainties in the detailed structure can strongly influence the eventual fates of these systems when mass transfer begins. With precise (individual precision ≈1%), high-cadence (≈2 s), multicolor photometry of multiple primary and secondary eclipses spanning >1.5 yr, we constrain the masses and radii of both objects in the NLTT 11748 system to a statistical uncertainty of a few percent. However, we find that overall uncertainty in the thickness of the envelope of the secondary carbon/oxygen white dwarf leads to a larger (≈13%) systematic uncertainty in the primary He WD's mass. Over the full range of possible envelope thicknesses, we find that our primary mass (0.136-0.162 M ) and surface gravity (log(g) = 6.32-6.38; radii are 0.0423-0.0433 R ) constraints do not agree with previous spectroscopic determinations. We use precise eclipse timing to detect the Rømer delay at 7σ significance, providing an additional weak constraint on the masses and limiting the eccentricity to e cos ω = (−4 ± 5) × 10 −5 . Finally, we use multicolor data to constrain the secondary's effective temperature (7600±120 K) and cooling age (1.6-1.7 Gyr).

show abstract

Section: Discussionmentioning

confidence: 99%

Properties of an Eclipsing Double White Dwarf Binary NLTT 11748

Kaplan

Marsh

Walker

et al. 2013

ApJ

View full text Add to dashboard Cite

show abstract

“…This discrepancy can result from the time difference between the primary and secondary eclipses due to LTT in a binary with unequal masses (Barlow et al 2012;Parsons et al 2014). The Rømer delay is given by Kaplan (2010), as follows:…”

Section: Eclipse Timing Variation and Its Implicationmentioning

confidence: 99%

KIC 11401845: An Eclipsing Binary with Multiperiodic Pulsations and Light-travel Time

Lee

Hong

Koo

2017

ApJ

View full text Add to dashboard Cite

We report the Kepler photometry of KIC 11401845 displaying multiperiodic pulsations, superimposed on binary effects. Light-curve synthesis represents that the binary star is a short-period detached system with a very low mass ratio of q = 0.070 and filling factors of F 1 = 45 % and F 2 = 99 %. Multiple frequency analyses were applied to the light residuals after subtracting the synthetic eclipsing curve from the observed data. We detected 23 frequencies with signal to noise amplitude ratios larger than 4.0, of which the orbital harmonics (f 4 , f 6 , f 9 , f 15 ) in the low frequency domain may originate from tidally excited modes. For the high frequencies of 13.7−23.8 day −1 , the period ratios and pulsation constants are in the ranges of P pul /P orb = 0.020−0.034 and Q = 0.018−0.031 d, respectively. These values and the position on the Hertzsprung-Russell diagram demonstrate that the primary component is a δ Sct pulsating star. We examined the eclipse timing variation of KIC 11401845 from the pulsation-subtracted data and found a delay of 56±17 s in the arrival times of the secondary eclipses relative to the primary eclipses. A possible explanation of the time shift may be some combination of a light-travel-time delay of about 34 s and a very small eccentricity of e cos ω < 0.0002. This result represents the first measurement of the Rømer delay in non-compact binaries.

show abstract

“…An extension of this test to a g-mode pulsator in a close eclipsing binary may become possible with the sdB+dM system 2M 1938+4603 recently discovered by the Kepler space mission (Østensen et al 2010). Barlow et al (2012) proposed an orbital solution from Kepler eclipse timings, assuming a perfectly circular orbit. The mass ratio and therefore the masses of the two components are, however, very sensitive to the eccentricity.…”

Section: Comparison Between Various Estimationsmentioning

confidence: 99%

Third generation stellar models for asteroseismology of hot B subdwarf stars

Grootel

Charpinet

Brassard

et al. 2013

A&A

View full text Add to dashboard Cite

Context. Asteroseismic determinations of structural parameters of hot B subdwarfs (sdB) have been carried out for more than a decade now. These analyses rely on stellar models whose reliability for the required task needs to be evaluated critically. Aims. We present new models of the so-called third generation (3G) dedicated to the asteroseismology of sdB stars, in particular to long-period pulsators observed from space. These parameterized models are complete static structures suitable for analyzing both p-and g-mode pulsators, contrary to the former second generation (2G) models that were limited to p-modes. While the reliability of the 2G models has been successfully verified in the past, this important test still has to be conducted on the 3G structures. Methods. The close eclipsing binary PG 1336−018 provides a unique opportunity to test the reliability of hot B subdwarf models. We compared the structural parameters of the sdB component in PG 1336−018 obtained from asteroseismology based on the 3G models, with those derived independently from the modeling of the reflection/irradiation effect and the eclipses observed in the light curve. Results. The stellar parameters inferred from asteroseismology using the 3G models are found to be remarkably consistent with both the preferred orbital solution obtained from the binary light curve modeling and the updated spectroscopic estimates for the surface gravity of the star. The seismology gives M * = 0.471 ± 0.006 M , R * = 0.1474 ± 0.0009 R , and log g = 5.775 ± 0.007, while orbital modeling leads to M * = 0.466 ± 0.006 M , R * = 0.15 ± 0.01 R , log g = 5.77 ± 0.06, and spectroscopy yields log g = 5.771 ± 0.015. In comparison, seismology from a former analysis based on the 2G models gave very similar results with M * = 0.459 ± 0.005 M , R * = 0.151 ± 0.001 R , and log g = 5.739 ± 0.002. We also show that the uncertainties on the input physics included in stellar models have, at the current level of accuracy, no noticeable impact on the structural parameters derived by asteroseismology. Conclusions. The stellar models (both of second and third generation) presently used to carry out quantitative seismic analyses of sdB stars are reliable for the task. The stellar parameters inferred by this technique, at least for those that could be tested (M * , R, and log g), appear to be both very precise and accurate, as no significant systematic effect has been found.

show abstract

THE RØMER DELAY AND MASS RATIO OF THE sdB+dM BINARY 2M 1938+4603 FROMKEPLERECLIPSE TIMINGS

Cited by 55 publications

References 21 publications

Properties of an Eclipsing Double White Dwarf Binary NLTT 11748

Properties of an Eclipsing Double White Dwarf Binary NLTT 11748

KIC 11401845: An Eclipsing Binary with Multiperiodic Pulsations and Light-travel Time

Third generation stellar models for asteroseismology of hot B subdwarf stars

Contact Info

Product

Resources

About