Pulsational analysis of V 588 Mon and V 589 Mon observed with the MOST and CoRoT satellites

Abstract

The two pulsating pre-main sequence (PMS) stars V 588 Mon and V 589 Mon were observed by CoRoT for 23.4 days in March 2008 during the Short Run SRa01 and in 2004 and 2006 by MOST for a total of ~70 days. We present their photometric variability up to 1000 $\mu$ Hz and down to residual amplitude noise levels of 23 and 10 ppm of the CoRoT data for V 588 Mon and V 589 Mon, respectively. The CoRoT imagette data as well as the two MOST data sets allowed for detailed frequency analyses using Period04 and SigSpec. We confirm all previously identified frequencies, improve the known pulsation spectra to a total of 21 frequencies for V 588 Mon and 37 for V 589 Mon and compare them to our PMS model predictions. No model oscillation spectrum with l = 0, 1, 2, and 3 p-modes matches all the observed frequencies. When rotation is included we find that the rotationally split modes of the slower rotating star, V 589 Mon, are addressable via perturbative methods while for the more rapidly rotating star, V 588 Mon, they are not and, consequently, will require more sophisticated modeling. The high precision of the CoRoT data allowed us to investigate the large density of frequencies found in the region from 0 to 300 $\mu$Hz. The presence of granulation appears to be a more attractive explanation than the excitation of high-degree modes. Granulation was modeled with a superposition of white noise, a sum of Lorentzian-like functions and a Gaussian. Our analysis clearly illustrates the need for a more sophisticated granulation model.

accepted by ApJ

References in corpus (8)

• YREC: The Yale Rotating Stellar Evolution Code
• A heuristic derivation of the uncertainty of the frequency determination in time series data
• Intrinsic photometric characterisation of stellar oscillations and granulation. Solar reference values and CoRoT response functions
• Evidence for granulation in early A-type stars
• Comparing the observational instability regions for pulsating pre-main sequence and classical $\delta$ Scuti stars
• Discovery of the new slowly pulsating B star HD 163830 (B5II/III) from MOST spacebased photometry
• Reduction of time-resolved space-based CCD photometry developed for MOST Fabry Imaging data
• Rotational Splitting of Pulsational Modes

Cited by in corpus (16)

• CSI 2264: Simultaneous optical and infrared light curves of young disk-bearing stars in NGC 2264 with CoRoT and Spitzer-- evidence for multiple origins of variability
• Rotation in NGC 2264: a study based on CoRoT photometric observations
• Echography of young stars reveals their evolution
• CoRoT 223992193: A new, low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk
• Evidence of chaotic modes in the analysis of four delta Scuti stars
• A comprehensive study of young B stars in NGC 2264: I. Space photometry and asteroseismology
• Regular frequency patterns in the young delta Scuti star HD 261711 observed by the CoRoT and MOST satellites
• Mon-735: A new low-mass pre-main sequence eclipsing binary in NGC 2264
• A multiwavelength view of star-disk interaction in NGC 2264
• Impact of gaps in the asteroseismic characterization of pulsating stars. I. On the efficiency of pre-whitening
• Application of the Baade-Wesselink method to a pulsating cluster Herbig Ae star: H254 in IC348
• Searching for $\delta$ Scuti-type pulsation and characterising northern pre-main-sequence field stars
• Determining the evolutionary stage of the delta Scuti star HIP 80088 with asteroseismology
• Asteroseismology of the pre-main-sequence $\delta$ Scuti pulsator IP Persei
• Onboard Dynamic Image Exposure Control for the Star-Planet Activity Research CubeSat (SPARCS)
• Tracing early stellar evolution with asteroseismology: pre-main sequence stars in NGC 2264