The CubeSpec space mission

Abstract

Context. There is currently a niche for providing high-cadence, high resolution, time-series optical spectroscopy from space, which can be filled by using a low-cost cubesat mission. The Belgian-led ESA/KU Leuven CubeSpec mission is specifically designed to provide space-based, low-cost spectroscopy with specific capabilities that can be optimised for a particular science need. Approved as an ESA in-orbit demonstrator, the CubeSpec satellite’s primary science objective will be to focus on obtaining high-cadence, high resolution optical spectroscopic data to facilitate asteroseismology of pulsating massive stars. Aims. In this first paper, we aim to search for pulsating massive stars suitable for the CubeSpec mission, specifically β Cep stars, which typically require time-series spectroscopy to identify the geometry of their pulsation modes. Methods. Based on the science requirements needed to enable asteroseismology of massive stars with the capabilities of CubeSpec’s spectrograph, we combined a literature study for pulsation with the analysis of recent high-cadence time-series photometry from the Transiting Exoplanet Survey Satellite (TESS) mission to classify the variability for stars brighter than V ≤ 4 mag and between O9 and B3 in spectral type. Results. Among the 90 stars that meet our magnitude and spectral type requirements, we identified 23 promising β Cep stars with high-amplitude (non-)radial pulsation modes with frequencies below 7 d−1. Using further constraints on projected rotational velocities, pulsation amplitudes, and the number of pulsation modes, we devised a prioritised target list for the CubeSpec mission according to its science requirements and the potential of the targets for asteroseismology. The full target catalogue further provides a modern TESS-based review of line profile and photometric variability properties among bright O9–B3 stars.

Pulsating B stars in the Scorpius-Centaurus Association with TESS

“…10) clearly shows low-amplitude pulsations, making it the second-brightest 𝛽 Cep star in the sky (after 𝛽 Cen). The 𝛽 Cep variability of 𝛼 Cru from the TESS data was also noted in Table A.1 of Bowman et al (2022), although no frequencies were given. The amplitude spectrum in Fig.…”

Introduction to gravitational redshift of quantum photons propagating in curved spacetime

“…It is also of great interest to actively attempt to measure the effects of gravitational redshift for purposes of foundational experiments or sensing. A promising avenue to implement the tests discussed above is the use of Cubesats and other similar crafts [168,169,170] that are now being considered for use in space-based classical [171,172,173] and quantum experiments [174,175,176]. In this case, small and relatively inexpensive satellites can be deployed at a fraction of the cost of conventional missions, where the craft itself can be potentially loaded with all necessary equipment to perform (reasonable) long-range experiments.…”

Convective Boundary Mixing in Main-Sequence Stars: Theory and Empirical Constraints

“…While the oscillations of this star have previously been studied using both photometry and spectroscopy [219][220][221][222][223][224], no detailed asteroseismic modeling has so far been achieved. Given that the primary β Cep star has been selected as a priority 1A target for the future asteroseismic CubeSpec space mission [225] this might change in the future.…”