The Ultraviolet Type Ia Supernova CubeSat (UVIa): Science Motivation & Mission Concept

Abstract

The Ultraviolet (UV) Type Ia Supernova Mission (UVIa) is a CubeSat/SmallSat concept that stands to test critical space-borne UV technology for future missions like the Habitable Worlds Observatory (HWO) while elucidating long-standing questions about the explosion mechanisms of Type Ia supernovae (SNe Ia). UVIa will observe whether any SNe Ia emit excess UV light shortly after explosion to test progenitor/explosion models and provide follow-up over many days to characterize their UV and optical flux variations over time, assembling a comprehensive multi-band UV and optical low-redshift anchor sample for upcoming high-redshift SNe Ia surveys (e.g., Euclid, Vera Rubin Observatory, Nancy Roman Space Telescope). UVIa's mission profile requires it to perform rapid and frequent visits to newly discovered SNe Ia, simultaneously observing each SNe Ia in two UV bands (FUV: 1500-1800A and NUV: 1800-2400A) and one optical band (u-band: 3000-4200A). In this study, we describe the UVIa mission concept science motivation and basic mission design. The UVIa mission concept has been submitted to the CubeSats category of the NASA ROSES Astrophysics Research & Analysis (APRA) program (\$10M cost cap) and NASA Astrophysics Pioneers program (\$20M cost cap).

Figures (9)

• Figure 1: (Left): Model rendering of the UVIa payload, integrated into a commercial off-the-shelf 12-U spacecraft bus (provided by UTIAS-SFL). Dot-dashed lines represent obscured payload components, and the dashed line represents a shared FUV/NUV component. (Right): Anticipated Effective Area for UVIa's three channels, based on simulations of the optical design and performance. Advances in UV technology and autonomous observatory control make UVIa a viable, efficient observatory to fill in missing gaps about SNe Ia origins and empirical light curves.
• Figure 2: Regions of a SN Ia SED that will be observed by the Roman telescope. Each panel corresponds to a different redshift, $z=1.3$ and $z=2.0$, left and right respectively. These redshifts represent our cutoff where the SN Ia distances will start to be affected by the missing UV calibration data (see text for further discussion). We show boxes that represent the Wide and Deep strategy surveysRose21. The spectra presented here are of SN 2011feMazzali+2014. UVIa's filter bandpasses are shown near the top of each frame: UVIa will fill this important gap in UV calibration so that Roman can reach its full potential in SN Ia cosmology.
• Figure 3: Illustration of the differences in the expected light curves with and without companion interactionKasen10. Image credit: NASA Goddard Space Flight Center. For the companion model on the top, we have adopted a 1 $M_\odot$ red giant (binary separation $2\times10^{13}$ cm). The effects of the ejecta colliding with the companion are strongest in the blue, necessitating UV observations, and the effects fade quickly requiring rapid response time. These are both features of UVIa's design.
• Figure 4: Simulated expected $u$-band -- FUV light curves of a SN Ia at multiple distances. We have adopted SN 2011fe as a template SN IaBrown1211feZhang16. UVIa's requirements will allow us to produce $u$-band and NUV light curves to use as a cosmological training set. In the FUV, we will produce high-quality light curves for an order of magnitude more SNe Ia than current samples. We will also be able to use the FUV light curves to constrain the SED in the cosmological training sample.
• Figure 5: Expected $u$-band and NUV lightcurves for a SN Ia given the science requirements of UVIa. We adopt the binary separation of $3\times10^{12}$ cm, which is similar to both SN 2017cbvHosseinzadeh17 and SN 2019yvqBurke21, added to the light curve of SN 2011feBrown1211feZhang16. This binary separation corresponds to a $\sim 7 M_\odot$ main sequence companionKasen10. Given UVIa's sensitivity and response requirements, we will be able to detect the presence a UV excess like that of SN 2017cbv.