![Sky-coverage of the four surveys utilized in this study, with celestial coordinates displayed. It depicts three consecutive observation sectors of TESS, labeled as i−1, i, and i+1. Each of the four TESS cameras is represented by a different color. The beginning of each sector is marked in gray at an ecliptic latitude of 6 deg. The green area indicates the observing region of the fourth camera, which begins at an ecliptic latitude of 78 deg and encompasses the entire ecliptic pole. The magenta, yellow, and grey areas depict the typical 15-day observation coverage of LSST, Pan-STARRS, and ATLAS-W68, respectively. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/1IOumuamua.png?fit=1200%2C672&ssl=1)
[astro-ph.EP] Interstellar Objects (ISOs) may provide direct evidence of planetesimals ejected from early-stage solar systems. Studying these objects and predicting their detection through various surveys is vital for enhancing our understanding of planetary formation.
We show how ISO size distribution (SFD), f_D~D^-q, controls expected detections in current and future surveys. We focus on TESS and the Vera Rubin Observatory LSST while analyzing Pan-STARRS and ATLAS. TESS is expected to detect ~1 ISO from shallow SFDs (q<2.5). On the other hand, LSST is likely to detect ~0.2-100 ISO yr^-1 over its lifetime.
ATLAS is likely to detect one non-cometary object for populations with q<3. We further estimate ~0-8 detections of cometary like-3I/ATLAS objects by LSST in 10 years and ~1 cometary object detected by TESS over its mission time, independent of the nucleus size distribution.
By considering both 1I/’Oumuamua and 3I/ATLAS from the same SFD, our results suggest that more asteroid-like objects are produced rather than comets during the early stages of planetary formation. Imminent detections of ISOs by LSST will help constrain the slopes of the SFDs for asteroid-like and cometary ISOs better, and, if applicable, differentiate between them.
Rodrigo Albornoz-Montenegro, César Fuentes
Comments: 8 pages, 5 figures. Submitted to A&A
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2609.25488 [astro-ph.EP] (or arXiv:2609.25488v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2609.25488
Focus to learn more
Submission history
From: Rodrigo Albornoz
[v1] Mon, 21 Sep 2026 23:37:34 UTC (466 KB)
https://arxiv.org/abs/2609.25488
Astrobiology,
