Distribuição de Tempo 2026V - STELES Science Verification

Verificação de Ciência do STELES - Resultados da Seleção de Propostas e Alocação de Tempo
STELES Science Verification - Proposal Selection Results and Time Allocation

STELES Science Verification Program

The SOAR Telescope Echelle Spectrograph (STELES) will conduct its first Science Verification observations during the second half of 2026. The program is intended to demonstrate the instrument's scientific capabilities under real observing conditions and to provide the astronomical community with an initial assessment of its performance.

The Science Verification campaign comprises 11 nights of observing time, distributed across three observing runs in September, October, and December 2026 (more information is provided in the SV Call webpage). Observations will be conducted in queue mode by the STELES and SOAR teams, allowing targets to be selected according to their visibility and the prevailing observing conditions.

The program will focus on demonstrating the capabilities of STELES across its broad wavelength range, with particular emphasis on its high spectral resolution and near-UV sensitivity. The selected programs cover a broad range of scientific topics, providing an opportunity to assess the instrument's performance for different types of astronomical sources and observing strategies.

Call for Proposals and TAC Evaluation

The Call for Proposals for the STELES Science Verification program was opened in July 2026 and was open to the astronomical community (link). Proposals were encouraged to make use of the distinctive capabilities of STELES, particularly its high spectral resolution, broad wavelength coverage, and near-UV sensitivity.

A total of 71 proposals were received, requesting a total of 538.6 hours of observing time. Following the evaluation, 23 programs were selected for execution, corresponding to approximately 32% of the submitted proposals. The total amount of time requested resulted in an oversubscription of 5.4 relative to the available Science Verification time (approximately 100 hours).

The proposals were evaluated by the STELES Science Verification Time Allocation Committee (TAC), which considered the scientific merit of each program, its suitability for the capabilities of STELES, the feasibility of the proposed observations, its potential contribution to the scientific verification of the instrument and the pressure factor of each observing run to accommodate all approved projects.

The selected programs represent a broad range of scientific topics and observing strategies, providing a representative test of STELES across different types of astronomical targets and scientific applications.

Scientific Scope of the Submitted Proposals

The proposals received for the STELES Science Verification program covered a broad range of scientific topics, reflecting the versatility of the instrument and the diverse interests of the astronomical community. The submitted programs included studies of stellar abundances and stellar astrophysics, star formation and young stellar objects, Solar System objects, exoplanets, emission-line and nebular sources, and time-domain phenomena, among other topics.

The distribution of proposals and requested observing time across the main scientific areas is summarized below. Both the number of proposals and the amount of requested time are shown, as these provide complementary measures of the scientific demand for STELES.

Selected Programs and Time Allocation

Following the TAC evaluation, 23 programs were selected for the STELES Science Verification campaign. The approved times ranged between 0.64 to 9.60 hours per project. The selected projects span a broad range of scientific topics and collectively make use of the main capabilities of STELES, including high spectral resolution, broad wavelength coverage, and near-UV spectroscopy.

The table below lists the approved programs.

Institutional Participation

The STELES Science Verification call attracted proposals from a broad range of institutions, reflecting the interest in the new instrument across the astronomical community. The 23 programs selected for execution involve researchers from 18 institutions, including institutions in South America, North America and Europe.

The distribution of the selected programs by the Principal Investigator's home institution and TAC partner is summarized below, showing both the number of approved programs and the corresponding awarded observing time.

Next steps

The strong response to the call demonstrates the broad scientific interest in STELES and its capabilities and the selected programs will provide an important first assessment of the instrument's performance for science observations. 

The selected programs will be executed during the three STELES Science Verification observing runs scheduled for September 8–11, October 7–10, and December 4–6, 2026. The final scheduling of individual targets will be performed in queue mode, taking into account target visibility, observing conditions, and the operational requirements of the Science Verification campaign.

Data obtained through the Science Verification program will be processed by the STELES/SOAR team and made available to the respective Principal Investigators following the observations. Data products are expected to be delivered within approximately 1-3 weeks after each observing run, with a three-month proprietary period.