Multi-epoch precise photometry from the ground: MUDEHaR, magnetic O stars and everything around

Holgado, Gonzalo; Maíz Apellániz, Jesús; Caballero, Jose A.; Alfaro Navarro, Emilio J.; Bowman, Dominic M.
Bibliographical reference

EAS2024

Advertised on:
7
2024
Number of authors
5
IAC number of authors
1
Citations
0
Refereed citations
0
Description
MUDEHaR has completed its first of five years of project, and all the information is already available for exploitation. MUDEHaR is a multi-epoch photometric survey with two narrow filters in Hα and the calcium triplet window that uses T80Cam at the JAST80 telescope at Javalambre spanish astronomical observatory. It is obtaining ~50 epochs/year per field for 20 fields in the Galactic disk, each of two square degrees, for a total of 40 square degrees. Focused on stellar clusters and HII regions including bright stars, it's main objective is to detect tens of thousands OB stars that present emission/variability in Hα on a days-months-years scale, including massive stars with a magnetic field, pulsating stars, and other types of variable stars. But the reduction process produces results for all tens of thousands of stars present in each field. Observations from the first MUDEHaR year will soon be available on the web. Here I present some of its singular characteristics such as its extensive dynamic range in magnitudes towards the brightest stars (AB mag 3-17 with S/N> 100); and a powerful resolution capability in the sky (0.55 arcsec/pix). I will also present how to access to the data and some useful tools for the treatment of MUDEHaR data. I will present the calibration and precision results from this first year of observations by comparing them with eclipsing stars and Cepheids that also have multi-epoch information from Gaia. The comparison is highly favorable, with very competitive uncertainties, and even improving the period determination for some binary systems. Finally, I will delve into the potential of MUDEHaR to identify potential magnetic candidates among massive stars by means of photometric variability. Only 10%-20% of OB stars present magnetic field, and the origin is still in debate. In this context, I outline here the multi-step process involved in identifying OB magnetic stars, detailing my involvement in various stages and highlighting the significance of MUDEHaR observations in this process.