Recent theoretical work has shown that the pre-main-sequence (PMS) evolution of stars is much more complex than previously envisioned. Instead of the traditional steady, one-dimensional solution, accretion may be episodic and not necessarily symmetrical, thereby affecting the energy deposited inside the star and its interior structure. Given this new framework, we want to understand what controls the evolution of accreting stars. We use the MESA stellar evolution code with various sets of conditions. In particular, we account for the (unknown) efficiency of accretion in burying gravitational energy into the protostar through a parameter, $ξ$, and we vary the amount of deuterium present. We confirm the findings of previous works that the evolution changes significantly with the amount of energy that is lost during accretion. We find that deuterium burning also regulates the PMS evolution. In the low-entropy accretion scenario, the evolutionary tracks in the H-R diagram are significantly different from the classical tracks and are sensitive to the deuterium content. A comparison of theoretical evolutionary tracks and observations allows us to exclude some cold accretion models ($ξ\sim 0$) with low deuterium abundances. We confirm that the luminosity spread seen in clusters can be explained by models with a somewhat inefficient injection of accretion heat. The resulting evolutionary tracks then become sensitive to the accretion heat efficiency, initial core entropy, and deuterium content. In this context, we predict that clusters with a higher D/H ratio should have less scatter in luminosity than clusters with a smaller D/H. Future work on this issue should include radiation-hydrodynamic simulations to determine the efficiency of accretion heating and further observations to investigate the deuterium content in star-forming regions. (abbrev.)
PENELLOPE VII: Revisiting empirical relations to measure accretion luminosity
INAF-Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；European Southern Observatory（欧洲南方天文台）；Boston University（波士顿大学）；Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences（孔科利天文台，匈牙利研究与教育网络天文学与地球科学研究中心）；University of Vienna（维也纳大学）；SETI Institute（搜寻地外文明研究所）；Observatoire de Paris - PSL University（巴黎天文台-PSL大学）；Univ. grenoble Alpes（格勒诺布尔阿尔卑斯大学）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Università degli Studi di Milano（米兰大学）；Leiden University（莱顿大学）
Revisiting Planetary Systems in Okayama Planet Search Program: A new long-period planet, RV astrometry joint analysis, and multiplicity-metallicity trend around evolved stars
Revisiting the Evolutionary Status of Massive Stars at the central parsec of the Milky Way
Astronomický ústav, Akademie věd Ceské republiky（捷克科学院天文研究所）；Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez（阿道夫·伊巴涅斯大学人文科学学院科学系）；Millennium Nucleus on Transversal Research and Technology to Explore Supermassive Black Holes (TITANS)（探索超大质量黑洞跨学科研究与技术千年核心（TITANS））；Department of Astronomy, University of Geneva（日内瓦大学天文学系）
