Isochronal age-mass discrepancy of young stars: SCExAO/CHARIS integral field spectroscopy of the HIP 79124 triple system

Journal
Date Issued
2019
Author(s)
Asensio-Torres, Ruben
•
Currie, Thayne
•
Janson, Markus
•
•
Kuzuhara, Masayuki
•
Hodapp, Klaus
•
Brandt, Timothy D.
•
Guyon, Olivier
•
Lozi, Julien
•
Groff, Tyler
•
Kasdin, Jeremy
•
Chilcote, Jeffrey
•
Jovanovic, Nemanja
•
Martinache, Frantz
•
Sitko, Michael
•
Serabyn, Eugene
•
Wagner, Kevin
•
Akiyama, Eiji
•
Kwon, Jungmi
•
Uyama, Taichi
•
Yang, Yi
•
Nakagawa, Takao
•
Hayashi, Masahiko
•
McElwain, Michael
•
Kudo, Tomoyuki
•
Henning, Thomas
•
Tamura, Motohide
DOI
Abstract
We present SCExAO/CHARIS 1.1-2.4 μm integral field direct spectroscopy of the young HIP 79124 triple system. HIP 79124 is a member of the Scorpius-Centaurus association, consisting of an A0V primary with two low-mass companions at a projected separation of < 1″. Thanks to the high quality wavefront corrections provided by SCExAO, both companions are decisively detected without the employment of any PSF-subtraction algorithm to eliminate quasi-static noise. The spectrum of the outer C object is very well matched by Upper Scorpius M4 ± 0.5 standard spectra, with a Teff = 2945 ± 100 K and a mass of ∼350 MJup. HIP 79124 B is detected at a separation of only 180 mas in a highly-correlated noise regime, and it falls in the spectral range M6 ± 0.5 with Teff = 2840 ± 190 K and ∼100 MJup. Previous studies of stellar populations in Sco-Cen have highlighted a discrepancy in isochronal ages between the lower-mass and higher-mass populations. This could be explained either by an age spread in the region, or by conventional isochronal models failing to reproduce the evolution of low-mass stars. The HIP 79124 system should be coeval, and therefore it provides an ideal laboratory to test these scenarios. We place the three components in a color-magnitude diagram and find that the models predict a younger age for the two low-mass companions (∼3 Myr) than for the primary star (∼6 Myr). These results imply that the omission of magnetic effects in conventional isochronal models inhibit them from reproducing early low-mass stellar evolution, which is further supported by the fact that new models that include such effects provide more consistent ages in the HIP 79124 system.
Volume
622
Start page
A42
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2019A&A...622A..42A
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

AsensioTorres_2019_AA_622_A42.pdf

Description
pdf editoriale
Size

819.15 KB

Format

Adobe PDF

Checksum (MD5)

65e9553628a1c1db9508a418f0f9f769