Future Direct Spectroscopic Detection of Hot Jupiters with IGRINS

TL;DR

This paper explores using the IGRINS near-infrared spectrograph to detect spectral signatures of Hot Jupiters, enabling direct measurement of their true masses beyond traditional radial velocity methods.

Contribution

It proposes a novel observational technique combining spectral cross-correlation with IGRINS to directly detect planetary signals and determine actual planet masses.

Findings

IGRINS can detect spectral signatures of Hot Jupiters.

The method allows for precise determination of true planet masses.

Simulations show potential for near-future observations.

Abstract

With about 700 confirmed extrasolar planets, it is time to move beyond discovery and towards characterization. Perhaps the most basic parameter of an extrasolar planet is its mass; however, this is very difficult to determine if the planet does not transit the star. The radial velocity technique, still the most fruitful method of discovering planets in the solar neighborhood, can only determine a minimum planet mass. We investigate a method using the near-future IGRINS near infrared spectrograph to detect the orbital motion of the planet itself. We simulate several observations of a star with an orbiting planet, and search for the spectral signature of the planet by cross-correlating against planet model spectra. A detection appears as a strong peak in the cross-correlation function, and gives the radial velocity of the planet at the time of observation. This, combined with the motion of the star from traditional radial velocity planet search programs, can determine the actual planet mass. We find that the IGRINS instrument can detect the spectral signature from large planets on very close orbits (so-called Hot Jupiters), and that the detections can provide tight constraints on the true planet mass.