CHXR 73 A and B – Red Dwarf and Substellar Companion

This NASA Hubble Space Telescope image shows one of the smallest objects ever seen around a normal star. Astronomers believe the object is a brown dwarf because it is 12 times more massive than Jupiter. The brown dwarf candidate, called CHXR 73 B, is the bright spot at lower right. It orbits a red dwarf star, dubbed CHXR 73, which is a third less massive than the Sun. At 2 million years old, the star is very young when compared with our middle-aged 4.6-billion-year-old Sun.

CHXR 73 B orbits 19.5 billion miles from its star, or roughly 200 times farther than Earth is from the Sun.

The star looks significantly larger than CHXR 73 B because it is much brighter than its companion. CHXR 73 B is 1/100 as bright as its star. The cross-shaped diffraction spikes around the star are artifacts produced within the telescope's optics. The star is 500 light-years away from Earth.

Hubble's Advanced Camera for Surveys snapped the image in near-infrared light on Feb. 10 and 15, 2005. The color used in the image does not reflect the object's true color.

Members of the research team are K. L. Luhman, Penn State University; J. C. Wilson, M. F. Skrutskie, M. J. Nelson, and D. E. Peterson, University of Virginia; W. Brandner, Max-Planck Institute for Astronomy; and J. D. Smith, M. C. Cushing, and E. Young, University of Arizona.

About the colours

This image was made using data from a single filter in the near-infrared part of the spectrum so it is in fact monochrome or black and white. The color results from mapping each brightness step in the grayscale image to a separate color, known as a color-mapped or color-indexed image. In this case the color scale is a ramp from black through red and orange to white.

About the data

This image was created from HST data from proposal 10138 : K. Luhman (Pennsylvania State University) and G. Fazio (Harvard-Smithsonian Center for Astrophysics).

The science team includes: K. Luhman (Pennsylvania State University), J. Wilson (University of Virginia), W. Brandner (Max Planck Institute for Astronomy, Heidelberg, Germany), M. Skrutskie and M. Nelson (University of Virginia), J. Smith (Steward Observatory, University of Arizona), D.Peterson (University of Virginia), and M. Cushing and E. Young (Steward Observatory, University of Arizona).