TW Hydrae

TW Hydrae (TW Hya) is the nearest T-Tauri star to the Sun, and is the star for which TW Hydrae association is named. It has a face-on protoplanetary disk that includes a gap. Such a gap suggests a likely extra-solar planet, which would be TW Hydrae b, with a mass of up to about 1.5 Neptune masses, i.e., roughly 25 Earth masses. (A discounted study had theorized a more massive planet based on other arguments.) Characteristics:

• Hydra - constellation.
• 11h01m51.9054s - right ascension.
• -34deg42m17.0316s - declination.
• +11.27 - apparent magnitude.
• 196 ly - distance.
• K­6 - spectral type.
• 0.8 - M_Sun.
• +0.67 - B-V color index.