V1400 Centauri

Lore & Background

V1400 Centauri was catalogued as early as the 1990s by the Hubble Guide Star Catalog, which measured its position from photographic plates taken in 1974 and 1979. It has also been catalogued by surveys including ASAS, 2MASS, 1SWASP, and WISE. The star was given the official variable star designation V1400 Centauri in 2015 when added to the General Catalogue of Variable Stars. A 2018 research paper nicknamed it 'Mamajek's Object' after astronomer Eric Mamajek, who identified the star's unusual dimming in 2007. The star is a member of the Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association, a group of young, comoving stars. It is a pre-main-sequence star of spectral class K5 IVe Li, indicating it is an orange K-type subgiant with weak hydrogen-alpha emission and high lithium abundance. V1400 Centauri rotates rapidly with a period of about 3.2 days, leading to starspot variability and classification as a weak-lined T Tauri variable. It is cooler and less luminous than the Sun, with an effective temperature of about 4,300 K and a luminosity about 34% that of the Sun.

Reader's Guide

The significance of V1400 Centauri lies in its 2007 dimming events, which were discovered on 3 December 2010 by Mark Pecaut, a graduate student of Eric E. Mamajek. The complex, nearly symmetrical pattern of dimming over 56 days suggested an opaque, disk-like structure eclipsing the star, attributed to an object called J1407b. Initially hypothesized to be a ringed exoplanet, this explanation became unlikely because no new eclipses were observed and historical plates showed no evidence of eclipses in the last century. Alternative proposals suggest J1407b might be a free-floating substellar object with a circumstellar disk that coincidentally eclipsed V1400 Centauri, with follow-up observations indicating its disk is not thick and dusty. The star's legacy includes its role in studying unusual dimming events and the nature of circumstellar or circumsecondary disks.

Did You Know?

• V1400 Centauri is about 7% larger than the Sun in radius but slightly less massive.
• The star's rotation period varies by 0.02 days over a 5.4-year magnetic activity cycle.
• The 2007 dimming events lasted 56 days and were discovered by Mark Pecaut in 2010.
• V1400 Centauri is classified as a weak-lined T Tauri variable due to its young age and starspot variability.