English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present the discovery from TESS data of LTT 1445Ab. At a distance of 6.9parsecs, it is the second nearest transiting exoplanet system found to date,and the closest one known for which the primary is an M dwarf. The host stellarsystem consists of three mid-to-late M dwarfs in a hierarchical configuration,which are blended in one TESS pixel. We use data from MEarth and results fromthe SPOC DV report to determine that the planet transits the primary star inthe system. The planet has a radius 1.38 R_Earth, an orbital period of 5.35882days, and an equilibrium temperature of 433 K. With radial velocities fromHARPS, we place a three-sigma upper mass limit of 8.4 M_Earth on the candidate.The planet provides one of the best opportunities to date for the spectroscopicstudy of the atmosphere of a terrestrial world. The presence of stellarcompanions of similar spectral type may facilitate such ground-based studies byproviding a calibration source to remove telluric variations. In addition, wepresent a detailed characterization of the host stellar system. We usehigh-resolution spectroscopy and imaging to rule out the presence of any otherclose stellar or brown dwarf companions. Nineteen years of photometricmonitoring of A and BC indicates a moderate amount of variability, in agreementwith the observed low-level, short-term variability in the TESS light curvedata. We derive a preliminary astrometric orbit for the BC pair that reveals anedge-on and eccentric configuration. The presence of a transiting planet inthis system raises the possibility that the entire system is co-planar, whichimplies that the system may have formed from the early fragmentation of anindividual protostellar core.

Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M Dwarf System at 6.9 Parsecs