NOAO > Observing Info > Approved Programs > 2017A-0422
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NOAO > Observing Info > Approved Programs > 2017A-0422 |
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PI: Constantine Deliyannis, Indiana U., con@astro.indiana.edu
Address: Astronomy Department, 727 E. 3rd St., 318 Swain Hall West, Bloomington, IN 47405-7105 USA
CoI: Robin Jeffries, Keele University
CoI: Richard Jackson, Keele University
Title: The radii of M-dwarfs in the Praesepe cluster
Abstract: The radius of a star is one of the most basic outputs of a stellar model. Yet
observations of low-mass eclipsing binaries and pre-main- sequence (PMS) stars
show that standard evolutionary calculations significantly underpredict their
radii. This ``radius inflation'' is not yet fully explained – it may be due
to magnetic activity and rapid rotation, or it could be indicating some other
deficiency in low-mass evolutionary models. There is a renewed urgency in
accurately estimating the properties of low-mass M-dwarfs driven by the
discovery of, and the need to characterise, their (habitable?) exoplanetary
systems. Last semester we requested time to observe 100's of stars in the young
Pleiades cluster (age 100 Myr). We have already reduced Pleiades data taken in
two second-half nights at the end of September (2016), using our custom- written
pipeline, and have verified our expectations regarding SNR and ability to
resolve down to 10km/sec. Here, we propose to estimate the average radii of
M-dwarfs in the Praesepe cluster (age 700 Myr) and compare them with
evolutionary models and the interferometric radii of nearby, but magnetically
inactive field M-dwarfs. Our aim is to determine whether the radius inflation
seen in PMS M-dwarfs at ages less than 140 Myr, persists in older stars of
similar mass that are well-established on the main sequence, and whether any
inflation correlates with magnetic activity or rotation. Our technique models
projected radii determined from the product of WIYN measurements of rotational
broadening and K2 rotation periods, to yield average radii for groups of stars.
Large samples are required and owing to its proximity, richness and presence in
the K2 campaign 5 field, the Praesepe cluster is an ideal and very important
target for fiber spectroscopy.
Program Type: ITAC
Scheduled Nights:
Run 1 (2017A): WIYN/HYDR -- 3n on Feb 01 - Feb 02 2017, Feb 17 2017
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2017A-0422 |
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