Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994aas...185.4817f&link_type=abstract
American Astronomical Society, 185th AAS Meeting, #48.17; Bulletin of the American Astronomical Society, Vol. 26, p.1390
Astronomy and Astrophysics
Astronomy
Scientific paper
We present intermediate-resolution (lambda /Delta lambda ~ 50) infrared (2--14 microns) spectroscopy of four early-type main-sequence stars, conducted with the Aerospace Corp. Infrared Spectrograph. We observed beta UMa (A1 V), alpha Aql (A7 V), and beta Leo (A3 V) at the 1.3-m KPNO telescope in May 1993, and zeta Lep (A2 V) at the 3.0-m IRTF telescope in Nov. 1993. The Vega-type stars beta UMa and zeta Lep showed weak but definite excess flux at ~ 10 microns in previous groundbased photometric surveys (Fajardo-Acosta, Telesco & Knacke 1994, in preparation; Aumann & Probst 1991, ApJ, 368, 264). We observed alpha Aql and beta Leo to confirm that their ~ 10 microns spectra do not show any excess. The weak ~ 10 microns excess features in our spectra of beta UMa and zeta Lep are probably indicative of large grains and/or a small quantity of dust around these stars. Their weak features contrast with the prominent silicate emission feature previously seen in beta Pic and 51 Oph. The grains are hotter in zeta Lep than in beta UMa, as indicated by an excess already present at short wavelengths ( ~ 8.5 microns) in the spectrum of the former, as opposed to the 10--11 microns excess of the latter. Dust around these two stars could be an assemblage of amorphous minerals, probably of a variety of sizes, as suggested by their broad features. We compared the excess spectra of zeta Lep and beta UMa with those of comets (reviewed by Hanner, Lynch, & Russell 1994, ApJ, 425, 274) and found they resemble those of dust-poor comets such as Austin 1990 V and Okazaki-Levy-Rudenko 1989 XIX.
Fajardo-Acosta Sergio Bernabe
Hackwell John A.
Hanner Martha S.
Knacke Roger F.
Lynch David K.
No associations
LandOfFree
2--14 microns Spectroscopy of Vega-type Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with 2--14 microns Spectroscopy of Vega-type Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 2--14 microns Spectroscopy of Vega-type Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1320974