Calendar

May
29
Fri
Remote Colloquium Thesis Defense: Drew Chojnowski
May 29 @ 2:30 pm – 3:30 pm
Remote Colloquium Thesis Defense: Drew Chojnowski @ Online

H-Band Spectroscopy of Exotic, Massive Stars

Drew Chojnowski, NMSU

We report on spectroscopy of exotic B-type emission line (Be) stars and chemically peculiar (CP) stars in the near-infrared (NIR) H-band, using data provided by the Apache Point Observatory Galactic Evolution Experiment, one of the sub-surveys of the Sloan Digital Sky Survey (SDSS). Between 2011-2020, SDSS/APOGEE has observed more than a million stars in the Milky Way Galaxy (MW), with roughly 10% of the targets being hot, blue stars that serve as telluric absorption standard stars (TSS). The TSS are selected mostly on the basis of having blue raw J-K color indices with no preference for any particular spectral type that might be known from optical spectroscopy. This targeting strategy has led to the TSS being a mixed bag, with those observed in the MW Halo typically being F-type stars that are only slightly more massive than the Sun, and with those observed in the MW Disk and Bulge being OBA-type stars of a few up to 20 times the mass of the Sun. While the vast majority of the TSS are superficially normal main sequence stars, the inclusion of large numbers of Be and CP stars has serendipitously resulted in the largest ever homogeneous spectroscopic surveys of these stellar classes, both of which present observational anomalies that remain very poorly understand despite more than a hundred years of research. Prior to SDSS/APOGEE, the H-band spectra of Be and CP stars had only been discussed in a handful of studies, all of which used small numbers of spectra of considerably lower resolution than the R=22,500 of the APOGEE instruments. The material presented in this thesis therefore represents the first ever detailed studies of Be and CP stars in the H-band, while also greatly expanding the known samples through discovery of many hundreds of new examples.

Jun
12
Fri
Thesis Proposal: Kristen Luchsinger
Jun 12 @ 3:00 pm – 4:00 pm
Thesis Proposal: Kristen Luchsinger @ Remote via Zoom

Title

Kristen Luchsinger, NMSU


Aug
21
Fri
No Colloquium
Aug 21 @ 3:15 pm – 4:15 pm
No Colloquium @ BX102

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Aug
28
Fri
Colloquium: OPEN (Host: TBD)
Aug 28 @ 3:15 pm – 4:15 pm
Colloquium: OPEN (Host: TBD) @ BX102

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Sep
4
Fri
Colloquium: OPEN (Host: TBD)
Sep 4 @ 3:15 pm – 4:15 pm
Colloquium: OPEN (Host: TBD) @ BX102

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Sep
11
Fri
Colloquium: OPEN (Host: TBD)
Sep 11 @ 3:15 pm – 4:15 pm
Colloquium: OPEN (Host: TBD) @ BX102

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Sep
18
Fri
Colloquium: OPEN (Host: TBD)
Sep 18 @ 3:15 pm – 4:15 pm
Colloquium: OPEN (Host: TBD) @ BX102

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Sep
25
Fri
Colloquium: Lauren Kahre (Host: Rene Walterbos)
Sep 25 @ 3:15 pm – 4:15 pm
Colloquium: Lauren Kahre (Host: Rene Walterbos) @ BX102

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Lauren Kahre, Affiliation

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Oct
2
Fri
Colloquium: OPEN (Host: TBD)
Oct 2 @ 3:15 pm – 4:15 pm
Colloquium: OPEN (Host: TBD) @ BX102

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Oct
9
Fri
Colloquium: OPEN (Host: TBD)
Oct 9 @ 3:15 pm – 4:15 pm
Colloquium: OPEN (Host: TBD) @ BX102

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