Astrometry and infrared observations of the Mira variable stars AP Lyncis, V837 Herculis, and BX Camelopardalis: Implications for the period–luminosity relation of the Milky Way

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
James O Chibueze ◽  
Riku Urago ◽  
Toshihiro Omodaka ◽  
Yuto Morikawa ◽  
Masayuki Y Fujimoto ◽  
...  
Keyword(s):  
Milky Way ◽  
Large Magellanic Cloud ◽  
Variable Stars ◽  
Log P ◽  
Infrared Observations ◽  
Long Period ◽  
Mira Variable ◽  
Circumstellar Extinction ◽  
Type Variable ◽  
K Band

Abstract AP Lyn and V837 Her are long-period Mira variable stars in the Milky Way. We performed VLBI Exploration of Radio Astrometry (VERA) phase-referenced observations towards H2O masers associated with AP Lyn and V837 Her. The annual parallaxes of AP Lyn and V837 Her were obtained to be 2.008 ± 0.038 mas and 1.090 ± 0.014 mas, corresponding to distances of 498 ± 10 pc and 917 ± 12 pc, respectively. From our multi-epoch infrared observations using the Kagoshima University 1 m telescope, we derived the mean J-, H-, and K′-band magnitudes of AP Lyn, V837 Her, and an additional long-period Mira variable BX Cam, whose parallax is known. We derived their pulsation periods to be 433 ± 1 d, 520 ± 1 d, and 458 ± 1 d, respectively, using the K′-band light curves. The MK–log P relation of long-period Mira variables seem to be violated by Mira variable stars with larger-than-expected MK values (like OZ Gem) in the Milky Way because of circumstellar extinction leading to an observed dimming effect. AP Lyn, V837 Her, and BX Cam (like OZ Gem) are dimming from the trend to O-rich stars in the Large Magellanic Cloud. This implies that the high metallicity of the Milky Way galaxy increases the opacity of the Mira-type variable stars and strengthens mass loss.

Trigonometric parallax of O-rich Mira variable star OZ Gem (IRAS 07308+3037): A confirmation of the difference between the P–L relations of the Large Magellanic Cloud and the Milky Way

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Riku Urago ◽  
Ryohei Yamaguchi ◽  
Toshihiro Omodaka ◽  
Takumi Nagayama ◽  
James O Chibueze ◽  
...  
Keyword(s):  
Milky Way ◽  
Large Mass ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Mass Star ◽  
Pulsation Period ◽  
Mira Variable ◽  
Low Mass ◽  
The Difference ◽  
K Band

Abstract OZ Geminorum (OZ Gem) is a galactic Mira variable in the Milky Way (MW). We measured its annual parallax with VLBI Exploration of Radio Astrometry to be π = 0.806 ± 0.039 mas, corresponding to a distance of D = 1.24 ± 0.06 kpc. Based on multi-epoch infrared observations with the Kagoshima University 1 m telescope, we also derived the mean J-, H-, and K′-band magnitudes of OZ Gem to be 5.75 ± 0.47 mag, 4.00 ± 0.16 mag, and 2.65 ± 0.16 mag, respectively. We derived a pulsation period of OZ Gem as 592 ± 1 d from the K′-band lightcurve. From the period–luminosity (P–L) relation and two-color diagram of the Large Magellanic Cloud (LMC), the property of OZ Gem suggests that OZ Gem is assigned among the carbon-rich Mira variables. However, our optical spectroscopic observational results (with the 1.5 m Kanata telescope) confirmed OZ Gem to be an oxygen-rich Mira star with the detection of multiple titanium oxide transition absorption lines. We suggest that OZ Gem is a low-mass star evolving to an OH/IR star with large mass loss and dust formation. It is predicted that the lower limit to the initial mass of AGB stars for developing the C-rich surface chemistry is larger in the MW than in the LMC because of larger metallicity, and OZ Gem is likely to be the first example to prove this. Our results highlight the necessity of deriving the PL relation of the Milky Way with high accuracy.

scholarly journals Long-period Red Variables in the Large Magellanic Cloud from the MOA Database

2001 ◽  
Vol 183 ◽  
pp. 207-208
Author(s):  
Mine Takeuti ◽  
S. Noda ◽  
F. Abe ◽  
I. A. Bond ◽  
R. J. Dodd ◽  
...  
Keyword(s):  
Large Magellanic Cloud ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Long Period

AbstractWe studied 147 long-period red variable stars in the Large Magellanic Cloud from the MOA database. Amongst them, seven red luminous stars are likely pulsating in a higher mode.

scholarly journals A Dual CCD Mosaic Camera System Searching for Massive Compact Halo Objects (Machos)

1995 ◽  
Vol 167 ◽  
pp. 357-357
Author(s):  
Kem H. Cook
Keyword(s):  
Focal Plane ◽  
Preliminary Analysis ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Camera System ◽  
Massive Compact Halo Objects ◽  
Photometric Measurements ◽  
Analysis System

The Macho Collaboration uses a dedicated 1.27-m telescope (The Great Melbourne Telescope) at Mount Stromlo to make photometric measurements of tens of millions of stars per night searching for the gravitational microlensing signature of MACHOs in the halo and disk of the Milky Way. A prime focus corrector and dichroic beamsplitter provide red (6300–7800 å) and blue (4500–6300 å) foci with one degree fields. A two by two mosaic of 2048 × 2048 pixel CCDs in each focal plane provides simultaneous images of 0.5 square degrees. By August of 1994, more than 20,000, 32 Megapixel images will have been collected of fields in the Large Magellanic Cloud (LMC), Small Magellanic Cloud and the bulge of the Milky Way. We have implemented an online analysis system which produces photometric reductions of a night's data (five Gbyte of images) within 24 hours. This system allows us to identify and follow interesting events in real-time. In this search, we have identified more than 60,000 variable stars, and a preliminary analysis of their types and distribution will be presented. Microlensing events toward the LMC and the bulge have been discovered and detection efficiencies are being calculated to constrain the MACHO content of the Milky Way's halo.

Long term near infrared observation of very bright stars at Kagoshima University

2017 ◽  
Vol 12 (S330) ◽  
pp. 333-334
Author(s):  
Takairo Naagaya
Keyword(s):  
Near Infrared ◽  
Infrared Camera ◽  
Variable Stars ◽  
New Method ◽  
Infrared Observation ◽  
Long Period ◽  
The Status ◽  
Period Variable ◽  
K Band

AbstractWe are monitoring nearby long period variable stars (LPVs) in the near infrared K band to establish their precise Period-Luminosity relation. However, they are very bright in the near-infrared and it is difficult to observe them because they are easily saturated on the modern near-infrared camera. We developed a special ND filter, named Local Attenuation Filter (LAF), to observe very bright stars. Using LAF, we can observe not only the very bright targets without saturation but also reference stars in the same image. We can perform the accurate relative photometry for the bright stars. We present this new method to observe bright stars as well as the status of our monitoring of nearby LPVs.

scholarly journals Tomography of the Atmosphere of the Mira Variable Z Oph

2002 ◽  
Vol 185 ◽  
pp. 428-431
Author(s):  
A. Jorissen ◽  
M. Dedecker ◽  
B. Plez ◽  
R. Alvarez ◽  
D. Gillet ◽  
...  
Keyword(s):  
Shock Wave ◽  
Velocity Field ◽  
Optical Spectrum ◽  
Variable Stars ◽  
Pulsating Stars ◽  
Long Period ◽  
Synthetic Spectra ◽  
Mira Variable ◽  
Period Variable ◽  
Tomographic Technique

AbstractThe new tomographic technique devised by Alvarez et al. (2000) to explore the velocity field across the atmosphere of long-period variable stars (LPVs) is applied to the Mira variable Z Oph. The method cross-correlates the optical spectrum with numerical masks constructed from synthetic spectra and probing layers of increasing depths. This technique reveals that the line doubling often observed in LPVs around maximum light is the signature of the shock wave propagating in the atmosphere of these pulsating stars.

scholarly journals A Dual CCD Mosaic Camera System Searching for Massive Compact Halo Objects (Machos)

1995 ◽  
Vol 167 ◽  
pp. 285-286
Author(s):  
Kem H. Cook
Keyword(s):  
Focal Plane ◽  
Preliminary Analysis ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Camera System ◽  
Massive Compact Halo Objects ◽  
Photometric Measurements ◽  
Analysis System

The Macho Collaboration uses a dedicated 1.27-m telescope (The Great Melbourne Telescope) at Mount Stromlo to make photometric measurements of tens of millions of stars per night searching for the gravitational microlensing signature of MACHOs in the halo and disk of the Milky Way. A prime focus corrector and dichroic beamsplitter provide red (6300–7800 å) and blue (4500–6300 å) foci with one degree fields. A two by two mosaic of 2048 × 2048 pixel CCDs in each focal plane provides simultaneous images of 0.5 square degrees. By August of 1994, more than 20,000, 32 megapixel images will have been collected of fields in the Large Magellanic Cloud (LMC), Small Magellanic Cloud and the bulge of the Milky Way. We have implemented an online analysis system which produces photometric reductions of a night's data (five Gbyte of images) within 24 hours. This system allows us to identify and follow interesting events in real-time. In this search, we have identified more than 60,000 variable stars, and a preliminary analysis of their types and distribution will be presented. Microlensing events toward the LMC and the bulge have been discovered and detection efficiencies are being calculated to constrain the MACHO content of the Milky Way's halo.

Yttrium oxide in M- and S-type variable stars

1966 ◽  
Vol 24 ◽  
pp. 26-29
Author(s):  
P. C. Keenan
Keyword(s):  
Yttrium Oxide ◽  
Spectroscopic Data ◽  
Variable Stars ◽  
Mira Variable ◽  
Type Variable

The spectroscopic data that are being collected for a catalogue of spectral types of M- and S-type Mira variable stars include estimates of intensities of several molecular bands. Since the stronger bands are scattered through various parts of the spectrum it is a slow task to collect observations that allow the different molecules to be compared at a given phase or cycle. Fortunately, the material from the Perkins reflector has been richly extended through the generous cooperation of the Mount Wilson and Palomar Observatories—particularly by the collaboration of Dr Deutsch—so that we can now begin to sketch the behavior of the chief bands.

scholarly journals Leavitt Variables: The Brightest Cepheids Variables and their Implications for the Distance Scale

1985 ◽  
Vol 82 ◽  
pp. 215-218
Author(s):  
Gerald R. Grieve ◽  
Barry F. Madore ◽  
Douglas L. Welch
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Log P ◽  
Linear Extrapolation ◽  
High Luminosity ◽  
Long Period ◽  
Long Period Variables ◽  
Cepheid Variables ◽  
External Galaxies ◽  
Low Amplitude

AbstractTwo low-amplitude variable supergiants in the Large Magellanic Cloud, S65-08 and S65-48 are each found to have periods of approximately 250 days. The cfptical data suggest that these stars are high-luminosity cepheid variables falling more than one magnitude brighter than any other known Cepheids in the LMC. Confirmation of the cepheid nature of these stars comes from their H-band magnitudes which place them accurately on a simple linear extrapolation of the narrower infrared Period-Luminosity relation. So it appears that the cepheid Period-Luminosity relation extends up to Mv ~ -8.5. To honour the astronomer who discovered the first of these highest-liminosity Cepheids, we have sub-classified the variables with log P > 1.8 as being “Leavitt variables”. As soon as these long-period variables are discovered in other external galaxies, reliable distances should be possible out to (m-M) ~30.

Sign in / Sign up

Export Citation Format

Share Document