Questions about Jao et al. 2005

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Questions about Jao et al. 2005
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Red Dwarfs 1025 pc
Red Dwarfs 10 (25) Parsecs
CTIOPI targets gt 250 47 new red dwarfs 2 new
white dwarfs (as of 26 JAN 2009)
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RECONS Census Update
trigonometric parallax gt 100 mas and error lt 10
mas as of 2009.0
2000 WD 18 A 4 F
6 G 21 K 44 M 199 L
0 T 1 planets 2 Total
295
pub 2009 0 18 0 4 0 6
0 21 0 44 40 239 4 4 7
8 8 10 354
unpub now 2 20 0 4
0 6 0 21 0 44 17
256 0 4 0 8 1
11 374
6 1 2 6 13 73
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Parallaxes Supergiants
I I/II types 219 in HIP 167 gt 10 p err
Jao 2008
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Supergiants with SIM
Jao 2008
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Hipparcos vs. SIM
Jao 2008
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Naked Eye Stars
Betelgeuse 152 20 pc
Bellatrix 77 3 pc
Current Hipparcos (2008 reduction) avg error in
? 12 avg error in lum 25 avg error in mass
37 Future Gaia cannot do (too
bright) SIM errors will be ? ltlt 1 lum lt
1 mass lt 1 errors if binaries found at these
distances
Mintaka 212 26 pc
Alnilam 606 174 pc
Alnitak 225 33 pc
Rigel 265 24 pc
Saiph 198 9 pc
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Bright Stars in General

• How far away is
• THAT
• star?

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Measuring Stars with Astrometry
Astrometry is measuring the position of light
sources. proper motion parallax
orbital motion
Keplers Third Law M1 M2 a3 / P2 M1
mass of the primary in (M?) M2 mass of the
secondary (M?) a semi-major axis of the
relative orbit (AU) P orbital period (yr)
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OrbitsMass-Luminosity Relation
O stars M stars
what is the biggest star?
what is the smallest star?
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HSTs Fine Guidance Sensors
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FGS-TRANS
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GJ 469 ABwith HST

• astrometric orbit 1992
• first resolved HST-FGS 1995
• first reliable orbit 1999

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GJ 469 AB orbit progression
P 11.6 yr a 314 mas
orbit covered error in P error in a
51 4.96 4.29
60 3.58 3.00
68 2.07 1.78
77 1.23 1.07
84 0.67 0.57
89 0.44 0.39
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Orbits Red Dwarf MLR
?
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GJ 1245 ACwith HST

• astrometric orbit in 1984
• first resolved IR speckle 1986
• following with HST-FGS
• P 17.16 yr
• a 828 mas

A 0.113 0.002 Mo C 0.074 0.002 Mo
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RECONS HR Diagram
End of the Main Sequence? GJ 1245 C 0.074
0.02 Mo
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Past the End GJ 1001 BC
HST NICMOS ACS VLT NACO
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GJ 1001 BCwith HST

• first resolved NICMOS 2002
• following with VLT-AO
• P 4.10 yr
• a 91 mas

B 0.055 0.014 Mo C 0.045 0.012 Mo
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ASPENS
Astrometric Search for Planets Encircling Nearby
Stars

• with Dave Koerner
• Northern Arizona
  University
• upgrade from photographic plate work to CCDs
• 10 years of data on 100 red and white dwarfs
• detection limit few MJup

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GJ 831 AB
known binary red dwarfs Pphot 1.96 yr aphot
27 mas Ptrue 1.93 yr atrue 145 mas A
0.25 Mo B 0.16 Mo
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LHS 3738 AB
new binary red dwarfs Pphot 6.83 yr aphot 28
mas A 0.3 Mo B 0.2 Mo
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WT 460 AB
new binary redbrown dwarf Pphot 20 yr aphot
70 mas A 0.15? Mo M5.0 V B 0.07? Mo
L1.0 V
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G 099-049astrometry SEP 2007
red dwarf planet? Pphot 6.25 yr aphot 8
mas A 0.19 Mo B 4 MJup
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G 099-049velocities NOV 2007
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last year does not compute
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Cracked V Filter
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