J/ApJ/818/155 The ELM survey. VII. 15 new ELM white dwarf cand. (Brown+, 2016)
The ELM survey.
VII. Orbital properties of low-mass white dwarf binaries.
Brown W.R., Gianninas A., Kilic M., Kenyon S.J., Allende Prieto C.
<Astrophys. J., 818, 155 (2016)>
=2016ApJ...818..155B 2016ApJ...818..155B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, white dwarf ; Radial velocities ; Photometry, SDSS ;
Binaries, spectroscopic ; Stars, distances ; Stars, masses
Keywords: binaries: close; Galaxy: stellar content; white dwarfs
Abstract:
We present the discovery of 15 extremely low-mass (5<logg<7) white
dwarf (WD) candidates, 9 of which are in ultra-compact
double-degenerate binaries. Our targeted extremely low-mass Survey
sample now includes 76 binaries. The sample has a lognormal
distribution of orbital periods with a median period of 5.4hr. The
velocity amplitudes imply that the binary companions have a normal
distribution of mass with 0.76 M☉ mean and 0.25M☉
dispersion. Thus extremely low-mass WDs are found in binaries with a
typical mass ratio of 1:4. Statistically speaking, 95% of the WD
binaries have a total mass below the Chandrasekhar mass, and thus are
not type Ia supernova progenitors. Yet half of the observed binaries
will merge in less than 6Gyr due to gravitational wave radiation;
probable outcomes include single massive WDs and stable mass transfer
AM CVn binaries.
Description:
We present observations of 15 new extremely low-mass white dwarf (ELM
WD) candidates. Ten objects are selected by color for our targeted
spectroscopic ELM Survey program as described in Brown et al.
(2012ApJ...744..142B 2012ApJ...744..142B). Five objects come from follow-up spectroscopy
of the completed Hypervelocity Star survey.
We acquire spectra for the 15 ELM WD candidates using the Blue Channel
spectrograph on the 6.5m MMT telescope. We configured the Blue Channel
spectrograph to obtain 3650-4500Å spectral coverage with 1.0Å
spectral resolution. We acquire additional spectra for 5 objects using
the KOSMOS spectrograph on the Kitt Peak National Observatory 4m
Mayall telescope on program numbers 2014B-0119 and 2015A-0082. We
configured the KOSMOS spectrograph to obtain 3500-6200Å spectral
coverage with 2.0Å spectral resolution. We also acquire spectra for
objects with g<17mag using the FAST spectrograph on the Fred Lawrence
Whipple Observatory 1.5m Tillinghast telescope. We configured the FAST
spectrograph to obtain 3500-5500Å spectral coverage with 1.7Å
spectral resolution.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 102 62 Clean sample of extremely low-mass (ELM)
white dwarf binaries
table4.dat 37 327 Radial velocity measurements
table5.dat 154 88 Entire ELM survey
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See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
J/ApJ/812/167 : The ELM survey. VI. 11 new ELM WD binaries (Gianninas+, 2015)
J/AJ/150/97 : RVs in M67. I. 1278 candidate members (Geller+, 2015)
J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)
J/A+A/576/A44 : Hot subdwarf binaries from MUCHFUSS (Kupfer+, 2015)
J/MNRAS/446/4078 : New white dwarf stars in SDSS DR10 (Kepler+, 2015)
J/A+A/557/A19 : Mass & age of extreme low-mass white dwarfs (Althaus+, 2013)
J/ApJ/769/66 : The ELM survey. V. White dwarf binaries (Brown+, 2013)
J/ApJS/204/5 : SDSS DR7 white dwarf catalog (Kleinman+, 2013)
J/ApJ/751/55 : MMT hypervelocity star survey. II. (Brown+, 2012)
J/ApJ/743/138 : Spectroscopic survey of bright WDs (Gianninas+, 2011)
J/A+A/536/A43 : SDSS WD main-sequence bin. XII. (Nebot Gomez-Moran+, 2011)
J/ApJ/723/1072 : The ELM survey. I. Low-mass white dwarfs (Brown+, 2010)
J/A+A/513/L7 : Post common envelope bin. from SDSS. VIII (Schreiber+, 2010)
J/MNRAS/402/620 : SDSS WD main-sequence binaries (Rebassa-Mansergas+, 2010)
J/AJ/135/564 : Photometry and spectroscopy of BHB candidates (Brown+, 2008)
J/ApJS/167/40 : SDSS4 confirmed white dwarfs catalog (Eisenstein+, 2006)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name White dwarf identifier (JHHMM+DDMM)
12- 18 F7.5 d Per [0.008/1.1] Orbital period
20- 26 F7.5 d e_Per [0/0.06] Per uncertainty
28- 32 F5.1 km/s K [78.9/617] Semi-amplitude
34- 36 F3.1 km/s e_K [0.5/9] K uncertainty
38- 42 F5.3 Msun M1 [0.1/0.4] ELM white dwarf mass
44- 48 F5.3 Msun e_M1 [0.01/0.03] M1 uncertainty
50- 53 F4.2 --- M1/M2 [0.1/1.2] M1 to secondary mass ratio
55- 58 F4.2 --- e_M1/M2 [0/0.8] Negative uncertainty on M1/M2
60- 63 F4.2 --- E_M1/M2 [0/0.3] Positive uncertainty on M1/M2
65- 68 F4.2 Msun Mtot [0.3/1.5] Total mass
70- 73 F4.2 Msun e_Mtot [0.01/0.3] Negative uncertainty on Mtot
75- 78 F4.2 Msun E_Mtot [0.01/0.4] Positive uncertainty on Mtot
80- 86 F7.3 Gyr tau [0.001/367] Merger time
88- 94 F7.4 Gyr e_tau [0.0001/66] Negative uncertainty on tau
96-102 F7.4 Gyr E_tau [0.0001/91] Positive uncertainty on tau
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Object identifier (JHHMM+DDMM)
12- 25 F14.6 d HJD Heliocentric Julian Date
27- 32 F6.1 km/s HRV [-475/396] Heliocentric radial velocity (1)
34- 37 F4.1 km/s e_HRV [3/48] Uncertainty in HRV
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Note (1): Uncorrected for the WD gravitational redshift.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1 A1 --- New [n] n: new candidate (1)
3- 12 A10 --- Name Object identifier (JHHMM+DDMM)
14- 15 I2 h RAh Hour of Right Ascension (J2000)
17- 18 I2 min RAm Minute of Right Ascension (J2000)
20- 25 F6.3 s RAs Second of Right Ascension (J2000)
27 A1 --- DE- Sign of the Declination (J2000)
28- 29 I2 deg DEd Degree of Declination (J2000)
31- 32 I2 arcmin DEm Arcminute of Declination (J2000)
34- 38 F5.2 arcsec DEs Arcsecond of Declination (J2000)
40- 44 I5 K Teff [7940/34270] Effective temperature
46- 48 I3 K e_Teff [120/500] Uncertainty in Teff
50- 53 F4.2 [cm/s2] log(g) [4.7/7.8] Log surface gravity
55- 58 F4.2 [cm/s2] e_log(g) [0.04/0.2] Uncertainty in log(g)
60- 64 F5.3 Msun Mass [0.1/0.5] Estimated ELM white dwarf mass
66- 70 F5.2 mag gMag [4.5/11.2] Absolute g band magnitude
72- 75 F4.2 mag e_gMag [0.07/0.5] Uncertainty in gMag
77- 82 F6.3 mag g0mag [13/20.6] Dereddened apparent g-band magnitude
from SDSS
84- 88 F5.3 mag e_g0mag [0/0.04] Uncertainty in g0mag
90- 94 F5.3 kpc Dist [0.1/9.2] Heliocentric distance
96-100 F5.3 kpc e_Dist [0.005/1.7] Uncertainty in Dist
102-108 F7.5 d Per [0.008/2.2]? Orbital period
110-116 F7.5 d e_Per [0/0.2]? Uncertainty in Per
118 A1 --- l_K Limit flag on K
120-124 F5.1 km/s K [14/617] Semi-amplitude
126-128 F3.1 km/s e_K [0.5/9]? Uncertainty in K
130-135 F6.1 km/s gamma [-202/126] Systemic velocity
137-139 F3.1 km/s e_gamma [0.8/9] Uncertainty in gamma
141-144 F4.2 Msun M2 [0.07/1.3]? Minimum secondary mass
146-154 F9.3 Gyr tau [0.001/12353]? Maximum gravitational
wave merger time
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Note (1): Flag added by CDS for the 15 new objects observed in this paper
(see tables 1 and 2).
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History:
From electronic version of the journal
References:
Brown et al. Paper I. 2010ApJ...723.1072B 2010ApJ...723.1072B Cat. J/ApJ/723/1072
Kilic et al. Paper II. 2011ApJ...727....3K 2011ApJ...727....3K
Brown et al. Paper III. 2012ApJ...744..142B 2012ApJ...744..142B
Kilic et al. Paper IV. 2012ApJ...751..141K 2012ApJ...751..141K
Brown et al. Paper V. 2013ApJ...769...66B 2013ApJ...769...66B Cat. J/ApJ/769/66
Gianninas et al. Paper VI. 2015ApJ...812..167G 2015ApJ...812..167G Cat. J/ApJ/812/167
Brown et al. Paper VIII. 2020ApJ...889...49B 2020ApJ...889...49B Cat. J/ApJ/889/49
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-May-2016